Backlash

Hi . I'm setting up a new to me PRS which is replacing my old unistrut machine that has served me well for 17 years . I must say that I am impressed with the evolution of the shopbot . I am having a bit of trouble though figuring out how to tension the pinions against the gear racks on the X axis . ---How much backlash is acceptable ? --On the old unistrut machine I think the frame flexed enough to allow me to set things up pretty tight

Mike,
You'll see the racks are adhered with automotive trim 2 sided adhesive tape. I found this a bit strange at first, but the roughly 1/16" thick center is a sponge rubber composition which essentially acts as a very slight cushion, though not certain if that was the idea when selecting this method of attachment. While others may find it a bit over the top, after 5 years use and maintenance, I've developed a habit of using a "Quick Grip" squeeze trigger clamp torqued quite firmly to hold those motors up as I tighten them and their gears snug to the rack.

Hope that helps, and hope others chime in with more technical prowess to confirm or correct my methodology.

Jeff

I was told just to push up hard.
It has worked well for us.