Misalignment of y- axis

Have my long mill for 6 months now and it`s been working pretty good until today…While traveling the along the y-axis for some reason it stopped or bound up on the right side…The left side kept traveling until I hit estop… The mill is square and everything is tight…Any ideas what the trouble is?

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Fireman, check your backlash nuts, my guess is they are not adj correctly. If you can turn your lead screws easily the backlash nuts need adjusting. Run the Y axis all the way forward until both sides contact the front, let it chatter for a second then back it off. Tighten the backlash nuts just to the point where it’s hard to turn the lead screws by hand and you should be good to go.
Hope that helps, good luck. Let us know if that helped.

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I think it is worth checking for squareness as part of the regular maintenance routine. It may appear mysterious when things suddenly stop working, where they had previously worked, but CNC machines are subject to mechanical vibration which can loosen bolts that were previously tight. I use a weekly check routine that includes making sure all of the bolts and screws are tight. I use a small torque wrench to tighten everything to the same degree (5 Nm). It takes a small amount of time. Anything that has worked loose in a week gets fixed with a small amount of blue thread locking compound.

Squareness is really vital and an accurate check is necessary. I use a calibrated engineering square with a solid base and a 7 inch long blade. I found my machine was not square after a few months of use. Hobby CNC machines are somewhat fault tolerant because they are not generally being asked (or expected) to mill a workpiece to ± a few 10ths of thousandths of an inch. At some point they slip outside of the parameters you want them to work within and you see binding of carriages and X rails and inaccurate measurements on milled parts. A regular routine for maintenance… with values that can be reproduced, will go a long way to eliminating the variables that can bring a machine to its knees. Do follow the excellent suggestions from @MikeH.

EDIT: spelling and grammar

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Hey Mike…I thought I had the backlash nuts tight enough but apparently not because I tightened them a bit more and all seems to be working fine now…Thanks so much.


@Fireman1963 I’m glad that Mike’s advice solved your problem.

As your problem is resolved, I’m closing this thread. Anyone with a similar issue is invited to start a new thread setting out their particulars.