j4k3@lemmy.world 1 week ago
Printing like this is a fun start on the path of thinking about what is possible.
In FreeCAD, there is Mark’s Thread Design workbench. That includes a thread profile called the buttressed three. The profile has a print orientation where, if you print it vertical, the thread will not produce any overhangs, like if a normal thread profile is > a buttress thread is 7. Mark has a YT upload on how to use his workbench. It is pretty easy to follow and a simple one to use.
At the stage I’m at in design, built it clips can replace most hardware. If I’m using printed threads it is usually a very large thread with some thin sleeve like clearance. I like to build splines into my threads to also create locking elements in the same space.
Bluewing@lemmy.world 1 week ago
Having single pointed 3"-4 Buttress threads on a manual lathe for punch presses more than once and hand grinding the tool bit from 1/2" x 1" HSS, I still have some PTSD over that thread form. But hey, if you are looking to make breaching for a 16" Navel Rifle, it’s really the only game in town…
As a toolmaker, I have seen Buttress threads used in only 3 places. Large artillery breaching, punch press ball screws, and VERY high end, (read expensive), machinist clamps. I own a pair I picked up at an auction 30 years ago in a bucket of “junk”. I think they were made by another machinist for personal use.
j4k3@lemmy.world 1 week ago
Thanks so much. I did not know the original purpose of the profile. In my experience with 3d printing, the buttress profile strength is in the opposite orientation when printed vertically. The additional length of the tapered profile creates a better distributed load across more layers of the stretching member/faster. Still, I will prioritize overall printability without supports over thread directional orientation in most cases. I’m usually using a very large custom sized thread where the thread strength is irrelevant.
Like here in my laptop GPU water cooler project, I am using a buttress thread and spline to retain the cooling block and pump.
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Bluewing@lemmy.world 1 week ago
At that diameter, I would probably recommend a bottle cap thread. It’s a rounded profile that is easy to print.
j4k3@lemmy.world 1 week ago
Walls are too thin for a bottle and with the cut for r&i I would expect it to have issues at the seam. Even with this, the seam requires holding until it starts to get touching contact. Maybe if the bottle is extended past the 45°-50° tangent it would do a little better but then it has drop potential, especially with this PC/ABS blend and no part fan in an enclosure.
Pulptastic@midwest.social 1 week ago
I worked at a shop that made large hydraulic cylinders and some of them used buttress threads.
Bluewing@lemmy.world 1 week ago
I’ve seen hydraulic cylinders up to a mere 150 tons, but they both used vee threads. But those cylinders can had far,far bigger than that. That would be a very good application of buttress threads. Much like the balls screws on a punch press. Lots of force in one direction.