Z Adjustment Question

[Brady Watson]

Well done Gary.

-B

[sevans]

I ran into the same issue back in 2007. Made this post: http://www.talkshopbot.com/forum/showthread.php?2605

EXCELLENT! Thank You

[sevans]

Take a deep breath...from experience, it usually something stupid going on. Nothing is unfixable...

Have you called SB to find out how much it is to have a tech come out and get you going again?

-B

The Y Beam (or gantry) is not perpendicular to the table. It is cocked out a bit at the bottom and obviously what is keeping my spindle from being plumb... Is there a fix for this?

[Gary Campbell]

That's fairly common, can you provide picture with a few arrows showing direction of misalignment?

[sevans]

That's fairly common, can you provide picture with a few arrows showing direction of misalignment?

Absolutely!!! See picture. Let me know if you need to see more.

[coryatjohn]

I had this problem when I first set my ShopBot up. The procedure for squaring the Y carriage isn't complicated but it requires a torque wrench and an appropriate hex socket. I'm attaching a document ShopBot sent me to do this procedure.

To determine what is out of square, take a piece of solid wire that fits in a collet (1/8" is about 8 gauge) about 2' long and bend it into a Z so that there's a really long leg of about 18" and a short leg that fits into the collet and another that is a pointer straight down. Mount it in your collet and then turn the collet by hand. Aim the "Z" along the X axis and measure the distance between the pointer and the table. I used a block of wood. Rotate the collet 180 degrees and measure again. If the distance isn't the same, you have an out of plumb situation. Adjust the Y carriage until the distance from the pointer to the table is exactly the same in both directions.

Using this method exaggerates the error substantially. It's like using a 3' diameter bit. If you can get it close with this method, it will be absolutely undetectable using a normal bit. A square works well too but you can't get that fine of a measurement.

One additional bit I got from ShopBot support:

Assuming that the amount the beam is out of plumb is equal in amount and opposite in direction when you check on opposing sides of the Y beam, it sounds like that beam needs to be slightly loosened, rotated by the amount and direction it is out, and retightened. First you will clamp the Y car in a way that will prevent it from moving along the X axis. You will be loosening the bolts on the end plates that attach the end plate to the beam, and possibly the bolts on the gussets under the beam. You want to loosen them just enough that when you gently tap on the spindle the beam is nudged to square. This is best done when the spindle is in the center of its travel. After you have it all plumb, retighten everything to 60 ft/lbs.

[sevans]

PERFECT!!!! Thank You so much

[Brady Watson]

You'll need 2 blocks of wood - 1 per side that sit on top of the gantry. Position the gantry over one of the 3x5 crossmembers before you begin. You'll need pipe clamps long enough to clamp the gantry down to the rails (clamp wood on top of beam to bottom of 3x5 x-member)- in case this isn't obvious in the PDF John posted. It doesn't need to be king kong tight on those clamps...you will most likely loosen the cap screws on the plates and hear/feel it drop into square.

Dont forget to loosen the gussets underneath...and check they don't splay out under the pressure of the clamps. Think of this operation as 'truing up' - it won't take much to get it right.

-B

[sevans]

bend it into a Z so that there's a really long leg of about 18" and a short leg that fits into the collet and another that is a pointer straight down.

I cant envision what you mean by bending it into a Z... You mean like this:

[sevans]

Got it. Consider it done.