I wasn’t a huge Air Supply fan as a teen, but I did love this song. It got me through quite a few break-ups during the 80s. 😉

Chris wrote this article on Mar 4, 2014. It was listed as incomplete.

So just how much can be said about a tap wrench?  It turns out, a bunch more than I thought just a week ago.

A couple of weeks ago I made my Z-setter.  I was pretty happy with it even if I did make a couple of mistakes.  The Z-setter has 5 tapped holes, four of them blind.  I was originally going to go with #8 screws but those were too big, so instead I choose to use #6 screws.  Because of the blind holes, I stopped at the local industrial supply store and tried to buy a set of #6-32 taps. Since they only sold them individually, I picked up the taper and bottom taps and planned on using the plug tap from my “tap and die kit”.

Well these are slightly smaller taps than I normally use.  My normal “small” size is 1/4-20 and those never give me a problem.  Well in this case the T-handle tap wrench in my kit wasn’t able to close on the tap.  And this is suppose to be the “small” wrench.  In the end I used the flat wrench which just barely worked.

To tap the holes I first drilled them to depth then switched to holding the tap in the drill chuck.  I then took the mill out of gear and turned the spindle by hand to tap the first part of the holes.  I wasn’t sure of the “feel” so I was worried about bottoming the tap and stripping the threads or breaking the tap so I didn’t go very deep.

Once all the holes on the top had been drilled and the threads started, I removed the part from the vise and attempted to tap them by hand.  It was at that point where the limit of this particular tap wrench showed itself.

This is the T-handled tap wrench that came with the kit.  Starting at the top we can see different features of its construction.

1. The handle is chromed with grooves at both ends to act as a detent for the ball latch in the body.
2. The body is also chromed.  At the top is the hole for the handle.
3. A hole has been drilled through the top to the handle hole and then counter drilled.  The counter drilled part has been tapped.
4. Handle retaining system.  A ball has been placed in the hole at the top, a spring is placed on top of that and the pair is captured with a set screw.
5. The chuck is blackened and may be hardened, I’ve not checked.  It has a fairly coarse knurl with two decorative grooves cut in it.  The inside is tapered but the quality is nothing special.
6. The jaws are an integral part of the body.  A hole is drilled from the mouth of the body and then the body is slit so there are four jaws.  The jaws seem to be designed to hold a round and not square shaft.

When using this tap wrench, as you loosen or tighten the chuck the smoothness changes depending on how and where the chuck is on the body.  It does not matter if there is a tap in the wrench or not.  It is difficult to tell if the tension felt is because the jaws are squeezing the tap or if it is just the spring in the jaws.

In the case of the #6 tap, it felt like there was a good purchase on the tap but as soon as there was any tension the tap slipped.  In other words this tap wrench is a low cost imported pseudo tool.

Now we come to the point of this review.  The orgasm inducing (or at least helping to get there) Starrett 93A T-handled Tap Wrench.

The first thing I noticed was that the handle didn’t have the retaining grooves I’m used to.  Instead it was a simple steel rod, slightly tapered at both ends with the corners nicely rounded/broken.  It had a nice heft to it.  At first the fact that it wasn’t chromed sort of made me wonder.

Then I slid the handle into the body of the wrench.  The handle stayed where I put it.  It doesn’t slide around like “normal” tap wrenches.  I slid the handle around and it had just the right amount of friction.  I could center the handle and it stayed put.  I could move it to one side and it stayed put.  When I removed it the friction was constant until I reached the taper.

Examination of the handle hole revealed why.  While the body had the same handle hole and top hole as the import, the top hole was there for centering, not for the retention hole.  Instead of the “normal” ball retention Starrett cut a small grove for a retainer spring clip just inside the handle hole.  When the handle is inserted the retainer expands into the groove while holding onto the handle.

The reason the handle is not chromed is that this retainer system would likely scrape the chrome off if there was ever a chip or scratch made to the handle.

The centering hole means you can use a tap follower to guide the tap as needed when starting the tap.  Instead of putting the tap in the drill chuck and then turning the chuck by hand I could have placed a center point in the chuck and then used that to hold the tap vertical as I started the tap.  This would have given me exactly the feel I needed to make good threads.  It also means that if I had multiple taps (taper, plug and bottom) I could have the ones I needed in different wrenches and instead of having to change out the tap in the chuck I could just remove the one wrench and use the second wrench with the other tap.  Much faster.

Next we move to the chuck itself.  Unlike the import this has a medium knurl and it is beautifully done.  The chuck is also blackened and it looks to be hardened.  I’ve not tested but given that it is a Starrett I trust it to be what it looks like.

Side note: I bought a tool kit for the office.  It came with a set of hex wrenches.  The wrenches are blackened which normally tells me that the tool is hardened.  The first time I went to use one to tighten the nuts holding the desks together the wrench twisted rather than the screw moving.  While the blackened color said “hardened” the reality was, “Not much better than pot metal.”

When you look into the mouth of the wrench you can see that there are two jaws.  The jaws have 90deg V’s cut in them and are blackened and hardened.  When you turn the chuck on the body the motion is very smooth and the tension stays constant from fully closed to fully opened.  The threading is what you would expect from a company that made their name by providing precision threaded tools (micrometers).

When the chuck is removed the first thing you notice is that the body has a slot milled in it.  This slot is wide enough to  hold the jaws and the jaws ride within this slot.  The body does not flex as the chuck is screwed off or on.

The jaws are spring loaded so that they move outward.  In another tap wrench I own there is a standard coil spring between the two jaws.  When the chuck is removed the jaws want to fly apart with the jaws going in two different directions and the spring a third.  It is important to make sure you don’t let the jaws spring apart like that as you take the chuck off the body to free the jaws.

Well, on the Starrett tap wrenches I didn’t really have to worry about the spring or jaws flying apart.  Instead of a coil spring there is a bent wire spring.  At the end of the milled slot the body is drilled.  The bend of the spring slides into that hole.  The other two ends have a hook at the end and these are press fitted to the jaws.  When the chuck is removed the two jaws and the spring remain as a single unit attached to the body.

The jaws and spring unit can then be removed.  The entire tool can be cleaned and lubricated and put back together.

There is a reason why Starrett 93A sells for $29.14 on Amazon and the Irwin tap wrench for the same size range sells for $8.50.

I’ve added the next two sizes of Starrett T-handled tap wrenches to my wish list, the 93B and the 93C

Jaw sizes for the three Starrett T handled tap wrenches are:
93A – 1/16-5/32
93B – 5/32-1/4
93C – 1/4-1/2

Since January 2026, there have been 11 deaths by ICE shooting. I’m sure you can name a couple of them, but can you name all of them? Probably not. I follow this stuff, and I had to go look them up, even the ones I knew fairly well (Pretti and Good). On a side note, I look at those numbers and consider it pretty good. That isn’t even 2 hours on a Friday night in Chicago. But I digress.

The reason we’ve all forgotten about those folks is a) they’re in the past and the news has (largely) moved on to other, more fiscally positive things, and b) they’re dead. There’s no one to bitch about how put out they are. And therein lies the crux.

I will state, first and foremost, that I do not like war, I do not support war, and I do not want war. However, I am also a pragmatist. War happens, and we must be prepared to deal with it if it arrives. People who are completely peaceful and who refuse to defend themselves have a name: victims. I do not wish our country to be victims. Therefore, whatever my personal *feelings* are, war is something that will have to happen occasionally.

In the past, small countries would get themselves attacked by America, because then America came in, set up a government, fed them money, and got them on their feet again. That’s been our rules of operation for a very long time. It’s served us almost as well as it has served those countries, in my opinion. We’ve helped much of the globe achieve capitalism and democracy of some sort, and the level of violence around the world is extremely low right now. That’s largely to do with us.

Iran is not one of those small countries, though. It is poking the bear, repeatedly. They* believe, firmly believe, that Allah will bring them glory if they fight the United States. They believe, absolutely, that if they poke the bear and have an actual war instead of the current pissing contest that’s going on, they will win. Of course, if they don’t win, they all go to Allah and get their virgins or whatever, so they can’t lose either way.

It is time for us to send them to Allah, boys and girls.

I don’t want us to drop nukes. That would open too many doors to too many devils. But we easily have in our hands the means of busting their bunkers and sending the lot of them to their god. And I believe, just as firmly as they believe in Allah, that it’s time to do some busting.

The longer we carry this current “war” on, the less the American people are going to support it. I posit that, had Trump gotten permission early on and just bombed them into the Stone Age, by today everyone would be reacting to it the same way we’re reacting to stuff about Good and Pretti. We’d have mostly forgotten it, because it wouldn’t be getting anymore news cycles. Dead civilizations don’t complain. They are silent. And they’re not fun to write news about, past the initial few weeks.

Trump has flame retardant boxers. He has the means and the reason to do this. It needs to be done, not just for America, but for France and Britain and Germany and all the other countries of the world who are being overrun by these people. We’ve entered the time of the paradox of tolerance, and it’s time to just STOP. Once we bomb them, they can have their newly sanitized country back. We can put a few decent rulers in to start, and warn them that if they start up that shit again, we’ll put a wall around them and leave them to starve, but they’re never doing this diaspora crap EVER again.

Trump no longer has reason to be nice to anyone. Before he loses the last of his “unlimited” (hah) power having all 3 branches of the government, can we PLEASE get this done?

*They, defined as those folks who consider themselves old-style Muslims, intent on killing everyone who isn’t already a Muslim and isn’t willing to convert. I don’t care about those who have become Americans (and I don’t mean “become” as in getting their paperwork… I mean as in assimilated to our culture). Americans are who we’re protecting. I mean those who want the death of Americans and capitalists as a whole. And I realize y’all don’t care about that definition, but I do, so it was important to me to put it in here.

Historically, the Left and the Right have done a dance every four to six years. Things switch around, little gets done, and the government is hobbled by one thing or another. For the past two years, that has not been the case. The Right has had the Presidency, the Senate, and the House, all wrapped up in a pretty bow. We know this, because things have gotten done. We’ve weeded out some (but not all) corruption and fraud. We’ve slowed illegal immigration. We’ve deported many violent criminals. We’ve ended a bunch of stupid things, like regulating plastic straws and funding foreigners studying birds in other countries. We’ve started the process of returning men and women to their biological places (and, as far as I can tell, largely without causing any major harms to folks who really are transgendered and just want to be left alone).  We’ve worked on lowering taxes in some places (but raised them in others). Most importantly, the tariffs have forced American companies to start producing things that we had outsourced to other countries, thereby strengthening our economy.

Despite all this, the Right was *crushed* in this midterm election. I’m curious to find out why this happened. The options, as I see them:

• Republicans didn’t get out and vote, something they’re VERY bad at during midterms
• The current vote shows the public decision in regards to what’s been done with the government (valid, even if I dislike it)
• The split caused by the GOP made for hugely bad optics and left many middle ground voters confused and unsure.

My best guess is the last one, though it could be mixed with the first. I don’t think so, however. It’s also possible for all three of the above to be true at the same time.

The war with Iran has been massively unpopular, even among Republicans and general conservatives. While I agree that Iran should not have nuclear missiles, and I also agree that Islam is causing huge problems that need to be dealt with in our country, we should not have stayed in this war. We should have gone in, struck, and got the fuck out. The six weeks Trump promised us have slid into eight months at this point, with no real end in sight. This was NOT what Republicans voted for; it’s the exact opposite.

Inflation has been hard. There are a lot of items that are still very expensive, and coming into the holidays that’s a hard sell. I know the President doesn’t have any magic way to deal with that, but there are certainly ways Trump could have eased the pain (and without handing out cash… that “offer of $5000 if we sweep the midterms” was crass in my very strong opinion). I have no real issue with the current prices, even though I wish they were lower. But I know how to make “freezer scraping soup” when necessary. Most folks today have no clue. No one knows how to make beans and rice 18 different ways anymore. Soup has gone out of style, unless it’s bougie expensive stuff. If the government had worked on something akin to the Victory Garden idea, offering ideas and help to the people in planting gardens or how to cook cheap meals, I think that would have gone a long way. While Kennedy did some of that, his methods of trying to “reach the people” were pretty off the mark, again in my opinion. He’s been rich long enough that he’s never truly had to scrape, and it reflects in what he cooks. Not enough rice and beans, folks. When my most popular videos on my author TikTok are about cooking cheap meals, the government is not doing enough to educate people.

The tariffs have been a huge loss for many people. I have the ability to look far enough in the future to see how it benefits us, but our government did next to nothing to explain to “the plain folks” how this stuff works. I know, because I was watching for it, and it never arrived. I’m certain part of that is because the people doing it are, frankly, quite old… they know how tariffs work because they’ve seen them used in the past… and “everyone knows” about how they work, right? Wrong. Starting off with a lot of education on how We the People get shafted by every other country on the planet would have been great. Adding tariffs in AFTER that would have caused (hopefully, at least) a wave of patriotism. You have to build the brand first, THEN launch. You can’t launch then scramble to get caught up.

Trump didn’t push the SAVE Act through. That should have been the number 2 priority after getting out of that damn war.

And while I do think there are bunches of very valid reasons for building a ballroom, Trump and team did NOT read the room before doing it. Building something perceived as vainglorious (regardless of who’s paying for it) is never going to go down well when people are suffering in the grocery store and at the gas pumps. The idea was good, but the application was horrendous.

Over on TikTok, someone asked if “real Republicans” would answer a question: When you voted for Trump, did you vote for him to dismantle the Department of Education? I explained that I’m small “c” conservative, not Republican but certainly Republican aligned (especially right now), and definitely not Left… and yes, that is indeed what Republicans voted for, en masse, and happily. And then I explained that, Left or Right aside, the government has (and always will have) the Reverse Midas Touch. Everything the government touches turns to shit. So I want my government to touch as little as possible. When asked what that meant, I said we should have a government that fits inside the Constitution… and we currently do not, and that’s wrong. Even other Right Wingers have been debating me, pointing out things they think are good that are done by Big Gov. My answer is always going to be the same: if the Right can do something with the government, then the Left can also do something. Since the Right and Left are diametrically opposed (moreso now than at ANY other time in history), that means we should not be allowing the government to do much of anything.

Trump had the right idea with DOGE, but he let other people find ways to derail it before it could remove the worst of the bloat from DC. The big ticket that both sides have seemed to want is the idea of term limits for Senate and House… and that hasn’t even been mentioned among the up and coming elected folks.

I’m disappointed today. I wanted to see at least equilibrium. Seeing the blue wave is disheartening. Any further forward movement by Trump will have to be done by EO, and those are easily turned over with a swipe of the magic pen by the next person in office.

With House and Senate in Democrat control, I foresee Trump’s impeachment and removal from office. That leaves Vance, who is a great candidate. But I don’t know if he’s ready. It’s one thing to be VP… it’s quite another to be the President. Don’t get me wrong… I do want him as President. I just don’t know if right now is the correct moment for it to happen. I hope he’s ready. I think he has the ability to find a middle ground that will be less hated by the Left, and only a little hated by the GOP. He’s fairly good at dancing around that line. And he has good ideas, a strong family life, and his family is “diverse” as the Left likes to call it. While it has absolutely nothing to do with how well he does his job, and we know that, the Left DOES care and so we may as well compound on that.

Hegseth, also, is probably on the chopping block. I hate that. I think he’s done more for the US Military in his short time in office than anyone else since the World Wars. I’ve seen so many men and women in uniform truly excited and happy to be there, after years of feeling trodden on.

It’s an emotionally rough day today. Don’t let yourself get dragged into bad conversations. Give yourself space. And don’t get angry… get educated. I mean it! The Right lost… big time. Don’t spend one fucking second whining about it. Go find out why. Figure it out, and then fix it. That is LITERALLY the only way out of this mess.

Sometimes it’s just nice to have something playing in the background while you work. This felt good for all sorts of stuff! Enjoy some old timey music. 😉

Chris wrote this article on Feb 15, 2014.

Along with all of the fun metal working toys I have I also have a CNC Router that I built from scratch.  Last fall (15 months or so ago) I managed to make a stupid mistake and broke it.  I destroyed part of the Z axis, burned out the router and managed to do something to the electronics.  In the end it turned out that the issue was a broken wire in one of the motor connections.


I fixed the physically broken parts and then realized that the electronics weren’t working.  Two weeks ago the electronics on the CNC made it back to the top of my list and I purchases a G540 4 axis controller and break out box.  I bought it from CNCRouterParts.com  A damn good company.

As I was going through their website I saw a Z axis position setter for only $90.

So what does a Z axis setter do?  Well when you are using CNC you need to know where your material is.  Normally X and Y axis aren’t critical because you just want to make sure you are cutting inside the material.  If it is critical then you can do standard edge finding but it doesn’t happen very often. 

The more critical position is the Z axis.  If you miss the surface by a few 1/1000s you could end up cutting to deeply or you could cut to high and miss features.  Worse, it is often the case that you will change tools in the middle of working a complete CNC program.  If the tool you put in is not have exactly the same stick out as the last tool or you don’t know exactly how much it sticks out your 2nd (or third passes) could cause problems.

If you are doing CNC work you often do a roughing pass.  As long as you don’t turn off the machine your X and Y axis will stay exactly the same.  When you change tools for the finishing pass unless you get the tip of the tool exactly right then the roughing and finishing passes might not match up.  Leaving a poor result.

There are lots of ways to set the Z axis.  You can use the paper squeeze where you put a paper under the bit, lower it till it is “stuck” then slowly raise it till it is barely free.  You know know your bit is exactly the thickness of the paper above the surface.  You can use a dowel pin that is exactly 0.500 thick.  You lower the tool until you can no longer roll the pin under the tool, then you raise the bit until you can just barely roll the pin under the tool.  Then you know the tool is exactly 0.500 inches above the surface.

There are other methods but they all are slow and have the potential of error.

In the best of all worlds you would want to change the tool then just press “figure it out” and have it “work.”

That’s where a Z setter comes into play.  A Z setter acts like a Normally Open (NO) switch.  There is a sensor plate which is on one side of the circuit.  The tool is attached to the other side of the circuit.  When the tool touches the sensor plate the circuit closes and the computer senses that the tool is exactly sensor plate away from the surface of the work.

You could just use a flat plate but that plate has no give to it, so when the tool touches down it puts lots of stress on the CNC system unless the tool is moving very slowly.  I originally tried a piece of printed circuit board but it was too light and flexed upwards causing still other problems.

This Z setter is designed to protect the tool as well as be heavy enough so that it doesn’t flex or move when placed under the tool.

The design is a 2in diameter cup with a spring loaded plunger.  The entire cup is one side of the circuit.  When it is time to set the Z axis the setter is placed under the tool and then a CNC program is run.  The program does a rapid lower.  It doesn’t matter if the tool bit hits “hard” as the AL is softer then the tool bit and the plunger will give.  Once the program detects that it has touched the plunger is backs out rapidly until the tool is no longer in contact with the plunger.  At that point the program lowers the tool at a much lower rate of speed but it only has to go a short distance so this doesn’t take long.  When the tool touches down we know exactly where the tool is relative to some surface.  (top of the work or the bottom board or something else.

I plan to make a second z-setter.  This one will be placed in a fixed position on the router table.  This will give us an absolute Z location.

To start using the program we would use the movable Z setter to determine a point above work surface.  (We don’t have to use the movable Z setter for the bottom of the work because that can be determined from the absolute location from the fixed Z setter)

With two Z locations, one absolute and one relative we can calculate an offset and remember that offset.  When we change tools we can recalculate the offset from the absolute Z and not have to measure to the work surface again.

Enough about what a Z setter is, let’s get into making it.

I started with a 2.250 round of AL that was 12 inches long

I set this up in the 3 jaw chuck and then added a steady rest way out at the end.  My son Michael then faced it off and turned a section about 0.375 down to 1.500 +0.000 -0.005.  This was parted off to create the plunger/plug.  When parted off the part ended up about 0.250 thick with a very smooth top space.  I was pretty happy as we hit 1.499 for the diameter.

Next the work piece was faced and a section a little longer than 1.000 was turned down to 2.000 +/- 0.005.  I hit this at 2.000 which was very nice.  Now that I had the diameter of the cup and retaining ring established it was time to start boring.  I started with a center drill  then I drilled with my largest drill 0.500.  I drilled 0.750+ a little more deep.  I do have a 5/8 and 3/4 in drills but they are MT2 and the tail stock is an MT3.  I’ve not yet gotten the adapter sleeve.

After drilling I then set the micrometer stop and started boring.  The goal was 1.375 +/- 0.20 diameter.    This is the interior diameter of the retaining ring.  Once the bore reached diameter a slice 0.063 was parted off.  Since one side was faced it was “perfectly” smooth. This face will be against the top of the cup and plunger which will bring the plunger into alignment with the top of the cup.

Next the cup was again faced and the boring was continued.  The goal was 1.500 +0.005 -0.000.  When I hit the 1.500 mark I test fitted the plunger and decided it was a little to tight so I took another 0.001 off the diameter.  The final size of the bore was 1.504 which gave a loose slide fit to the plunger.

At this point it was time to part off the cup.  The cup was parted off at 0.800 to leave some room for facing and finishing to 0.750.  I had to make some soft jaws, actually brass shim stock to cover the jaws of the chuck.  I seated the piece against a pair of parallels then faced of the base.  Once the base was faced off I flipped the piece over, touched off, measured and cut to 0.750 +/- 0.000  I was able to hit this to the limits of my ability to measure (0.0001 on my micrometer)

Now that the major pieces are shaped it is time to drill and tap some holes. I wanted four screws in a standard bolt hole pattern 0.125 from the edge.  After doing a little research I decided on #6-32 as my screw size.  A #6-32 hole is produced by a #36 drill bit.

The fun comes from the fact that I don’t have a fully functional DRO.  I only have Y axis capabilities on my DRO.  This of course complicates just about everything. 

To place my 4 holes in the bolt circle the right way to do it is to locate the center of the circle by sweeping the outside edge.  When this is done you keep track of which way the table was being moved when you found center.

From that point on you can move to the correct X,Y coordinates based on your dial settings as long as you are moving in the same direction as when you found center.

I was able to cheat a little bit.  Because I have one axis working with my DRO I’m able to locate the center value of Y.  At that point I move to just outside the cup in the X axis, move towards the cup until my edge finder twitches.  From there it is only a mater of turning the dials .225 in the same direction to end up where I need to go.  The extra 0.100 is to adjust for the size of my edge finder.

This gets me the “left” and “right” holes.  From there I just need to move in to 1.100 to be at the exact center of the cup.  A quick down stroke with the spindle and I can see that it is lined up exactly with the center of the cup as indicated by the drilled hole.

Using my Y axis DRO I’m quickly able to move to the correct locations for each hole and drill them.

In order to start tapping each hole vertically I’m actually doing three tool changes for each hole.  I start with the edge finder, touch off, move to final location, change to the drill bit, touch the top of the cup, set the stop to 5/8″, drill to depth.  Switch to plug tap, take the mill out of gear, twist the drill chuck by hand to slowly tap the hole part of the way. 

I didn’t go as deep as I could have because I was afraid I would not be able to feel when the tap hit bottom.  I’ll have to test sometime when I’m not worried about destroying 4+ hours of love labor.

Once the four holes were drilled and the tapping started I took the cup out of the vise and started to hand tap the holes the rest of the way.   At which point I started cussing Grizzly.  The tap set I bought from them has taps that start at #4 and go up, but the tap wrench doesn’t actually HOLD a #6 tap!

I ended up using the larger wrench and driving the square at the end of the tap.  This worked fine and I was very careful to feel when I hit bottom.  I had picked up a taper tap and a bottom tap as well so I finished out with the bottom tap.

Next I put the cup back in the vise on its side.  I used the edge finder to locate one side of the cup and then move to the center of the cup.   A quick edge find off the bottom and I moved 0.250 up from the bottom to drill and tap the edge hole.

This all seemed to work exactly as expected.

Now it was time to drill the clearance holes in the retaining ring/disk.  I carefully placed the ring in the vise, found the right place to drill, used the 9/64th drill with parallels holding up the sides.  The drill started cutting in with no problems.  A little tap magic did wonders.

Then as I went a little further the drill seemed to “stick” and the disk suddenly flexed and bent.  I repositioned the parallels for better support and finished drilling my holes.  Boy were they ugly.  The forth hole was the worse.  I barely started to drill when suddenly the ring popped out of the vise. 

I checked and there was a good mark so I went over to the drill press.  There I saw the drill cutting just fine and then again it seemed to stick.  I finished the hole with a little more pressure then cleaned up the ugliest holes I’ve drilled.

When I went back to get the drill bit I finally looked at the bit.  The cutting edges fine, but about 1/4 inch back from the cutting edge the bit suddenly got “larger” as if there was a second very bad cutting edge.  The bit is no in the garbage.

The end result was one hole that was misplaced so that I can’t get a screw into it.  I’ll go back and open all four holes up a little bit more (and clean them up).  This will allow all the holes to align.

Here is the Z-setter being put together:

The spring under the plunger might be a little two strong and a little to small but both can be easily adjusted later.

The retaining ring is then placed on top:

And here is the letherman screw driver acting like the cutting tool pressing down the plunger(sorry for the bad focus):

The South Bend 13″x5′ that I used to turn the parts.  I’m hoping that someday it will be warm enough to enjoy cleaning it a bit more.  These chips are almost all from this project.:

Thats a DoubleBoost light pointing down at the three jaw and my Walmart special off to the back.

Here is the Bridgeport used for drilling the bolt hole circle:

Any rust you see on any of these machines came with the machines.  I’ve been cleaning and fixing as fast and as much as I can.  This vise was frozen when I got it.  I’ve cleaned it and it is now mostly in good shape.  The fixed face and bottom of the vise are in very good condition with the exception of a couple of nicks on the fixed face.

A special thanks to Marc L’Ecuyer for his rapid response to tell me how to do x,y bolt hole circles right and for some great teaching videos.

Doubleboost for his fun videos and methods.

Tom’s Techniques for more great learning videos.

Oxtool, Abom79 and Kieth Fiener for production machinist videos.

And of course, Mr Pete (tubalcain) for the videos that got me started

So if you’ve been on social media at all in the past week, you’ll have seen the warnings going out to many countries. (Newsweek, WION)

Why is it suddenly now that governments are warning their citizens to prepare? Well, the short answer is, it isn’t “just now.” Most of Europe has been telling their people that for just over two years now. It just hasn’t made the news here. And of course OUR news is now saying this is something new, something terrifying. Because, you know, storing enough food, water, and heat for 72 hours is absolutely scary.

I could say all this is because of Iran and other places (mostly in the Middle East, but let’s not forget China and Russia) are gearing up for bigger war. This is no longer a matter of a few people lobbing minor bombs at Israel. Things are mobilizing, and the last six months have been much more active. While I feel like Trump has probably brought much of this to a head, I don’t see it as “his fault” at all. Instead, I expect that he’ll squeeze it like a zit and relieve the pressure. Or at least that’s what I’m hoping for.

I don’t want us to be at war. On the other hand, I don’t want the Middle East having nuclear capabilities, either, because they seem quite willing to use everything they get their hands on.

So officially, we here in the States have also been warned to have 72 hour kits at the ready. Our family is prepared; is yours?

I ask this not because I’m being facetious or rude, but because I have always thought it wise. Right now, too many people are playing stupid games, and I’m waiting for us to start seeing people winning stupid prizes. Having 3 days (or more) of necessities on hand is not just what we’re being asked to do… it’s the smart thing to do.

What kind of things should you have on hand? Well, think about that whole Rule of Threes thing Chris and I harp on about. First aid kit for sure. Shelter (which is not just your house or vehicle, but also how you heat that shelter…. do you have firewood or gas to run an indoor-safe heating unit if electricity goes out? do you have blankets, both to block off the room you’re in so you’re only heating one space, and to huddle under because the weather is getting hella colder right now?). Water, because if the electric goes out, you may not be able to use your taps. Now’s a good time to crack open the taps and fill up a bunch of water containers, and just keep them on hand. Just in case. You might want to get water purification tablets if you’re concerned about a longer power outage and lack of water.

Food is essential, but that also includes how you’re going to cook it. While you can absolutely open any can or tetra pouch and just eat what’s inside, cold, it isn’t yummy. You can make some really yummy meals that are quick and easy from canned goods, stuff that will keep you full and healthy. If you’re in a home and not a vehicle, you can always use a Buddy Burner backpacking stove. These can be used outdoors, but they can also be used in a house if you crack a window (while they do make carbon dioxide, there isn’t much more than you’d find in a candle or three, so a cracked window is probably overkill but smart). These can be used easily just by lighting them up and popping a few stones or bricks around them to hold a pot at the right height. I have an old fry basket (steel metal basket, mostly holes) that I turn over the thing, and it holds a pretty large pot. If you’ve got a gas stove, the top will continue to work even if your power goes out, but be gentle on the gas usage. When you’re out, you may not be able to get more. And of course  you may have a bbq with a gas burner, or one of those big outdoor gas burners. And if all that fails,  you can build a fire and cook over it.

I’m prepared for an emergency lasting up to a few months. I’d prefer not to cook over a fire in the snow, but goodness knows I’ve done it before. We have wood. We have a fire pit if there’s a reason for a raised fire. We’ve got a wood stove inside. We have oil lamps and lots of oil. Loss of power, water, etc. really isn’t a huge blow. It just makes life less convenient, but not overly scary.

Are you ready for something? EMP, or bomb, or sabotage?

Hi folks. Chris and I are working on updating the blog infrastructure, getting rid of the spammers, and getting active again. Please bear with us. Good stuff IS coming, if a bit slowly.

Chris wrote this (UNFINISHED) article on Dec 30, 2013

So I have a small machine shop.  Well sort of, the fact that I have a Southbend 13″ by 5′ tool room lathe and a Bridgeport knee mill sort of implies that it is a bit bigger than “small”.  When comparing to the people I follow on YouTube such as “Mr Pete/Tubalcain”, “Doubleboost”, Keith Finner(sp), Adam, Oxtools and Tom’s Techniques it feels small.


As I started down this path I had already read many books on how to use the lathe and it seems like a simple enough machine.  I’ve read a few more books and watched a boat load of good videos on machining.  What I’ve learned is that the machine is cheap, it is all the stuff you have to get to go with it that gets expensive.

In the shop there are a number of different general operations that take place:

• Metal Removal
• Metal Addition
• Metal Forming
• Metal Casting

Metal Removal

Metal removal is the process of removing unwanted metal.  There was a joke attributed to some famous sculptor “How do you make such beautiful statues?  Well I just remove all the marble that shouldn’t be there.”

Metal removal general starts with a casting or a piece of stock and removes unwanted metal until you get what you want.  The goal is to remove the least amount of metal as possible in the shortest period of time safely.

The Milling Machine

Take one very simple thing.  Holding something on a milling table.  You’ve got this great big table, it has T slots, it has the ability to move a 0.0005 in any direction with the turning of a knob.  And you have no way of holding anything to the table.

Enter the Milling Machine Problem.  A milling machine is simple compared to a lathe.  You attach the work to the table, you set the speed, you insert the tool and then you move the table around until you get the result you want.   Nothing real hard about it.  That is until you realize that attaching work to the table IS the big issue for milling.

So you get your first holding pieces.  This consists of “packing”, “straps”, “bolts and nuts.”  The packing should be just a little taller than the work piece.  The bolt should be closer to the work piece than the packing.  By tightening the nut you squeeze the work against the table.  Now you have the work attached to the table.

Except that the work is likely not aligned with the table.  So before you can actually attach the work to the table you have to make sure that the work is “perfectly” in line with the axis of motion of the table.

Well, this goes on and on and on with figuring out how to attach and align things.  (The quick answer is that you attach something to the table with a small space, such as from an index card, between the item and the table.  Then you mill that thing by moving the table in only one axis.  This gives you something that is perfectly aligned with the table.  From there you attach work to the table and tap it so it is hard against the milled surface, thus aligning the work with the table.)

It turns out that many operations can be done with just a simple vise.  If you attach a vise to a milling table then you can attach the work to the vise (close the jaws TIGHT) and be ready to work.

Well, to do this you need to put the vise on the table then to adjust it so that it is exactly aligned with the table movement.  This requires that the milling vise have a jaw that is flat.  The jaw must be square to the bottom of the jaw mouth.  The jaw mouth must be parallel to the bottom of the vise and the bottom of the vise must be flat so it can rest flat on the milling table.

You can pay anywhere from $300 to well over $800 for a six inch milling vise.  But things don’t stop there.  In order to get the work above the jaws the work has to either be tall enough to begin with or you have to put some sort of packing under the work to lift it up.  This is done with parallels.  Well parallels come in an amazing array of different types.  There are “wavy” parallels that are designed to fit under very narrow items and which can be squeeze a little and still maintain their lift.  There are narrow parallels (0.125″) as well as 0.250 and 0.500″ parallels.

You need an indicator holder that can be held in the spindle so that as you move the table you can see if the vise is aligned with the table movement.  You need hammers to pound the work down to make sure it is sitting flat on the parallel.  You need a stop so that when you put something back in the vise it ends up in exactly the same place again.  You need V-Blocks which can come as matched pairs and are precision ground/machined which are used to hold round things.  And you still need other hold down devices for when the vise can’t be used.

So at this point you’ve added a few thousand dollars worth of stuff to hold things down and to measure/indicate things.  (Measure is to figure out exactly how big something is.  This is done via micrometers, calipers, scales and other measurement tools.  Indicating is to compare to readings in some way, for example knowing that this end of the vise jaw is 0.001″ closer to the spindle than the other end.)

Now that you have everything held in place you need a way to cut things.  This is done via tooling.   For a milling machine this is via end mills, fly cutter, face mills, drills, reamers, boring heads and bars, round overs, slotting saws, T slot cutters, woodruff key cutters and other things I don’t know about.

End mills are multi-point cutters, the are relatively small in size, less than 0.750 inches.  They can be center cutting so they can plunge straight into the work or they can only cut from the side.  They can have square corners or they can have rounded corners to live a fillet.  They can be used to cut a grove or widen one.  They can be used to completely surface the top of the work but it takes more passes with an end mill than a fly cutter.

A fly cutter is a single point cutter.  A cutting tool is inserted into the fly cutter and locked in place.  The cutter spins and exactly one point of the cutter touches the work.  Fly cutters come in many different sizes from 0.750 to over 2.000″ in cutting diameter.  They are designed to cut a small amount off the top of the work to make the top flat (and parallel to the table which should be parallel to the bottom of the vise jaw which should then make the work parallel to the bottom side if that bottom side is already milled flat)

Then there are face mills.  These are big honking things that have multiple cutting points and are designed to do the same job as a fly cutter.

So now we know that we need measuring and indicating tools, work holding devices, and cutting tools.  But some how we have have to be able to connect those cutting tools to the spindle of the milling machine.  This is done via a tool holder.  The type of tool holder I use is called an R-8.   This gizmo is an arbor that is inserted into the spindle.  First it is cleaned of all oil or other contaminants.   This is then inserted into the spindle (which should also be wiped down).  A grove in the side of the tool engages a pin inside the spindle.  This pin is there just to hold the arbor in place as it is pulled into the spindle.  At the top of the arbor is a threaded hole.  A long bar which has a hex shape on the top passes through the spindle and engages the threads in the arbor.  By tightening the draw bar the arbor is pulled up into the spindle.  When firmly seated the friction between the spindle and the arbor  is high enough to keep the arbor from spinning in the spindle as it cuts the work.

At the other end of the R-8 spindle can be many things.  The most common are end mill holders, collets, drill chuck arbors, arbors for boring heads and arbors for saws and shell mills.  A end mill holder has a precision hole in it which an end mill can be inserted.  A set screw is tightened to hold the end mill in place.  A collet has a hole in the very end as well, as the collet is pulled up into the spindle it squeeze the hole closed.   This means that it is very easy to change tooling which fits the collet.  Collets come in many nominal sizes which means that most standard sized round can be held very securely in them.

So now we have measuring, indicating, work holding, cutting tools, work positioning, and tool holders.  To that we need to add some optional but very helpful things.

The first is cooling.  As metal is removed by a cutter both the work piece and the cutter heat up.  To keep this under control the tool and or work needs to be kept cooled.  In the simplest way this is simply a squirt bottle or sprayer that allows you to put cutting fluids where they are needed.  A bit more extensive is using a misting system finally there is flood cooling.  Flood cooling is where the coolant is poured in a continues stream, often via re-circulating pumps.  The biggest problem with flood cooling is that the spinning tools will throw the coolant everywhere.  Mist cooling works a bit better but requires compressed air.  Using spray bottles works well to begin with.

After this is the power feed.   Most milling is performed via a back and forth motion of the table.  Each full rotation of the crank moves the table 0.200″ which means that to move the table 6 inches requires 30 full revolutions.  Even when the table is perfectly adjusted moving the table back and forth a few dozen times can get tiring.  At the same time if the speed at which the crank is turned changes then the surface might not have as nice of a a finish as wanted.

A power feed allows for controlled feed rate which is often very desirable as well as reducing the amount of effort it takes to complete a full operation.  (It is often the case that the cut is made at a slow feed rate but the movement of the table back to the start point is done at a much higher speed).  My machine has what is known as a “Mechanical feed” which has some parts which are damaged and should be replaced.  Unfortunately the part is no longer made.  Bridgeport doesn’t even acknowledge that the unit ever really exists.  Fortunately, anything on a Bridgeport that is not a casting can be made on a lathe plus mill.

The last piece of tooling for a mill is a DRO or Digital Read Out.  This consists of a pickup head attached to the stationary part and a “scale” attached to the moving part.  Thus for a 3 axis system there would be a scale attached to the table, the saddle and the knee.  The pickups would be attached to the saddle (to read the table location), the knee ( to read the saddle location) and the base/machine (to read the knee location).

The nice thing about a DRO is that it eliminates the problem of dealing with “backlash”.

Backlash is the “space” between gears and threads that exist in order to allow them to move freely.  You can see this by putting a nut on a bolt.  You should be able to wiggle the nut up and down a little bit as long as it is not snugged up to the end of the treads or tight against something.  This wiggle is backlash.  It can easily be a 10 thousands or more. 

Since the DRO reads exactly where the table is rather than how much the feed screws are rotated you can tell exactly where the spindle is relative to the table.  In addition a DRO is easier to read (big numbers on a display rather than small hash marks on a dial) and will often have special features to help with common operations.  (Bolt patterns, center of two points, automatic offsets)

Power feed units run a around $700 but might require a new lead screw which is a few hundred more.

Given a day to think about it another “tool” shows up.  A rotary table.  A rotary table is a table that clamps to the main mill table.  It can be turned a controlled amount.  Using a rotary table a circular path can be milled or a series of holes can be placed in a circle.  Drill a hole, rotate the table exactly 60 degrees, drill another hole.  Six holes later you have a “perfect” 6 hole pattern.

In addition a rotary table that can be placed vertically can be used to mill the sides of something or the top of something.  This would allow you to make gears or to make a hex at the end of a round bar.  All in all a very useful, if expensive, extra.

The lathe

I’ve been saying for more than a few months that the lathe is the most complex machine that I’ve ever used.  Just getting ready to use it takes time.  There are something on the order of 25-30 different points that should be oiled before starting work, not counting the ways.  There are 30+ different controls.

1. power switch, fwd, rev, off
2. belt tension lever
3. step belts
4. Bull gear engagement pin
5. back gear lever
6. power feed screw control: fwd, rev, neutral
7. high/low range feed screw control
8. high/medium/low feed screw control
9. tumbler control
10. carriage stop position clamp
11. carriage stop adjustment
12. carriage motion control
13. cross feed motion control
14. compound slide motion control
15. compound slide rotation
16. power feed clutch
17. power feed selector, carriage, cross feed, neutral
18. split nut control
19. threading dial positioning
20. Tool post rotation
21. Tool holder height adjustment
22. Tool holder clamp
23. taper attachment engagement clamp
24. taper attachment taper selector
25. tail stock clamp
26. tail stock positioning
27. tail stock quill control
28. tail stock quill lock
29. cross feed graduation dial setting
30. cross feed graduation dial lock
31. compound slide feed graduation dial setting
32. compound slide feed graduation dial lock
33. follow rest adjustments * 2
34. steady rest attachment and clamp
35. steady rest position * 3 
36. Chuck
    1. jaw selection (steps pointing in or steps pointing out)
    2. scroll control to open or close jaws OR 4 worm gears to close 4 jaw checks independently
    3. chuck selection
    4. clamping to face plate
    5. collet controls
    6. follow rest attachment

In addition to all of the above is tool selection.  We select tools for both the tail stock (drill chuck with the right bits, dead center, live center, bull nose center, half center, specialized center) and the tool post (cut off, turning tools (100s of choices), facing tools (100s of choices),  boring bars/tools (100s of choices), threading tools (internal, external, left/right handed, forming or not), indicator holders)

Well I think you get the idea…  There are lots and lots of controls and choices for doing lathe work.  Part of that is because you can do so much on a lathe.  Not only can you do turning but with the right attachments you can also do some milling work.

The Bench Grinder

It turns out that many things need tools ground to the right shape.  The bench grinder is used to shape High Speed Steel (HSS) to the right shape to cut.  These cutters are used in the lathe, in boring bars, in fly cutters.  In addition it is sometimes best to use the bench grinder to just grind a little bit more off of something to make it fit.

The Horizontal Bandsaw

It turns out that many many times you need to work with stock that is just about the correct size.  While small things can be fed through the lathe spindle larger things can not.  In addition a long rod in the spindle tends to bounce around.  The benefit is that you waste less because you can extend the rod out to working distance, do your work, cut off the piece, then advance the rod to repeat the operation.  This is quick, easy and wastes almost no stock.

If the stock is to big to fit through the spindle or just to long then it will need to be cut.  The horizontal bandsaw is the best tool for this operation.  A medium capacity saw will take stock up to 6×6 inches.  The one I happen to have takes stock up to 9×6.

While it might take a while to make it all the way through such a large piece of metal the bandsaw will eat its way through.  The biggest problem is when the piece is wide there is a huge surface area that the band moves across.  This makes it very difficult for the blade to cut.

The Vertical Bandsaw(missing)

While the horizontal bandsaw is the right thing for cutting bar stalk for cutting plate it often just can’t and when it can it is very slow and clumsy.  The vertical bandsaw can be used for cutting bar stock (bar stock is anything that is nominally small in cross section compared to its length.  Nominal because a piece of 8″ round bar stock 6″ long is still considered bar stock, even though it has a larger cross section than length)

A good vertical band saw will cut 1″ thick steel plate at a reasonable rate.  It goes much faster with AL and thinner stock.  The down side is that it normally will have a limited throat allowing a maximum length of 14-17″.  This is not normally an issue.

In perspective the horizontal bandsaw is normally used to cut stock for use in the lathe and the vertical for cutting stock to use on the mill.

The Shaper(missing)

This is a device that has a moving head with a single point tool.  The shaper head moves straight in and out.  On the back stroke the head is lifted slightly so it doesn’t touch the work.  At the end of the back stroke the work is advanced slightly to the side.  The head moves forward with the tool down and cut a single sliver off.  This is used to make things “flat”.

The Shear(missing)

This device is used to cut a piece of metal.  It can be used to cut bar stock or sheet stock.  As long as the piece fits in the shear and the shear has the capacity to cut it then the piece can be sheared.

In general the bigger the shear the thicker (and stronger) the material can be.  Thus a small bench mounted shear might only be able to cut through 22″ of 20 gauge mild steel while a “ironworker” with a 50 ton hydraulic press might be able to shear mild steel up to an 1/4″ thick and 40 inches long.

Steel mills use shears that can cut huge pieces of metal to size, often these shears operate on red hot metal (metal in the plastic phase)

Cutoff Wheels/Angle Grinder

A cutoff wheel removes metal via a grinding method.  A thin disk is spun at high speed and it grinds through metal.  Depending on the size and shape this can be fast or slow.  It is possible to cut through sheets and plates using this method if a bandsaw is not available.  In addition an angle grinder is very portable so can be used in places where a bandsaw can not.

Metal Addition

Unlike wood working in metal working you can add metal.  This is done with welding which creates a molten puddle of metal to which more material is added.  You can also use a method of spraying molten metal onto a piece of heated stock to build up missing parts.  Welding can also be used to connect two or more pieces of metal together.

Metal can also be fitted together so tightly that the become like one item.

Metal Forming

This is the process of deforming or bending metal.  It can be applied to bar stock or to sheet metal.  It can be done cold or hot.  A blacksmith does an extensive amount of metal forming.  By heating the metal to a plastic state and then hitting it the blacksmith can make the metal flow to different places.

Metal can be cold worked as well.  By hitting sheet metal with hammers with curved faces on top of wooden blocks with cups different shaped curves can be created.  Metal can also be rolled to create bends or run through rollers to make long straight curves.

Metal forming can bend, stretch, compress or create complex forms.

Metal can also be formed by pressing between two die.

Metal Casting

Where as in wood working you start with a tree and then remove wood till you get what you want, in metal you can liquefy the metal and then pour it in molten form into a mold.  Once the metal is cooled it is removed from the mold and then can be worked via other methods into a final result.

The most common example of this is a cast iron pan.  With this a mold is made and molten iron/steel poured in.  After the metal is cooled the excess metal is removed and you have a pan ready to use.

More complex objects are often cast in pieces, the pieces are then machined and the machined pieces connected together.  A common example of this is the block from a car engine.

Metal casting is a multi-step process.  In general it consists of making a pattern.  Making a mold of that pattern.  Potentially removing the pattern from the mold.  Melting the metal.  Pouring the metal into the mold.  Then extracting the finished product from the mold and finally removing the excess metal.

There are three major types of pattern/molds:

• Reusable pattern
• Lost pattern
• Reusable mold

With a reusable pattern a frame is placed over/around the pattern.  A special mixture of clay, sand and water is packed around the pattern.  The frame is flipped over and another frame carefully placed on top of the first frame.  More sand is packed (rammed) into the frame.  Holes are cut to allow molten metal to reach the pattern and vent holes added to make sure that any gases generated during the pour can escape.  Finally the two frames are opened up and the pattern removed for use later.  The two forms are put back together in preparation for the pour.

With a lost pattern a pattern is constructed and then put into a frame.  The sand mixture is packed around the pattern.  The holes are cut for the metal to be poured into.  When this is done either the pattern is cooked out of the mold or it is left in place to be destroyed by the molten metal.

Lost wax is using a pattern made from wax.  The mold is cooked and wax melts and is poured out the fill holes.  When the molten metal is added the remaining wax is burned off.

Lost foam patterns are just left in place.  When the molten metal hits the foam the foam is destroyed/burned off.  You can see this process by applying a flame to Styrofoam.   The foam, as it melts, takes up much much less space and the small amount of material left behind is rapidly destroyed/burned off by the molten metal.

Reusable molds are designed so that they can survive molten metal being poured directly into them.  The two (or more) parts of the mold are connected together.  The molten metal is poured in.  When the molten metal is removed the molds can be quickly cleaned and reused.  This method could be used for example to cast aluminum items in cast iron molds.

In order to cast an item a mold has to be constructed.  The type of mold that I’m interested in is called “green sand” which means it consists of a frame, called a flask, which is packed (rammed) with a sand, clay, oil/water mixture.  The sand used is normally very fine and when it is properly mixed you can take a clump of it squeeze it in the palm of your hand and then see your palm print in the clump.  The clump will hold this shape and when stressed will break cleanly rather than crumple into pieces.

Most flasks are two pieces but there are flasks that have more than just two pieces.  A very simple pattern, one with a flat surface, is placed on the molding board.  Parting dust is distributed over the pattern. The bottom flask, called the drag, is placed over the pattern.  The green sand is then passed through a sieve into the drag until the pattern is partially covered.  This removes any big clumps are left over bits of metal from the last pour.

Once there is sand in the flask a ram is used to tamp down on the sand, compressing it.   More sand is added and rammed up.  A big flask will have ridges around the inside to help grip the rammed up sand.  Filled flasks can be very very heavy so it is important to use the right sized flask.  Once the drag is filled to the top a straight edge is run across the top of the flask “striking off” the sand that extends over the top edge.  This gives a flat surface.

The drag is then flipped over, a parting dust is sprinkled over the entire exposed drag top.  This is the green sand and the pattern.  The top of the flask, called a cope, is then placed over the drag.  There are normally aligning pins to make this happen in a repeatable way.

If it is a simple pattern then sand is sieved over the pattern, rammed up, then more sand is added until the cope is full.  The cope is then struck off.  A sprue cutter is then inserted to cut a hole down to the parting line (the line between the cope and drag in the sand).  A small well can be formed with a spoon or knife to make a funnel.

If the pattern is big enough a riser will be added as well.  This is just like a sprue except it will be filled from the bottom instead of the top.  I.e. molten metal is poured into the sprue, fills the space where the pattern exists and then continues filling the cavities including the riser.  As the metal cools it will contract sucking metal from the sprue and any risers to keep the pattern full of metal.

After the sprue and optional riser(s) are cut and the sand removed the cope is lifted off the drag and put upside down on the molding board.  The parting dust helps keep the sand from the drag from sticking to the sand in the cope.  Sort of like flouring a cake pan to help the cake come out of the pan without sticking.

Once the cope is separated from the drag runners are cut by hand from the sprue and riser(s) to the pattern.  The runners need to be large enough that the metal flows quickly and freely from the sprue to the pattern cavity and from there to any risers.  The depth of the sprue should be slightly deeper than the depth of the runners.  This way any sand or junk that gets knocked down the sprue is left at bottom of the sprue and not carried into the casting proper.

At this point the pattern is removed from the drag.  Normally there are a couple of small holes in the bottom of the pattern.  A screw or eye screw is carefully threaded into these holes.  The screws are then gently rapped to loosen the pattern in the mold and then the pattern is carefully lifted out leaving a cavity behind.  Any sand is carefully removed, never with compressed air.  As one pundit put it: Using compressed air is a good way to get all of the sand out of your flask and all over the work shed.

Anything that is wrong with the cavity that can be repaired by hand is now down.  If the cavity isn’t right it is time to knock out the sand and start over again.

Once the cavity is right in the sand the cope is lifted up and flipped over again to be carefully realigned with the drag.  This means that the sprue and risers will correctly align with the runners cut in the drag.

At this point more molds can be made up and when all of the molds are ready they are moved to the casting area.  The casting area needs to be free from moisture and the top of the sprue has to be lower than the height from which the metal will be poured.  I.e. don’t put the flask on top of your table and then expect to lift 10-30 lbs of molten metal in crucible high enough to pour smoothly.

Note: Aluminum weighs in at about 5lbs per qt (5.2359787 lbs/liter at 661C) and Iron is around 15 lbs per qt (15.388266 lbs/liter at 1538C).

Now that the molds are ready it is time to melt some metal.  The furnace is started and a crucible placed inside.  Ingots or scrap metal is then added to the crucible a little at a time.  You don’t want to add the metal so rapidly that the pool of already molten metal cools so much that it solidifies.

At this point some things are added to the molten metal to declassify it and to make any impurities rise to the top.  These impurities are scooped off and put to the side to be discarded later.  The crucible is then lifted out of the furnace with lifting tongs.  It may be transferred to a pouring device or the tongs themselves be used for pouring.

The crucible is then positioned over the sprue and the metal is quickly poured.  The metal will immediately start to cool as it comes in contact with the “cold” sand so the pour has to be rapid enough that the molten metal can get everywhere it needs to go with out solidifying.  This is why it is hard to cast thin items.  The metal solidifies before it reaches all the parts of the pattern cavity.

Once the mold is filled the crucible can be used to fill other molds or returned to the furnace for more metal to be melted.   The important thing is that when the pour is done ALL of the metal in the crucible needs to be poured out.  Often the metal is poured into ingot molds for use with the next melt.

The metal is allowed to cool to make sure it is completely solid and a bit more.  There is no reason to rush this process.  Finally the flasks with molds and metal are moved to the knock out area.  Here the casting is removed from the sand and as much sand as possible is recovered for reuse.   The castings are brushed and poked and prodded until as much sand as possible is cleaned from them.

When the casting is cooled enough the runners are cut off which also removes the sprue and risers.  This metal is returned to the raw metal for use in another melt.  At this point the raw casting is either sent to finishing or to the machine shop for machining.

Finishing would be using buffers and grinders to remove the last of the runners.  This is all that needs to be done for things like cast iron pans.

One of the first castings I hope to attempt is to make a cast aluminum pan.  I’ll use one of my current cast iron pans as the pattern and then cast the aluminum equivalent.

Pattern Making

Pattern making is the art of creating something that will create the correct cavity in a mold.  The requirements are simple: The pattern needs to be able to be placed into the flask and rammed up then removed without destroying the cavity in the mold.  In addition the pattern needs to make correct support cavities to hold any cores that are added.

Consider a simple casting that has an axle that goes through it.  The pattern could be made such that item is cast as one solid piece.  After that casting is sent to the machine shop and the hole for the axle will need to be drilled and then bored to size.  Most of the metal that is removed during this process is likely to be lost.  Collecting chips is a pain and they are often contaminated with oils and cutting fluids.  They might also be contaminated with different metal.  You really don’t want to have steel/iron chips in with your aluminum.

I’m sure that using magnets would work to some extent but it would be a lot of work.  Normally when metal recovery is going to be done the mill/lathe is cleaned of all other metals and then the milling takes place.

Regardless, the fact of the matter is that having to machine a complete bore through a casting is time consuming and a pain.  In some cases it is impossible without special drills to make the hole deep enough to go from one side to the other.

Thus is born the “core”.  A core is merely a casting in sand or other material that can be placed in the cavity created by a pattern to make the hollow.  In the example at hand the pattern would have to cylinders attached where the axle would go extending outward.  This would create a hole in the mold at both sides.  The core, which looks like a rod, would then be placed between these holes filling in an area where the axle will go.  Now when the mold is closed over the core and molten metal is poured into the mold it flows around the core.

When the mold is opened and the casting is removed the core can be removed as well.  This is sometimes done just by soaking the casting and core in water.  There are a couple of ways of making these cores, one is with “liquid glass” another is with a mixture of grains baked in the oven.  It doesn’t really matter how the cores are made as long as the are self supporting and can be removed after the fact.

In some cases people will use steel rods as cores in aluminum castings.  After the casting cools the steel rod is pressed out of the casting.

Besides cores patterns can also be made in parts.  The simplest is the “split pattern.”  Again using our example of an axle housing

(The article was unfinished, and ended here.)

Chris wrote this article on Aug 17, 2013.

A knurled knob and lug to stud adapter. Made by ME!

A few weeks ago I bought a metal lathe and milling machine. I’ve slowly been collecting tools and material to actually accomplish something. Mostly I’ve been cleaning, oiling adjusting and just getting everything “just right”.

One of my latest purchases was this indicator holder, it is held in a regular or quick change tool holder and is designed to attach to a stud on the indicator.  If you look at the fuzzy picture of the indicator you can see one “stud” which is at the right.  But it is way to big to fit into the clamp on the holder.  It does turn out that the stud at the top is the right size but I found that out after I was mostly done.  And I’m not sure I would use it as it is very short.

On the back of the indicator is a “lug” which is this loop thing on the back.  That isn’t very helpful by itself.  Of course there are adapters to put a stud into the lug so they can be attached.  I went to my two different indicator holders and pulled out the stud adapter and attached it to the indicator.

Here is the adapter attached to the indicator.  The knurled nut is tightened and that locks the stud in place.

Unfortunately there is a problem with this adapter, it is the wrong size!  It is too big.  It does not fit into the holder.

I did try but the clamp does not fit.  This gives me two choices, make a larger clamp which is primarily a milling operation on steel I don’t have or make a new stud adapter.

The first step is to draw a picture and measure everything.  The stud has three parts, the stud, the lip on the stud and the threaded part.  I measure all the parts and then go to figure out what size thread it is.  And it isn’t any normal thread.  My gage refused to identify it.  And the size doesn’t match anything I have.  Let’s think for a moment, oh yeah, I bought this from Grizzly which imports 99% of its stuff which means it must be *metric*.  15+ years ago and 6 moves ago I bought a set of metric taps and dies.  Since that time half the dies have gone missing and all the taps.

I go to double check and it turns out that there is exactly ONE tap remaining… And the gods shine on me it is the right tap for this thread and I have a matching die for it.

On the drawing I have the sizes of the original and then off to the right the range of sizes that the clamp supports.  So now it is time to start the process of making my stud adapter.

I start with the stud piece.  First I put a piece of 1/2″ 12L14 steel rod in.  The end is faced and then I use Dykem blue for the first time and mark the location of the shoulder.  With the new tooling it is turned down to size quickly and easily.  To easily.  The first attempt I turned the stud to small and had to cut that part off and throw it away.

2nd try and the stud ends up exactly the right size.  I test it in the clamp and it is a perfect fit.  Yeah!!!!  Now that I’ve completed the stud I cut it off to length, flip it around face it to length.  The finished surface is protected from the chuck jaws with a piece of 0.005 thick brass shim.  After it is faced I mark the shoulder and turn the threaded section to size.

Done with that I cut the threads with a die.  Unfortunately it is a cheap die and it rips one thread but there is enough left to work.  A few touches of the file and the sharp, finger cutting, edges are broken and it looks finished.   I test with the original knurled knob and it works!  Yeah.

For the next two hours I stare at the knob trying to figure out the order of operations for the knob.  If I cut the small section I won’t be able to hold that in the chuck safely and turn the rest of the piece.  In addition I don’t have a piece of rod the right size.

The answer finally hits me.  Step one I put a piece of 1″ rod in the lathe and mark for a shoulder.  I marked it for 0.750 but I should have made it a bit further.  No real problem

Next I turn the rod to the larger diameter.  0.540 inches.  And I got it right within 0.0005.   Then it is time for a tool I’ve never used before, the knurling tool.  The wheels of the tool are pressed hard into the metal rod and if it is adjusted correctly it cuts a beautiful knurl.  Of course I adjusted it incorrectly to begin with.  I got it right and was able to cut a knurl.

I now have a knurl but I need to cut the relief.  No problem.  I just turn to size and clean up the shoulder, break the corners.  Then I center drill the piece, drill for tapping.  I should have drilled the clearance hole next but I waited on that.

I tapped the hole and that worked wonderfully!  I know have a 4 ft section of 1 inch rod with a knurl at one end with a hole drilled and threaded.  Out comes the cutting tool and I part off the knob just a little long.

And then my break through… I thread the knob on to the stud, remount the stud with the protective shim and quickly face the knob to size, cutting the screw to length at the same time!  A quick touch up of the corners with a file and the knob is finished!

Last step, take the knob off and touch up the end of the screw with a file to make that edge gentle and finished.


Only about 2 hours to make something that likely would cost me less than $5.00, if I could find it.  Well worth it!