M5 T-slot nut substitute

by csweichel, published

M5 T-slot nut substitute by csweichel Aug 18, 2012


Off-the-shelf T-slot nuts are incredibly expensive. So many have set out to replace those with printed parts, always replicating how those nuts work thus putting a lot of pressure on the printed nut.
With this thing, all load of the joint is put on a 1mm washer, held in place together with the M5 half-nut.
This substitute prints without support and should be sliced at 0.2mm layer-height. If sliced at a different height, chances are it won't fit.

This part served as a T-Slot nut substitute for my MendelMax build, using uk.rs-online.com/web/p/products/837-234/ nuts and uk.rs-online.com/web/p/products/525-931/ washers together with KJN extrusions.

The OpenSCAD file contains part of Catarina Motas Shape Library: svn.makerbot.com/users/hoeken/openscad/shapes.scad

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you would be incorrect.. after printing them the nut is press fit with the washer on top and a tight fit in the extrusion. once the screw/bolt is even slightly tight the plastic is no longer an issue and it tightness right up. wouldn't recommend a lot of disassambly/rebuild of them but for a set it and forget it. They work like a charm

cool, very good to know. Thanks for sharing!


The nuts are holding just fine. I tightened them all again after about two weeks and they've been working fine ever since

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1) print many of them
2) insert nuts and washers
3) be happy that you saved a lot of money


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jebba on Dec 20, 2012 said:

If you derived this from two GPL projects, how can you make the derivative NC?

csweichel on Dec 20, 2012 said:

In this case the derivation is more like inspiration rather than actual asset reuse. This thing is developed from scratch and the items I "derived" it from were more like the starting points that made me design it in the first place.
Thus I'm not bound by the GPL in this case and get to choose the licence.

111OCT111 on Nov 29, 2012 said:

Hey Blacki, 
I´m curious to know if your printer is holding up with your printed t-nuts.
Did you use it intensely enough to test the durability?

csweichel on Dec 20, 2012 said:


The nuts are holding just fine. I tightened them all again after about two weeks and they've been working fine ever since

thecrazy on Oct 19, 2012 said:

Forget what these chaps bellow are saying (except wilot309) this is a very good design. The only force applied to the plastic part is rotational. It acts like a wrench holding the nut in place when tightening the screw, after that all it does is keeps the nut and washer centered in the channel so they cant move and pop out.

This is probably the ONLY printed t-nut that is as solid as the real thing.

wilot309 on Aug 21, 2012 said:

Very nice, I like how this is simplified from the ones it is derived from, I did not see the point in the extra plastic that was in the groove of the T-slot nad now you are able to add a washer.

I am confused by why people think this will not work, or would not be as strong, possible not quite as strong, but the essence of this part is to merely hold the nut and washer in place until they are tightened up, once tightened up, in theory the plastic servers no purpose?

csweichel on Aug 21, 2012 said:

that is correct, the plastic only holds the nut and washer in place. Once tightened, the plastic part is only needed then the nut is to be loosened again.

This thing just makes the nut/washer combination more convenient to use (or usable at all).

JamesNewton on Aug 19, 2012 said:

Won't be as strong as a real metal t-nut, but may do just fine for many uses. I've always just purchased carriage bolts and then ground off two opposite sides of the flange on the bolt. That makes a t-bolt instead of a t-nut, but most of the time you can use that instead. On the rare cases where a t-nut is really required, I've used a thick washer with the edges ground off in combination with a nut. They can be epoxied together to keep them from falling apart when you insert them. This design is great for light use.

thantik on Aug 19, 2012 said:

I don't get it. Aren't these pretty much useless? Your design doesn't actually trap the nut, so once you tighten the nut, it just slips through the printed T-slot piece. You'd be better off not printing anything and just using the washer.

JamesNewton on Aug 19, 2012 said:

thantik, it goes the other way round. They are upside down in the picture. Imagine the bolt coming up through the table, thru the printed part and /ending/ at the metal nut.