If you look, there are several YouTube channels that are discussing Thursday’s oral arguments in front of the Ninth Circuit. The tea leaves suggest that the three judge panel will not issue their opinion until after the en banc issues their opinion on Duncan v. Bonta. The panel did not ask questions that make you feel like The People will win this case.
I am continuing to work on the Casinator
Mostly my issue has been in learning something about drafting. Stupid things like how to layout dimension lines. What the correct size is. How to do hole callouts.
Many things. And don’t get started on GT&D. That is a nightmare but useful.
I recently started using a “highlighter” on quotes. Is that helpful to you?
Here’s hoping you all have a great weekend.
Comments
8 responses to “Friday Feedback”
I R a drafter. Any questions I can answer?
I do not know what I don’t know. My goal, at first, was to create something I could machine from. I’ve watched some videos, I’ve read some pages, I’ve worked with other peoples drawings.
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What I would like, is for you to “red pen” my work. That is to say, tell me what I did wrong.
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In particular, did I size the balloons correctly? They look huge to me. Are my dimensions positioned correctly? How do I indicate that the four bearing pockets are on the same centerlines without making the diagram too busy. Do I need to have “3x M3 ↧ 6mm” for each edge or can I just say “9x M3 ↧ 6mm” Once?
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Any feedback would be wonderful! Thank you.
SVG version
DXF version
PDF version
Please ignore the bad hashing on the SVG, that is an issue with FreeCAD. I just looked at the DXF and it doesn’t have dimensions.
I’m mobile right now, but I can do that. First impression, double your scale and use the page better. Right now you have a lot of overlap. A cardinal sin of drafting is lines going through text. You can say M3 6mm DP, TYP as long as they are distinctly sized and can’t be mistaken for a similar looking feature. Diameters are always shown as a single leaderline that would extend to the center of the circle if they didn’t terminate at the edge of feature. You do have the theta symbol so that’s good. Your dimensions are too crowded overall. Standards state 1/2″ between them on the paper. Text is 1/8″ for hand and .1-1/8″ for CAD normally. You’ve got 3 digit decimals on everything. That implies a tolerance of +-.0005 for every dimension. Any machinist is going to smack you for it. Drop to .xx for anything except highly critical things. Backview(2nd from right) you’re missing a dim to locate the holes vertically. Left view, you have your centerline linetype wrong. You also need to explicitly call out centerlines from one edge, because in the real world, the machinist will use an edge as a baseline. Also, make sure you use the same edge so that as the part is rotated, the baseline edge remains the same, otherwise if you alternate sides, you may have features that are off by up to double the tolerance, but otherwise in tolerance. You call out a countersink of 90 degrees, intentional? Most countersinks are 82 degrees to match a fastener. Your section view callout linetypes should be phantom, not hidden. I’ll take a better look when I get home tomorrow. Shoot me an email reminder.
I’ve doubled the scale. I’ve made sure that no lines cross text. The hole callouts now point to the center of the hole. The diameter dimensions are across the hole. I’m using the Depth symbol and the countersink symbols. I’ve changed the spacing on the dimension spacing. Text is now 0.125. I’ve moved to a 2 digit except where the is a tolerance required. I might be stuck on the centerline with this version of FreeCAD. I don’t understand “explicitly call out centerline from an edge? Are you saying to put a dimension from the datum to the center line when a center line is provided? Wouldn’t the dimension of the perpendicular give that? I.e. 0.25 is the thickness of the plate. A center line would be at 0.125 and no need to add more information.
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Yes, I messed up my datum moving from front to back. How do I indicate a datum point? On the faceplate I have two datum points. Lower left corner of the front, and then the center of the lower left bearing pocket. That is because the spacing of the idle hole and bearing pockets are more critical relative to each other than they are relative to their location on the plate.
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I looked up ISO countersinks. They are 90 degrees. ANSI is 82 degrees. I might be wrong, but that is what I pulled of the net. Maybe I just pulled a strange version of ISO countersinks.
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Callout linetype should be phantom. I’ll look up the line pattern for that.
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Wow, thank you. I’ll hit you up with an email tomorrow.
“I don’t understand “explicitly call out centerline from an edge? Are you saying to put a dimension from the datum to the center line when a center line is provided? Wouldn’t the dimension of the perpendicular give that? I.e. 0.25 is the thickness of the plate. A center line would be at 0.125 and no need to add more information.” In theory and in CAD, you would be correct. In the shop, the thickness of the plate will vary up to your tolerance and the machinist will be measuring off one face or the other. If your thickness tolerance is +- .005 and your hole location is +-.005 and he uses the front face for the top and the back face for the bottom because of how he flips it, the top and back holes could be off by .02(.005+.005+.005+.005) relative to each other, yet still be in tolerance. If you index the centerline from the front face in every view, you put the holes into the same tolerance bracket so you take +-.01 out of it right off the bat.
I appreciate the effort to highlight, but on my screen it’s barely perceptible; I have to tilt my screen or otherwise change my viewing angle to see what’s been highlighted. I’ll play with settings, but is anyone else having that issue? Is it possible to make it a bit more prominent?
For my settings the highlighting is a good shade, especially against the generalized section background. As you adjust to brighten for those who see the highlighting more dimly, PLEASE stop short of slap-in-the-face-bright almost fluorescent versions! And thanks for the added direction, especially as I tend to easily get lost in legal explanations no matter how clearly you write them. MY issue, not yours. The VA eye clinic has pretty much given up on me and at my age I can’t fault them for it.
The thing you are going to need to deal with is how to manage tolerances and tolerance build-up. GD&T is one approach; there are multiple ways to approach the problem and all have their pros and cons. Remember that not all tolerances need to be tight – make each dimension as tight as it needs to be and no tighter. Tight tolerance = higher cost. Quality control is where you can get a perspective on how to dimension things – think about how you convey to an inspector what to check.
Start with what tolerances your cases can have to begin with and then determine what the final tolerances on the finished case can be. Work backwards from there to the individual components.
As you are finding out drafting isn’t a simple topic.