Thread optimized for 3D printing

Why use a thread optimized for 3D printing?

Little screws are ideal to assemble multiple parts of 3D designs and to mount them to your workbench. (For example this tape dispenser or this angle bevel). But smaller standard threads, like M4, M5 or M6, are difficult to print reliably with a standard 0.4mm nozzle. 

It is possible of course to tune the size of the screw and the nut on a particular printer to make M4 or maybe even M3 work together. For reliable designs that everyone can reproduce, this specially optimized 6mm wide thread is ideal. It replaces the 1mm pitch and 60° thread angle of a metric M6 thread with a 1.5mm pitch and a 90° thread angle (means 45° flank angle = 45° overhang, which is much better printable then a 30° flank angle = 60° overhang).

The mechanical play between screw and nut in this design is carefully tuned. I did compatibility tests between different printers and different filaments. All did fit together well.

Standard parts that are ready to print

• Torx head screws, 6-20mm long, with a head that is also optimized for 3D printing (a regular Torx T30 metal tool will fit or you can use this 3D printed Torx screw bit)
• Round head screws, 6-20mm long, just use a flat screw driver
• Hex head screws, 6-20mm long, with a 10mm head (M6-like), be gentle when tightening with a wrench
• Hex nut
• Wing nut
• Ring nut
• Thumb nut

How to use it for your own designs

These screws, nuts, threaded rods and thread inserts are free to be used in your own designs (under a remix-allowing license). So feel free make them part of your own designs. 

While the screws and the nuts are intended for usage as-is, the idea behind the inserts and the rod is that you can use it as part of your designs. I actually use the thread inserts myself when I design parts with internal threads. I simply leave a somewhat bigger bore in the parts and melt a thread insert with the part. That keeps the design modular and easy to modify. 

Printing

All parts should be printed in the uploaded orientation with a layer height of 0.15mm. 

I recommend at least 4 perimeters to make the threads nice and strong. Infill is not critical if you use enough perimeters, I recommend 40%, as less is pretty pointless for such small parts.

No supports are necessary on any of the parts.

A standard 0.4mm nozzle works fine, it was my point to create threads that do not need an extra fine nozzle to work well.

Both PLA and PETG have been tested successfully, but keep in mind that PLA “flows” over time when it is under constant mechanical tension. PETG is clearly the better choice for long term usage. 

Scaling to larger or smaller sizes

Of course it is no problem to up-scale all these parts. However, they are most valuable at smaller sizes, as much larger threads also print nicely in standard dimensions (For example, a M16 screw and nut does print perfectly fine with their 60° flank angle).

Let me know if you manage to successfully down-scale these parts significantly. I could imagine that at 4mm (⅔ of the original) it still might work reasonably, but 3mm (½ of the original) is probably the borderline. I have not tested either, as I believe 6mm is the size that give reliable and reproduce-able results, so I stuck to that.