problem w/gantry wheel on PRS 96x48

[Bernie]

I have one wheel that stops turning for about 16-18" midway down the rail - the other wheel on that rail turns freely during the entire traverse - is this indicative of a dip in the rail or a problem with the positioning of the wheel ?

[Brady Watson]

If it is along the X axis, then first - make absolutely sure that the machine is dead level. If not, the rails will be twisted and a wheel will come up. Level the 4 outer legs first, then drop center legs to the ground and then tighten 1/2 to 3/4 of a turn to put the weight on it.

It is possible that one of the gantry end plates is slightly out of whack as well. If this is the case, you need 2 wood blocks and some long pipe clamps. HOWEVER...before you do this, you should have a large framing square that you can use to find out which side needs to be adjusted. If you adjust the wrong side, your spindle will be pitched down one way or another - so investigate what you need before proceeding.

You'll put the blocks on the gantry extrusion to protect the upper rail. Then clamp BOTH sides of the gantry down to one of the 3x5" steel crossmembers. Then loosen up the 10mm hex bolts on the end plate where the wheel is sitting up AND the 1/4" hex bolts (8 of them) on the gusset underneath. You are only loosening the 'off' side.

Once you loosen up, you should see/feel the wheel fall back into place. Tighten everything up and all 4 wheels should now be sitting correctly. Run it down the rails and check your work.

-B

[Bernie]

Brady - Thanks for the suggestions - We (mostly senior member Steve G) finally got it tracking quite nicely - did the rail/wheel alignment, cleaned out a bunch of sawdust that was packed into and under the rails - loosened the endplate and gusset - wheel went into place - retightened everything - now the wheel is turning full length of the traverse -

I appreciate the help!!

Bernie