- Joined
- Dec 18, 2019
- Messages
- 6,447
Making subtractive threads on FreeCAD seems to be an adventure. I think the best thing to do is to use threaded rods from Fastener workbench as male forms and perhaps use them as "taps" and using a boolean cut for the female ones. I have been having fun trying to successfully model an adapter with a lot of threads in it. I have a 3/4-20 thread, a 1/2-20 thread and a 0.5mm thread. Yeah, I should change the 0.5mm thread to something like 40 TPI, so it won't be so hard single point threading. Keeping it imperial makes the single pointing a little more enjoyable, since I could use the thread dial.
Anyways, been having fun with subtractive helices, and have come up with something like this. It's an adapter. The 3/4-20 threads into a printed moderator. The 40 TPI threads thread into a carbon fiber tube. The carbon fiber tube surrounds the 3d printed moderator. A steel male thread (from a barrel or barrel adapter) screws into the internal 1/2-20 thread. Sort of looks like this. I do realize that most CAD drawings don't render the threads. Or at least one's that aren't to be 3d printed. The CAD engine really has troubles with these helices. It gets fouled up, which strangely doesn't effect the 3d model itself, but when you try to get 2D projections, as in TechDraw, the software fails to correctly generate proper section views. There's a fine line between working and not working. It's taken the better part of a week to get the cross sections to display correctly.
It could be I'm just doing this the wrong or hard way, but so far I haven't yet found the right/easy/foolproof way to generate drawings for these kinds of parts. There's a few nuance that I seem to be missing. But, I'm still plugging away at it. Eventually, I'll get there.
Can't say it has been fun, but I have learned a few new techniques along the way, so it is not all bad.
Anyways, been having fun with subtractive helices, and have come up with something like this. It's an adapter. The 3/4-20 threads into a printed moderator. The 40 TPI threads thread into a carbon fiber tube. The carbon fiber tube surrounds the 3d printed moderator. A steel male thread (from a barrel or barrel adapter) screws into the internal 1/2-20 thread. Sort of looks like this. I do realize that most CAD drawings don't render the threads. Or at least one's that aren't to be 3d printed. The CAD engine really has troubles with these helices. It gets fouled up, which strangely doesn't effect the 3d model itself, but when you try to get 2D projections, as in TechDraw, the software fails to correctly generate proper section views. There's a fine line between working and not working. It's taken the better part of a week to get the cross sections to display correctly.
It could be I'm just doing this the wrong or hard way, but so far I haven't yet found the right/easy/foolproof way to generate drawings for these kinds of parts. There's a few nuance that I seem to be missing. But, I'm still plugging away at it. Eventually, I'll get there.
Can't say it has been fun, but I have learned a few new techniques along the way, so it is not all bad.
