Hello all, Last year I discovered that any carbon-filled material allows one to print parts with machine screw threads that are usable. It occurred to me that this might not be common knowledge. Actually, I can't believe how well it works. I've successfully incorporated the technique on most of my recent projects with thread sizes as small as M2.5 when oriented vertically on the build plate and as small as M4 for horizontal holes. In general, the threads are strong enough that I can tighten a screw as tight as I can by hand when grasping the smaller leg of a hex key, and can usually go a bit further tightening with the long leg of a hex key. It's pretty amazing... a stainless screw will tighten to a squeak. I understand this might be unbelievable to some, so here's an STL of a test article with two M5 holes in it if anyone wants a quick way to try it: [www.lightsmithscientific.com] The build orientation is important as I use different thread geometry for vertical and for horizontal holes. The filleted edges indicate the X-Y plane. Here's a photo of a part that makes use of it: [lightsmithscientific.com] I incorporate the thread geometry into my models by keeping a library of cylinders with just the threads in them, which I call "thread features" in my brain, and the OD of these cylinders is the same as the clearance hole diameter for that thread, which is a convenience. The parts that will get the threads just have clearance holes modeled where needed, and then I add the thread features in an assembly. From that I generate the STL, and run it through the Netfabb fixer service to heal the boundaries. I'm curious to hear if anyone else has played with this. ~Justine https://reprap.org/forum/read.php?1,792147,792147#msg-792147 Tue, 08 Sep 2026 23:53:04 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,792147,792268#msg-792268 https://reprap.org/forum/read.php?1,792147,792268#msg-792268 Origamib General Sat, 14 Oct 2017 13:07:16 -0400 https://reprap.org/forum/read.php?1,792147,792170#msg-792170 https://reprap.org/forum/read.php?1,792147,792170#msg-792170 DjDemonD General Fri, 13 Oct 2017 13:25:42 -0400 https://reprap.org/forum/read.php?1,792147,792147#msg-792147 https://reprap.org/forum/read.php?1,792147,792147#msg-792147
Last year I discovered that any carbon-filled material allows one to print parts with machine screw threads that are usable. It occurred to me that this might not be common knowledge.

Actually, I can't believe how well it works. I've successfully incorporated the technique on most of my recent projects with thread sizes as small as M2.5 when oriented vertically on the build plate and as small as M4 for horizontal holes. In general, the threads are strong enough that I can tighten a screw as tight as I can by hand when grasping the smaller leg of a hex key, and can usually go a bit further tightening with the long leg of a hex key. It's pretty amazing... a stainless screw will tighten to a squeak.

I understand this might be unbelievable to some, so here's an STL of a test article with two M5 holes in it if anyone wants a quick way to try it: [www.lightsmithscientific.com]

The build orientation is important as I use different thread geometry for vertical and for horizontal holes. The filleted edges indicate the X-Y plane.

Here's a photo of a part that makes use of it: [lightsmithscientific.com]

I incorporate the thread geometry into my models by keeping a library of cylinders with just the threads in them, which I call "thread features" in my brain, and the OD of these cylinders is the same as the clearance hole diameter for that thread, which is a convenience. The parts that will get the threads just have clearance holes modeled where needed, and then I add the thread features in an assembly. From that I generate the STL, and run it through the Netfabb fixer service to heal the boundaries.

I'm curious to hear if anyone else has played with this.

~Justine]]> justine.haupt General Fri, 13 Oct 2017 09:42:51 -0400