Gantry is not square

Just got a new to me K40. It needs a new tube and some TLC, but I think I still got a deal at $40.

The gantry is a bit out of whack though. How can I square this up?

Welcome to the forum. :slightly_smiling_face:

One easy way to try and correct that out of squareness is to adjust the right side of the x rail down some. To do that you will need to loosen the right side belt.

The tensioners for the belts are on the backend of the rail on each side. To access them there are small holes on the back of the machine in line with the screws of the tensioners. You will need a long screw driver to reach them.

So loosen the right side belt and try and pull that side down some. You may not be able to get all the way square.

It’s also possible the the x-rail on the left side is not cut square on the end. You might be able to shim it some if that is the case.


Actually here is a similar post I answered with pictures.


There is a coupler/spider in the front right. If you loosen it, you can move the left and right sides of the gantry independently.

You can remove the black L profile cover thingy in the front to make that easier. There is no real need to put it back. It’s mostly cosmetic. Just make sure that the head can’t reach the motor.


The rail was not cut square. I cleaned up both ends and it’s good now. Thank you!