[ Ref. John Grant in 220623 MMDigest

 [ I wrote to my friend Eric Varsanyi about this inquiry. Eric is
 [ a software engineering buddy of mine that I've known for over
 [ 20 years (yikes!). He is very active with 3-D printing as well
 [ as numerically controlled machining of wood and metal. He has
 [ designed and built many electronic gadgets, including designing
 [ his own circuit boards. Many of these have ended up in 3-D
 [ printed enclosures which led me to contact him about this inquiry.
 [ -- Jody

Those are plastic screws; I use that category to attach PCBs to 3-D
prints. Is it the plastic aspect, or the length with the extra shank,
that he's after?

If you search for plastic screws on McMaster Carr, there are zillions
of them. I use these cap head screws for a lot of stuff:

https://www.mcmaster.com/screws/for-use-in~plastic/high-strength-410-stainless-steel-rounded-head-thread-forming-screws-for-brittle-plastic/
Thread-Forming Screws for Brittle Plastic

The subcategory I prefer are the self tapping screws -- I print the
appropriate smooth pilot hole and it's all done.

For a more reusable or high use/strength setup I really like the
threaded brass inserts you melt in with a soldering iron:

https://www.mcmaster.com/inserts/tapered-heat-set-inserts-for-plastic-7/ 

Eric Varsanyi