Breaking Guide Bushings on Swiss Lathes
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  1. #1
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    Default Breaking Guide Bushings on Swiss Lathes

    Hello,

    We are having an issue that has us scratching our heads, we have some Tsugami Swiss machines and one of them has started to break the guide bushings pretty frequently. we have verified that the tools are not hitting it, we are thinking it is from vibration but do not know how to confirm that. My question is, what are some of the possible problems that could cause the guide bushing to break?

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    Quote Originally Posted by David.Losee View Post
    Hello,

    We are having an issue that has us scratching our heads, we have some Tsugami Swiss machines and one of them has started to break the guide bushings pretty frequently. we have verified that the tools are not hitting it, we are thinking it is from vibration but do not know how to confirm that. My question is, what are some of the possible problems that could cause the guide bushing to break?
    Out of round or bent bar stock? Have you checked your materials, or changed suppliers recently?

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    How are they breaking?

    I've never seen a guide bushing break before.

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    Quote Originally Posted by Milland View Post
    Out of round or bent bar stock? Have you checked your materials, or changed suppliers recently?
    Out of round can mike round if centerless ground. Need a a V angle mike or a V-block and indicator to check for this. I have some boring bars that were centerless ground tri-lobed and .002 oversize. They mike fine with a conventional mike because there is a low spot opposite each high spot. Look for a Starrett #483 or equivalent mike.

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  6. #5
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    I've had the carbide pads in the bushing get cracks in them. That has only happened from pretty major crashes, though. I don't know how the bushing could get damaged with normal use.

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    Misalignment of main collet and guide bush, stock not round good enough, guide bush adjusted too tightly, too big forces from front causing stock to bend in an S. BTDT

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    I would check barfeeder alignment and Z axis main spindle alignment. It sounds like someone drove a forklift into the barfeeder or you probably had a crash that requires the Z on the main spindle to be realigned.

    Are you using a rotary guide bushing? I haven't witnessed it, but I suspect if the bearings were really clapped out or it lost its preload I could see that causing problems ... although I would think you would be blowing up inserts and tool holders as well.

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  10. #8
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    What model Tsugami is it? What size bar? When you jog in Z what percentage load do you see in the MONI screen?

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    thank you, this would make sense, i'm not sure how but we recently had a crash that broke the key in the spindle, I will have to see if I can find how to check the alignment and also the bearings.

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    thank you, I will have to look into checking the percentage load. its a Tsugami BS12-V with .5 bar stock.

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    Quote Originally Posted by David.Losee View Post
    broke the key in the spindle
    The little key that the slot in the guide bushing slides over or the key that the slot in the main collet sleeve slides over? Hmmm, yeah I wonder if the spindle and GB aren’t in alignment.


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