I have my bender set up and it seem that the top and bottom horizontal pieces tend to twist ever so slightly when bending throwing my die out of level. The bolts are super tight. I have taken it off the stand and built a small cart using the same 2 bolt system and its the obviously the same. I was thinking of welding the the upper arm and lower are together on each side so they can't shift. Has anyone had any experience with this?

Pic for reference


Thanks,
David