Trouble Squaring Y axis

I’m having difficulty squaring the Y axis per the instructions in the video. I’m out of square .011 as measured on a 2-4-6 block. I’m able to rotate the ball screes a little bit but then I encounter resistance. Once I hit this resistance if I continue to turn the ball screw it snaps back to the original position when I release it. The cable to the motor attached to the ball screw has been detached from the control unit and all the proper bolts holding the X gantry are loose per the instructions. Any ideas what to do? Eat more Wheaties?

Loosen all the bolts about 1/8 turn that secure the gantry and see if that offers the necessary compliance for squaring.

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My ball screws seemed to have tight and loose spots, i just used a vice grip with a cut rubber hose to hold the ball screw in place while i measured again.

Thanks for your help. I took both of the actions suggested and got the out of square to .001 over 5.5 inches. I tried to get to less than .0005 but after 15 hours of total time squaqreing the gantry I decided that I would have to live with it. I know pure machinist would not accept that much deviation , but I am only a hobbyist.


did it help loosening all the gantry screws or was it still tight? Most 246 and 123 blocks are only square to like .0003 per inch so within .0015 is within the accuracy of a standard cheap block. Nice stuff is .0001 an inch and then if you can get a nice ceramic square you can improve on that.

I ended up having to loosen the three screws on each side as described in the video along with three bolts on each side that connect the gantry to the carriage that rides on the bearing blocks. I was able to get most of the deviation out with these bolts loose but still needed to use the vice grips with a rubber hose to hold the ball screw in position to tighten all the bolts. With the vise grips in position I was able to get to .0002 deviation but one I tightened the bolts and reinstalled the motor cable, turned the machine back on and then remove the vise grips the deviation was .001. I started over several times, each time getting to .0002 but one the bolts tightened I was still at .001, so I accepted the error and moved on. Thanks again for recommending using the vice grips to hold the ball screww in postion.

Yeah certainly I had to fuss with it a few times as well I ended up over shooting it and it came back a little. Waiting to buy a high quality setup block to redo. the limit switch adjustment was more annoying for me, I have parts on order for a super fine thread adjustment. seemed impossible to tighten lock nut without screwing up the setup.

Just an FYI…you need .012" deviation between switches triggering to induce a .001" deviation in the X axis. Get it close, but it doesn’t need to be perfect.

I had a similar issue and approached it slightly different. I got the y/x relation perfect by using a 1/2 wrench and finally adjusted the ball screw lock nut to get it perfect while at the same time traversing in X on a 246 that was perfectly squared to Y. I then set my limits and tightened everything down and rehomed which brought it back out of square. I lock tighten the threaded rod into the carriages and adjusted the Y2 threaded rod in and out and rehomed a few times so the switches would cause the gantry to align back to perfect. Is the only way I could get the switches to home perfect and autosquare. I think there’s just too much playin the switch activation by just hearing the clicks or using a meter. It seemed to work well. got the sqaure back in within a tenth