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Simple clothespin belt tensioner

by mrice Apr 13, 2014
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This is really a brilliant idea especially for the y-belt. Since it becomes it has more tension when it nears either outer ends and less when in the middle. My friend used it and it really worked like a charm for him

Hey mrice! I love that you’re sharing the clothespin tensioner to those who don’t know about them currently. But I have a few concerns about these tensioners, despite their cost.

I know they work for many people, but in some cases the tensioner, instead of keeping the belt tensioned, flexes due to the strain from the motor instead of moving the belt. This action isn’t very noticeable to the naked eye as the clip only flexes a very small amount in these cases, but even a small amount of flex can cause a printer to seem to have Z ribbing issues.

I liked these clip tensioners and all, but, when I first got my MP select mini, and even My Robo R1, they both had these clips, and they both suffered from the same issue: Z axis ribbing. When I got rid of these clips I printed out the Ultimaker belt tensioner, and It greatly reduced the amount of ribbing.

But, to be fair, if you really want to still use these instead of some other fixed tensioner, there are a few ways to diagnose the Z ribbing issue you may get from these.
Slow down the print. Try to slow it little by little until Ribbing is reduced by a noticeable amount.
Try to avoid XY axis jerk. Jerk will CERTAINLY increase ribbing with these clips, Try to reduce it in your printer’s EEPROM settings.
*Reduce accelerations. Doing this will increase print quality whether you have this clip or not. But you can still try.
If all else fails, just try the other clip. Trust me, it works like a dream on my printers, and I can print 120+ on both of them now.
So, in the end; I, and even Thomas Sanladerer himself said that these clips aren’t good to use, a,d I would strongly advise against them, but that’s only a recommendation.

Sorry I had to be on such a low note about this thing, and I’m not trying to tear on you, mrice, but I just want to spread the word about them.

Good Day!


Ultimaker Belt Tensioner
by Gijs

I love this! It's so simple and effective! I spent a long time staring at the various other ideas and in the end, better is the enemy of the good enough. I put this on my Prusa i3 - Y axis table and it tightened right up. The wavy lines on my parts have gone way down. The whole thing tucks up under the table anyway, on the opposite side of the belt, so nobody sees it anyway. Many thanks!

Thanks man, works perfectly!

Use them the other way round!

The wire ends in the smooth side of the belt and the coiled section over the belts teeth ...

That way works better

Many thanks. Ive been printing different sized belt tensioners for a while, now I just bend this one for adjustments

Running great on my Y axis. X was already re-tensioned or I would have done it on that one too. Great post and idea, thanks.

Great idea! I got a pack of 50 for just under $3, still a bargain. I just slipped the spring off one of the pins and bent it open. Since I'm using the wider XL belts on my repstrap I didn't bend the ends into U hooks, just slipped the spring onto the belt. It adds just enough tension to keep the belt from sagging and flapping. Don't want to tension the belt TOO much, I destroyed a motor that way by bending the shaft!

Cool, but i have my doubts about it not flying of and lodging itself in your eye. :)

so... How is it working after testing for while?

Holding up like a champ.

Whatah a good idea my friend! Thanks very much!