MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.

Download Now


Adjustable GT2 Belt Tensioner

by stratop80 Oct 14, 2015
Download All Files

Thing Apps Enabled

Please Login to Comment

At first glance I did like this design more than the version that pushes belt with bolt. But in practice belt is hard to install thight slot and it still is too loose allowing belt to slip when you try to tension it. If this was made from metal or injection mold, this could work much better.

you've saved me! great part! thanks!

Hope you don't mind, I made an even beefier version of this design, all credit to you.


This version is for my CTC printer which needs a little extra strain on the belt to get good prints.

GT2 Belt tensioner- heavy duty- CTC and makerbot
by Raymo99

Of course not! Help yourself, good luck ;-)

When I import the belt_tensioner_clip into S3d, it is over 300mm tall? any suggestions?

seems to be about 25.4x than it should, check import units and procedure. Regards

Great design. I would like to request if you can share the .stl file for a 10mm wide belt if possible. Thanks so much.

HI, thanks! I don't have a 10mm version, though I could give it a try and post. I should have to find some time for that, so it may take a little. Regards!

That would be awesome and much appreciated if you could do that. Regards

You might want to try the new part, I think it should work.

Thanks, I am trying it now, will give you feedback soon!

I had to shim it with cardboard to prevent slipping, but it works nicely.

Very clever design, thank you for sharing it. I'll be printing these later today (when I have access to a printer). I have an open belt that I was going to close with a belt clamp and then tension independently, but it seems to me that I could put the ends of the belt in each end of your clamp, with the gap in the belt being bridged by the screw. Do you think that would work, or do you forsee any problems doing it this way?

Hi, Robanada, thanks for your comment,
I can't see any problem in trying that configuration; in every aspect it is basically the same thing, so, if teeth don't slip as it is now, they shouldn't do this way you're proposing. Good luck!

These are fantastic, the tolerances on the belt teeth and width are spot on perfect. Many thanks!

So glad it suits you, regards!

Thanks for these. My GT2 belt slips through the teeth when I tighten these. Is there anything I can do?

I drew the GT2 profile carefully according to the standard, but its efficiency varies of course on every printed part; Other than that, increasing the normal pressure is the only way to improve grip. Check that the flat side of the belt is not loose, - there are thinner belts than others -, if so you could add a tiny cardboard piece under it to tighten everything up. But if the clip (even printing it a bit smaller, say 95% to tighten the piece) fails at that, you could try with one or two zipties instead of it. Or even a drop or two of cement inside the teeth cavity. Or everything together. Uglier for sure, but, it may work ... ;-) Thanks for your comment!

Don't print those clips standing on their edge... mine are now spaghetti...

Which I'm sure has everything to do with my printer setup, of course. Just a warning to anyone else...

Mmmm, the way the clips are shown in the Thingiview window may be misleading... They should be printed exactly in the other way, with the "J" shape facing the bed, that is, twisted 90º respect to how they're shown there. With enough adherence between layers they should do the trick. Thanks for pointing it and good luck!

I printed them 'flat on their back' with the J prongs facing up like U-shape. That seemed to work. But it occurs to me that leaves a problem with the layers being aligned along the very edge that's going to see stress. As in, I just sheared the hook off one of them because of that. Could be my ham-fisted handling of them too.

It would seem like having the layers running along the length of the pieces would be the strongest, yes?

I tried doing them on their side in a C-shape but that made spaghetti. I'll retry with some different settings. I think I did a raft, I'll try a brim.

I love the design though, don't get me wrong. I'm sure the problems are more on my end than the thing pieces.

I like how well the belt grip teeth turned out. I'm waiting on a delivery of socket head screws, so I haven't had a chance to install this yet.

Just redid them on a better raft, on their sides and they came out great. Now I just need those long screws to show up...

Nah, dont worry, you'll get it sure this time. ;-) I added an image to show what I think its the best way to print it, so that the "fibers" of filament take account of the tension. I think the photo shows too the same configuration if you look it closely. Check settings toimprove adherence and to avoid delamination. Also, being such a tiny piece, you might print more than one at a time, or print other things alongside it, so that each layer has time to cool down a little, before the hotend returns to attack next layer too soon and damage the piece. Thanks, best luck!

Awesome, thanks!

Printed in PLA to tune the belt tension on my Cherry Pi, works like a dream.

will pla be sufficient? (:

I'm not sure, I didn't try. But I think it should do the trick.
Perhaps you might print one and pull at your best :-)) If so, please post :-)
Best regards.

Will it work with an M3x20mm?

A bit too short. It wouldn't leave room enought between the parts for a minimal loop. I think M3x30 is a minimum. Regards!

This thing rocks.

Is there any possibility the belt will come out? I am asking this because Qidi Technology used epoxy everywhere the belt went into a harness because they said people were having issues with it coming out.

Hello, DarkAlchemist, thank you for yor comment,
There must be of course a chance for the belt to come out, but I dont know any case up to now, in a few of them installed that I know locally, nor I've been told by the net.
So it seems that it handles well enough the tensions involved in a common 3D printer, whenever the clip stays in place. Of course, Epoxy or any other glue should improve results,if the need arises for this or other uses.
Best regards!

I suspect Qidi used Epoxy (they even used it on a clip with a lock on the X endstop permanently bonding them together) so people will have to go back to them for spare parts. $$$$$ Just look at their fan that uses a locking clip in mechanism (the new parts cooling blower) that I can't find anywhere else so I would have to go back to them. All of it is to lock you into them.

Probably the best tensioner out there, easy to print, easy to attach and completely adjustable. Works on all Makerbot / CTC / Flashforge models with GT2 belts. Comes in two versions to suit any application.. well done to the designer.

Thank you for your kind comments, Ray. So happy that you find it useful! :-) Regards