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Thread: Z Adjustment Question

  1. #31
    Join Date
    Dec 2007
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    Appalachian Signs & Design, Boone North Carolina
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    85

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    Quote Originally Posted by Joe Porter View Post
    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

  2. #32
    Join Date
    Jun 2015
    Location
    Durham NC
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    57

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    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)

  3. #33
    Join Date
    Dec 2007
    Location
    Appalachian Signs & Design, Boone North Carolina
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    85

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    Quote Originally Posted by TomH,ShopBot View Post
    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

  4. #34
    Join Date
    Jun 2015
    Location
    Durham NC
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    57

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

    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?

  5. #35
    Join Date
    Dec 2007
    Location
    Appalachian Signs & Design, Boone North Carolina
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    85

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

    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?

  6. #36
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    Dec 2007
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    Quote Originally Posted by Brady Watson View Post
    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?

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