T-nut with M5 thread for Prusa Mini extrusions

Design history

This design is based on my original T-nut for the Pursa Mini profile, which again was based on the dimensions of commercial metal T-nuts that are offered on the internet. I was impressed myself how strong this printed T-nut came out. The design became very popular over time, despite that fact that it did not have a printed thread. 

By the time of the design I was reluctant to print such a small thread. And frankly, I was also missing the needed expertise and experience with threads. Since then I have done a lot of designs in FreeCAD with threads, so I felt ready to upgrade the design now. 

I have put quite a bit of experimenting in finding exactly the right dimensions for the M5 thread. For a T-nut it is important, that the screw has a bit of resistance within the nut. That is not the case the for most metal T-nuts, which makes them a real pain to use. This design however (when printed on the Prusa Mini from PETG) has just the right resistance to be used without any fiddling. 

Printing instructions

For a perfect thread, print this design standing upright (screw thread in Z-axis direction). In that case I recommend to print with brim and cut it of with a knife after the print. 

I recommend to print this design in the uploaded orientation (laying on the side), if you need ultimate strength (reduces stress on layer adhesion). The thread works surprisingly well also in this orientation, but I feel that the thread is even stronger when printed in the upright orientation. No brim is needed if you print the parts on their side.

There is clearly no support needed to print this design, both in upright and side-down orientation. 

To get the most perfect print, I recommend to print several parts at a time, to give each layer time to cool.

For such a tiny part, I guess it goes without saying that you should print it with 100% infill. 

A normal 0.4mm nozzle works just fine and also the standard layer height of 0.15mm gives very reasonable threads. As the pitch of a M5 thread is only 0.8mm, I prefer to spend a bit more time for the print and use a 0.10mm layer height (which results in 1h40m print time for 9 pieces at a time on a Prusa Mini).

Please Like it if you like it 

If you like this design please give me a thumbs-up. And don't be shy to share the pictures of your use-case around the Pursa Mini, whatever that might be. 

Happy printing!