Shopbot owners in Chicagoland area for tech help?

[MaxFrenzy]

I'm wondering if there are any shopbot owners in the Chicagoland area that are handy on the machine side. I'm located near O'hare. I have a 2002 Benchtop PRT, and am finding that the rails that the Y car rides on are not parallel. As a result, I'm having a hard time getting the v-rollers to ride where they should and getting everything else squared up appropriately. I'm going to continue to try to do what I can, but if there is someone more experienced, that would be great. I wish I could teleport Brady to my shop.

Thanks
Matt

[bleeth]

I bet you can fix it yourself. The Y rails are bolted to the ends and you have adjustment room from oversize holes when you loosen them up. You want two things: Make sure the first rail you adjust is dead perpendicular to the x rail/end plates. Then adjust the second rail to be parallel to the first. With the distance between v-grooves on the rollers as a give, cut a pair of spacers from some wood stock that are the right length and firmly, but not to tight, clamp it up and then tighten.
You may need to remove the z-car, or at least loosen the lower rollers. Typically getting the y rails just right is done before dropping the z car on it. You also then want to make very sure the z car rails that ride on the y gantry are parallel, but they can be almost self aligning if you are gentle about loosening and then setting them. When you have gantry rails perpendicular to x and in parallel, this is the time to gently freewheel the gantry up and down the x (with motors unplugged-very important) and make any adjustments to the concentric rollers so all 4 rollers ride smoothly and constantly on the rails. After you set the car, you want to do the same thing with it before you tighten the bottom holing rollers.

Getting your tool really square and parallel where it should be is a bit touchy but well worth it. Back in the day when the PRT's were being produced there was a lot of discussion about stiffening them up and keeping them square. Added gussets from the rails to the end plates was one thing used and some actually spot-welded them after they were very sure they were square.

[MaxFrenzy]

I bet you can fix it yourself. The Y rails are bolted to the ends and you have adjustment room from oversize holes when you loosen them up. You want two things: Make sure the first rail you adjust is dead perpendicular to the x rail/end plates. Then adjust the second rail to be parallel to the first. With the distance between v-grooves on the rollers as a give, cut a pair of spacers from some wood stock that are the right length and firmly, but not to tight, clamp it up and then tighten.
You may need to remove the z-car, or at least loosen the lower rollers. Typically getting the y rails just right is done before dropping the z car on it. You also then want to make very sure the z car rails that ride on the y gantry are parallel, but they can be almost self aligning if you are gentle about loosening and then setting them. When you have gantry rails perpendicular to x and in parallel, this is the time to gently freewheel the gantry up and down the x (with motors unplugged-very important) and make any adjustments to the concentric rollers so all 4 rollers ride smoothly and constantly on the rails. After you set the car, you want to do the same thing with it before you tighten the bottom holing rollers.

Getting your tool really square and parallel where it should be is a bit touchy but well worth it. Back in the day when the PRT's were being produced there was a lot of discussion about stiffening them up and keeping them square. Added gussets from the rails to the end plates was one thing used and some actually spot-welded them after they were very sure they were square.

On the benchtop PRT, the x and Y rails are reversed relative to the shopbot buddy design. Thus, the x axis is the fixed 32" rail and the Y is the 24" moving deck. There is a Y car attached with 8 v-rollers (4 horizontal, 4 vertical) that ride on the "sharpened" L shape angle rails. The rails are not parallel and at this point, I'm not sure if either is actually square to the x rails. Theoretically, if one was already square, I could simply adjust the other. I'm not sure if what the right process is to go about fixing it, for example, taking off the Y car first, then adjusting the rails, then sliding the Y car back on and adjusting from there or if I can try to do it with the Y car still on rails. That's why I'm kind of looking for someone who has done this process before or at least something similar with a PRT so I could have a 2nd set of eyes and another brain to help out. Reading from your post, thing don't quite make sense because the z car isn't connected here...I'm assuming that's because of the reversed setup relative to the buddy design mentioned before. However, getting one rail perpendicular to X first seems to be the right method to take.

Thanks

[bleeth]

I was speaking of a PRT and not a Buddy, although the benchtop does have a bit of difference from the "big boy" When getting a new full size (or 4 x 4) PRT from SB the first step once you had your frame built or assembled was always getting one x rail straight and level, then the other, then moving on to the Y's and finally the Z. Whether you bought it new years ago (and I know that is not the case here) or got it used recently, aligning the axes properly is more patience and working out a couple jigs to help than technical knowledge. Personally, I believe working it out is a great way to get to know your tool. Unlike the high end big iron tools, SB's are intended for user assembly, adjustment, and repair. For your benchtop I would remove the z car before I tried to get the x rails right. Then move on to the Y carriage. If it seems too much for you then I do hope that someone in your area responds. Not too long after I got mine I had a catastrophic gantry crash and it totally freaked me out. I posted and a local botter responded, came over, and helped me get it properly reassembled and adjusted. I think I could have worked it out on my own but his help sure made it easier. I'm just trying to shoot some thoughts your way until or instead of local help arriving.

[MaxFrenzy]

I was speaking of a PRT and not a Buddy, although the benchtop does have a bit of difference from the "big boy" When getting a new full size (or 4 x 4) PRT from SB the first step once you had your frame built or assembled was always getting one x rail straight and level, then the other, then moving on to the Y's and finally the Z. Whether you bought it new years ago (and I know that is not the case here) or got it used recently, aligning the axes properly is more patience and working out a couple jigs to help than technical knowledge. Personally, I believe working it out is a great way to get to know your tool. Unlike the high end big iron tools, SB's are intended for user assembly, adjustment, and repair. For your benchtop I would remove the z car before I tried to get the x rails right. Then move on to the Y carriage. If it seems too much for you then I do hope that someone in your area responds. Not too long after I got mine I had a catastrophic gantry crash and it totally freaked me out. I posted and a local botter responded, came over, and helped me get it properly reassembled and adjusted. I think I could have worked it out on my own but his help sure made it easier. I'm just trying to shoot some thoughts your way until or instead of local help arriving.

The router slides back and forth along the x rails exclusively. The independent Y deck (moving back and forth) is what I am trying to get both parallel and square to the x axis. After they are correctly positioned perpendicular, logic would tell me that simply making sure my z assembly is parallel with the X rails should ensure that it is also square to the Y axis via transference so to speak. At the moment I'm considering order of operations here. It would seem that I would need to remove the Y car off the rails that the v-rollers track along by removing an end-stop and sliding the car off. At that point, make my adjustments to the rails then line up the vertical v-rollers...and then position and finally snug in the horizontal v-rollers taking advantage of the eccentric nature. I'm going to give SB a call tomorrow to see what their thoughts are. I may need to post some of these questions in a different section of the forum..I'm not too sure how many people frequent this sub section. I do appreciate your attempts to help though.

Thanks

So that router slides