Designed in FreeCAD. I wanted to make a customizable screw and nut for my designs. Took me (on and off) weeks to get this working. But now that it does, I kind of want to test it to see how strong it is.
That screw is nuts
If you want to create threads in FreeCAD, install the fasteners workbench. It makes it much easier and it has a setting for creating 3D printable threads.
I wanted an easy design which can be applied. While the fasteners workbench is neat, it’s not what I am looking for.
That is a mighty chunky thread!
I can tell you from experience that the strength of your part is not likely to be due to the design or pitch of the threads but rather down to the layer adhesion strength of your print and whatever material you’re using. Even a dinky 1.0mm thread pitch is perfectly capable of ripping the layer lines of a print apart, and your point of failure will be the layer immediately below where your countersunk head contacts the base of your nut and/or part it’s screwed into, the exact moment you overtorque it.
I have a bit of experience with this sort of thing. Actually, these days, probably rather a lot.
Your thread creation approach is similar to mine but I prefer to use an additive helix on the male thread, and then a matching subtractive one on the nut or female side. I find this makes it a little easier to tune for good engagement. If you need to make multiples in a single assembly you can draft clone your sketches to make them all the same. Change one, change them all. You can just use triangles to create both the male and female helices, unless you want to make the tips of the threads flat in which case you can draw a trapezoid.
There are various threaded fastener workbenches and plugins available, as others have mentioned, but I prefer to do things the hard way since I came up using FreeCAD in not only the pre-1.0 era, but even pre-0.21 back when the hard way was the only way to do anything and there was no path forward except to Git Gud. If you have specific design parameters in mind I find that building screws manually provides much more flexibility. That, and not having your file explode in your face if you happen to open it on a machine that doesn’t have your full selection of plugins installed is always nice.
My solution was actually to change the print orientation and cut a little into the screw. Print reliability and consistency is high and the fit is perfect.
Once I’m done I can probably share the designs
A custom vee thread screw and nut, as you have done, is easily done in the Thread Profile workbench. As a workbench, I don’t think it’s all that popular, at least it’s not going to be as popular as the Fasteners workbench.
Other than creating the head of the screw and the shape of your nut as a separate sketch and pad, you can simply fill a couple of boxes with your own numbers, click the helix button, then click the Additive Loft button, both provided in the workbench toolbar, wait for the threads to generate, and it’s done. And it’s parametric.
I recommend checking it out if you’re using FreeCAD.
If you share the designs it I’ll happily stress test haha… I’m so bad at CAD
Would be interesting to see how it compares to a 3d printed M10 (or equivalent diameter) screw+nut
Thank you!
