Belt tension X Y

I notice a difference of belt tensions between the X belts (670 mm) and the Y belts (685 mm).

The X belts are less tightened than the Y belts, even if the clamps are tightened in the same way, and although it does not affect the printing ( i thing and i hope).

I don’t understand why because i have only the clamp to tighten the belts, and the Y belts are not too much tightened.

I replaced one X belt with a new one and it is worse !!!..

Does anyone has encountered this problem?

Thanks for your replys

It doesn’t matter much as too much tension in the X-Y belts is not suitable.


Same problem here,
very big difference between X and Y belt tensions…
So, is not possible to print 0.1 mm resolutions.

I added two bearings on two M6x50 mm bolds (in extra holes) in the front and rear panels.
Hope it will work !!!

Greetings from pajottenland,

Hi Marc

I don’t understand how your two bearings are mounted and how they are working on the belts. could you explain more?

i have a doubt on the distance between the translator bars, according with a “standard” belt dimension…

To minimize this problem a have added a little piece of toothpick at the summit of the triangle of the belt clamps, to press on the belt only on the tooth pick and summit of triangle.

In fact, as the clamp has an horizontal portion, on each side of the triangle, when you tighten the clamp with the two screws, the belt is tighten at the beginning of screwing. After a limit, due of the horizontal part, the belt is stretched inside the clamp, and screwing more has no effect on the belt tension.


Hi jodela,

Here some pictures, how I adjusted the belt tensions.

  • First I drilled 6mm holes left and right side of the front panel:

  • Then I drilled only one 6mm hole in the back panel:

  • You can’t drill on the left back, there is the end loop switch:

  • What you need is all this (in M6):
  • the bolts are M6x50mm
  • the bearings are d=6 / D=19 / Width=6 mm, so you have total 12mm width.

  • Assembled it looks like this:

  • And installed in the front panel it looks like this:

  • And in the back panel:

You need two bearings on each axis, one is to small, the belt is moving (left <-> right) inside the pulleys.

Greetings from pajottenland - belgium

Hi Marc,

Thank you for your nice photos and explanations.


Looks nice Marc.
But I wouldn’t use a countersunk screw, I would add another washer on the outside so you don’t create diagonal forces on the drill hole but rather “clamp” the plexi and spread the force on the entire contact surface of the washers. Because this looks like it can start crack the plexi any minute. (my 2 cents by looking at the pics I could be entirely wrong though)

Kind regards.