I have a question: when making a drawing of a disk shape for machining, is it sufficient to draw only one-half of a cross section (with dimensions, of course)? Or, should one draw both cross-section halves, but only dimension one of them?

It's probably best to ask the place doing the machining, but if the part is symmetrical, I think it might be ok to do one half.

@jmwright Thanks for your thoughts. So far, I have sent my (hard-won) DXF file to five local shops, three days ago. Are they too busy? Maybe it is a character flaw, but I am impatient at being ignored. I will send to, at least, a dozen more Monday morning.

I posted that same question to the Autocad community on G+ two days ago. If anybody is familiar with mechanical drawings, they are. Ignored again.

Machine shops will usually prioritize larger jobs with companies over smaller jobs with individuals. It can be hard to get their attention. They're usually not trying to be rude, but it can still be frustrating from our perspective.

@jmwright Well, after weeks of waiting, I finally got my aluminum part (the top) from a local machine shop. Now I can make a mold to make duplicates from glass-filled epoxy. Still a lot to do.

I'm looking forward to hearing how the epoxy molding process goes. Will the magnets be molded directly in, or put in later somehow?

@jmwright The plan is to place a fasten the magnets after the base part is cast. I need to build a fixture to coax the tiny N52 neodymium magnets to sit in a neat row while the epoxy sets up. One of many rabbits to pull out of a hat.

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