Z Adjustment Question

[sevans]

Does anybody out there know how to adjust these? Everything I've found in manual and online is very vague. Many Thanks for reading!
:D

[Joe Porter]

https://www.smslinear.com/pdfs/GuideWheelsWeb.pdf This may be of some help.. One side has non-adjustable bushings and the other has the adjustable. You would probably need to unload the Z carriage and disengage the motor and try to come to a smooth even motion when moved by hand and no slop.......hope is of some help...joe

[Brady Watson]

It isn't a fast ordeal - esp if it is your first time doing it.

Observe that there are eccentric/cam bushings on the one side & stationary ones on the other side. You're going to leave the entire (left side in pic) alone and focus on the right side. You'll need a 1/4 & 1/2" box wrench (if my memory serves me)

Start by loosening the Z motor plate on the back of the YZ car using a 3/16" allen key (Horrible Freight hex sockets are great for this) - disengage the pinion from the rack.

Make yourself a looped piece of wire to hook one of the springs, release it from its perch and let it hang there. Leave the other one on. Then run the entire stroke of the Z up and down by hand.

Adjust the v-rollers via the adjusting cams by first loosening the axle bolt (going through the bearing) - a LITTLE...then adjust the cam to create tension against the rail. MAKE NO LARGE ADJUSTMENTS - this is fine tuning...so even small adjustments to clock position will make a big difference. You want to make absolutely sure to stroke the Z up and down while or right after adjustment to make sure it runs smoothly & that it isn't adjusted against the rails too hard.

It's going to be 'about right' when you tension the roller against the rail and you can no longer rotate the v-roller by hand without the Z moving up or down.

After adjusting, tighten up the through bolt and check it again - work the Z all the way up and all the way down. How does it feel? Wiggle it all over - feel how much resistance there is as you roll it. Do you feel that is 'right' ? Will the motor struggle to get the Z moving? You should be thinking all these things and adjusting for them - and also making sure it isn't too loose (duh).

Then pull the spring back up to its perch, engage the Z motor/pinion in the rack and make sure it isn't loose (backalsh) afterwards by turning on the control box and wiggling the Z up and down. Adjust as needed.

Take your time - you'll be fine.

-B

[sevans]

It isn't a fast ordeal - esp if it is your first time doing it.

Observe that there are eccentric/cam bushings on the one side & stationary ones on the other side. You're going to leave the entire (left side in pic) alone and focus on the right side. You'll need a 1/4 & 1/2" box wrench (if my memory serves me)

Start by loosening the Z motor plate on the back of the YZ car using a 3/16" allen key (Horrible Freight hex sockets are great for this) - disengage the pinion from the rack.

Make yourself a looped piece of wire to hook one of the springs, release it from its perch and let it hang there. Leave the other one on. Then run the entire stroke of the Z up and down by hand.

Adjust the v-rollers via the adjusting cams by first loosening the axle bolt (going through the bearing) - a LITTLE...then adjust the cam to create tension against the rail. MAKE NO LARGE ADJUSTMENTS - this is fine tuning...so even small adjustments to clock position will make a big difference. You want to make absolutely sure to stroke the Z up and down while or right after adjustment to make sure it runs smoothly & that it isn't adjusted against the rails too hard.

It's going to be 'about right' when you tension the roller against the rail and you can no longer rotate the v-roller by hand without the Z moving up or down.

After adjusting, tighten up the through bolt and check it again - work the Z all the way up and all the way down. How does it feel? Wiggle it all over - feel how much resistance there is as you roll it. Do you feel that is 'right' ? Will the motor struggle to get the Z moving? You should be thinking all these things and adjusting for them - and also making sure it isn't too loose (duh).

Then pull the spring back up to its perch, engage the Z motor/pinion in the rack and make sure it isn't loose (backalsh) afterwards by turning on the control box and wiggling the Z up and down. Adjust as needed.

Take your time - you'll be fine.

-B

i just can't even thank you enough for this information. I have been working at it for quite some time now and am getting so frustrated. It pains me that no matter what the left rollers will never align with the wheels. Is there any modification you might recommend to remedy this? Should I have the spindle mounted when making these adjustments. Again. I'm so excited to have these replies. Feel much better now.

[Brady Watson]

Yes - leave the spindle on there - but there's no problem taking it off. No problem taking off both springs either. It's totally up to you.

In terms of "no matter what the left rollers will never align with the wheels" I need some clarity. Please post a pic or two showing the issue you speak up and explain the problem.

Keep in mind they only used this exact setup for a year or two until SB realized just how much of a cluster it really was...this is not to say it won't be OK, just that there isn't much in terms of documentation - as you've already discovered.

Now just going off of memory here....there is a possibility that the aluminum block(s) that hold the rollers on, somehow walked over . What I mean by that is the AL blocks are bolted to the big plate on the back side. It is possible that the bolts have loosened or walked outboard so that no matter how much you adjust the cams/eccentrics, there isn't enough adjustment.

If you determine that's the case, you'll have to remove the 2 bottom v-rollers from the big plate & lift the entire assembly off the gantry. You may find first removing the spindle & z motor - and just let them lay on the table (and Z motor on top of gantry beam) - and the Zzero plate and Y proximity switch wiring - drape them off to the side (and the Y motor - just watch straining the wires - don't let it dangle). You'll only need some zip ties to get them back on so no big deal.

After the whole deal is off - it will be a lot easier to track down and fix the problem. Don't over-think things - this is strictly a mechanical issue. The fact that it's attached to a robotic tool means nothing...it's easier than working on a riding mower shift linkage or something like that - so dive in. Take pics and video as you disassemble if you're not sure, but....I don't think you need to.

Post back to let me know how you make out.

-B

[sevans]

I definitely will send a pic when i get back to my shop. Shopbot told me that they would never line up just right. The blocks are securely in place. It appears that something would have to get shimmed if those wheels were going to line up... Thanks so much for your support. It means a ton!!!!@

[sevans]

In terms of "no matter what the left rollers will never align with the wheels" I need some clarity. Please post a pic or two showing the issue you speak up and explain the problem.



HAHAHAHA...did I say that? I apologize...For some reason I keep calling the Z the X and so forth and so on. Not great for getting support. What I meant is that the V Rollers will never align with the Rails of the Extrusion. It does not appear to be physically possible. ....

[sevans]

You know what...I don't know what the problem is. I have lost sight of it at this point. I started down the "Mechanical Issue" road 2 weeks ago and still nothing. I have removed and replaced the entire ZY carriage twice now. Nothing changes. I have created problems searching for answers. Still now I am faced with getting it all back together. Sorry keep posting...but just needed to let that out. -SE

[Brady Watson]

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

[Gary Campbell]

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

[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. :Dhttp://www.talkshopbot.com/forum/attachment.php?attachmentid=31353&stc=1

[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:

http://www.talkshopbot.com/forum/attachment.php?attachmentid=31355&stc=1

[sevans]

Got it. Consider it done. :)

[Red F]

I'm pretty sure that is what he meant by bending it into a "z"

[coryatjohn]

Yup. Exacto. Essentially, a 3' diameter one flute bit.

[Gary Campbell]

Before I used my tram gauge, I used the "Z" rod method, but only 1 foot long. Even tho the longer length will exaggerate the error, the flex in the rod was a detriment. The best way is to use a tram gauge, but the cost of those gauges added to a surface plate is more than the occasional user wants to bear.

http://www.talkshopbot.com/forum/attachment.php?attachmentid=31356&stc=1

[sevans]

Before I used my tram gauge, I used the "Z" rod method, but only 1 foot long. Even tho the longer length will exaggerate the error, the flex in the rod was a detriment. The best way is to use a tram gauge, but the cost of those gauges added to a surface plate is more than the occasional user wants to bear.



Yep. I have a spindle square like that. Always showing out in X Direction.

[sevans]

I just pulled an x motor just to check it out. Took off the pinion (WITH MUCH FORCE). I noticed after that where the set screw hits the shaft of the motor is just mutilated. The key also has so much set screw damage. How do you deal with that? Is it normal when turning the pinion back and forth slightly to hear a click in the motor? Same is so for all of mine it seems. Just wanting to rule out motor failure.....

[sevans]

Just for the record......... this is the problem I'm having. Been cutting signs like this for years.... Super smooth. Now this and seems to be getting worse.
http://www.talkshopbot.com/forum/attachment.php?attachmentid=31357&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=31358&stc=1http://www.talkshopbot.com/forum/attachment.php?attachmentid=31359&stc=1

[curtiss]

Can't seem to locate the post,

but a few years back someone added some adjustable setscrew brackets on their Z axis which made it very easy to micro adjust...
sort of like leveling a pool table.

They would then simply lock the setscrews in place with a nyloc nut.

[Joe Porter]

The click you hear and can feel is due to backlash in the motor gearbox. This the Oriental Tapered Hobb motor which ShopBot and others say can be adjusted, I have tried and can't seem to find the sweet spot between zero lash and loading up the gears. This is from Oriental's website, this should give you an idea of what is going on. http://www.orientalmotor.com/stepper-motors/technology/stepper-motor-gearheads.html as far as the scarring on the pinion shaft, I would just clean it up a little with a fine file (I didn't say to make a flat spot) just remove metal that may be raised on the shaft. If the key is damaged, do the same or get a new key. I hope this is of some help...joe

[sevans]

The click you hear and can feel is due to backlash in the motor gearbox. This the Oriental Tapered Hobb motor which ShopBot and others say can be adjusted, I have tried and can't seem to find the sweet spot between zero lash and loading up the gears. This is from Oriental's website, this should give you an idea of what is going on. http://www.orientalmotor.com/stepper-motors/technology/stepper-motor-gearheads.html as far as the scarring on the pinion shaft, I would just clean it up a little with a fine file (I didn't say to make a flat spot) just remove metal that may be raised on the shaft. If the key is damaged, do the same or get a new key. I hope this is of some help...joe

Thank You for the info. Today I realized, and not 100% sure how I feel or anyone else will, that the pinion set I received is slightly bigger than the original. I practically have to hammer on the originals....these slide on with no problem. The set screws are in a different place...this is how I saw the difference. I pulled out my old set and cannot even test them out because they are so tight. There are protruded burr areas on the motor shafts where the set screws have damaged them. I don't know if it's normal for pinions to vary in size like this, but it's evident that the force of the machine is primarily on the set screws. In addition there are damaged areas inside the pinions from the shaft slipping I guess. Just thought I'd share. I'm hoping that my motors don't need replacing.

[Joe Porter]

I have a 2008 Buddy with the red label motors that look like yours. I ordered one new pinion gear and talked to ShopBot directly to make sure the order was correct. The pinion they sent me was for .5" shaft dia. It turns out my motor had 12mm dia. shafts which is about a .028" smaller. I had no idea there was a difference. I thought they would know, but the new pinion was too big for my motor. You may have the wrong pinions for your motors. If you can get a digital caliper that can measure MM, check the shaft size and see if you have the right pinion gears. You mention having to use so much force to remove the old pinions, I was able to remove and replace this one pinion with only hand or maybe gentle pry bar force, nothing dramatic. Other people have had similar problems as you. I wonder if the correct pinions were matched to the correct motor shafts from day one? Hope this is of some help...joe

[sevans]

I have a 2008 Buddy with the red label motors that look like yours. I ordered one new pinion gear and talked to ShopBot directly to make sure the order was correct. The pinion they sent me was for .5" shaft dia. It turns out my motor had 12mm dia. shafts which is about a .028" smaller. I had no idea there was a difference. I thought they would know, but the new pinion was too big for my motor. You may have the wrong pinions for your motors. If you can get a digital caliper that can measure MM, check the shaft size and see if you have the right pinion gears. You mention having to use so much force to remove the old pinions, I was able to remove and replace this one pinion with only hand or maybe gentle pry bar force, nothing dramatic. Other people have had similar problems as you. I wonder if the correct pinions were matched to the correct motor shafts from day one? Hope this is of some help...joe

Thanks for letting me know that. The shaft on my motor measures 12mm. The original opinions were a tight fit. The new ones can spin around on the shaft (without key) not so for originals..Browning EN 6418 ....can't find them anywhere

[tomhartnett]

For all the motors sold over the years the pinion shaft sizes have been .5", 12mm or 14mm, just depends on the motor model.
normally to make sure you get the correct pinions we will ask you for the motor model and the rack width. since they are machined bore pinions the fit can be tight on some of them. I'm certain that if it were the wrong size pinion you would not be able to hammer it onto the shaft at all, there's at least a half millimeter difference...but I won't say that it isn't possible. I don't have the motor spec sheet with me so you'd have to shoot support an email to confirm everything is right with your motor model-pinions.
it sounds like you need to replace the keyway and the setscrew as well.
if the shaft itself has too much damage (and the issue is appearing in the X axis) we can do a simple test. if your Y axis or Z axis motor is the same model, swap one of them and their pinion/keyway with the X motor and see if that tightens up the x (and possibly causes a problem in the other axis but will tell you the issue)

With the pinion on or off, motor unmounted and power on, does the click back and forth you hear translate to a discernible amount of play? very small amounts to play are normal even in low-backlash motors and don't often translate to discernible differences in cut quality with most bits/operations with normal stepover.
there was a time where using a dial indicator to measure the amount of play an axis has seemed like a good method to measure and correct overall play, but overwhelmingly using the push-pull method is the most practical. if push pull doesn't find anything then the issue often is elsewhere (like motor/pinion/rack engagement, tool level, YZ car square/plumb)

[sevans]

For all the motors sold over the years the pinion shaft sizes have been .5", 12mm or 14mm, just depends on the motor model.
normally to make sure you get the correct pinions we will ask you for the motor model and the rack width. since they are machined bore pinions the fit can be tight on some of them. I'm certain that if it were the wrong size pinion you would not be able to hammer it onto the shaft at all, there's at least a half millimeter difference...but I won't say that it isn't possible. I don't have the motor spec sheet with me so you'd have to shoot support an email to confirm everything is right with your motor model-pinions.
it sounds like you need to replace the keyway and the setscrew as well.
if the shaft itself has too much damage (and the issue is appearing in the X axis) we can do a simple test. if your Y axis or Z axis motor is the same model, swap one of them and their pinion/keyway with the X motor and see if that tightens up the x (and possibly causes a problem in the other axis but will tell you the issue)

With the pinion on or off, motor unmounted and power on, does the click back and forth you hear translate to a discernible amount of play? very small amounts to play are normal even in low-backlash motors and don't often translate to discernible differences in cut quality with most bits/operations with normal stepover.
there was a time where using a dial indicator to measure the amount of play an axis has seemed like a good method to measure and correct overall play, but overwhelmingly using the push-pull method is the most practical. if push pull doesn't find anything then the issue often is elsewhere (like motor/pinion/rack engagement, tool level, YZ car square/plumb)

Sure, I'll send you the specs. But for the record, it's the original pinions that are a tighter fit (the Browning EN 6418. It is snug enough that it does not click back and forth when you wiggle it on the shaft. The others always have the clicking present....seems too much to me. the newer pinions slide on with no effort. Just want to be sure we're on same page. Thanks a bunch for your support. -SE

[tomhartnett]

Welp, I had it backwards, thanks for clearing it up :cool:

Bigger pinion not being snug is definitely more likely, I couldn't think of a scenario that the 12mm would be bored big enough to fit onto a .5" shaft.
So, still possible the wrong size was sent for the new pinion, we'll get it cleared up. Might be worth it to caliper the ID of the two different pinions, could tell you if one is 1/2" and the other is 12mm?

[sevans]

[QUOTE=TomH,ShopBot;200642]Welp, I had it backwards, thanks for clearing it up :cool:

Bigger pinion not being snug is definitely more likely, I couldn't think of a scenario that the 12mm would be bored big enough to fit onto a .5" shaft.
So, still possible the wrong size was sent for the new pinion, we'll get it cleared up. Might be worth it to caliper the ID of the two different pinions, could tell you if one is 1/2" and the other is 12mm?[/QUOTEIt

It's like the pinion is almost right but not quite.... Not off by much....but different. There are differences in other aspects of the pinion. Feel me?:D

[sevans]

Yes - leave the spindle on there - but there's no problem taking it off. No problem taking off both springs either. It's totally up to you.

In terms of "no matter what the left rollers will never align with the wheels" I need some clarity. Please post a pic or two showing the issue you speak up and explain the problem.

Keep in mind they only used this exact setup for a year or two until SB realized just how much of a cluster it really was...this is not to say it won't be OK, just that there isn't much in terms of documentation - as you've already discovered.

Now just going off of memory here....there is a possibility that the aluminum block(s) that hold the rollers on, somehow walked over . What I mean by that is the AL blocks are bolted to the big plate on the back side. It is possible that the bolts have loosened or walked outboard so that no matter how much you adjust the cams/eccentrics, there isn't enough adjustment.

If you determine that's the case, you'll have to remove the 2 bottom v-rollers from the big plate & lift the entire assembly off the gantry. You may find first removing the spindle & z motor - and just let them lay on the table (and Z motor on top of gantry beam) - and the Zzero plate and Y proximity switch wiring - drape them off to the side (and the Y motor - just watch straining the wires - don't let it dangle). You'll only need some zip ties to get them back on so no big deal.

After the whole deal is off - it will be a lot easier to track down and fix the problem. Don't over-think things - this is strictly a mechanical issue. The fact that it's attached to a robotic tool means nothing...it's easier than working on a riding mower shift linkage or something like that - so dive in. Take pics and video as you disassemble if you're not sure, but....I don't think you need to.

Post back to let me know how you make out.

-B

Hey There, have a quick question for you... I noticed that there are 2 set screws on the insides of the Aluminum Blocks holding the Z Extrusion. Any idea what those are for?