Breaking Guide Bushings on Swiss Lathes

D

David.Losee

Plastic

Joined

Jul 19, 2021

• Jul 19, 2021

• #1

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?

 

M

Milland

Diamond

Joined

Jul 6, 2006

Location

Hillsboro, New Hampshire

• Jul 19, 2021

• #2

David.Losee said:

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?

Click to expand...

Out of round or bent bar stock? Have you checked your materials, or changed suppliers recently?

 

TeachMePlease

Diamond

Joined

Feb 11, 2014

Location

FL

• Jul 19, 2021

• #3

How are they breaking?

I've never seen a guide bushing break before.

 

F

FredC

Diamond

Joined

Oct 29, 2010

Location

Dewees Texas

• Jul 19, 2021

• #4

Milland said:

Out of round or bent bar stock? Have you checked your materials, or changed suppliers recently?

Click to expand...

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.

 

W

wmpy

Hot Rolled

Joined

Dec 16, 2011

• Jul 19, 2021

• #5

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.

 

Mechanola

Stainless

Joined

Mar 21, 2011

Location

Äsch

• Jul 20, 2021

• #6

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

 

E

enginuity

Aluminum

Joined

Dec 23, 2009

Location

Canada

• Jul 20, 2021

• #7

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.

 

Nerdlinger

Stainless

Joined

Aug 10, 2013

Location

Chicago, IL

• Jul 20, 2021

• #8

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

 

D

David.Losee

Plastic

Joined

Jul 19, 2021

• Jul 22, 2021

• #9

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.

 

D

David.Losee

Plastic

Joined

Jul 19, 2021

• Jul 22, 2021

• #10

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

 

Nerdlinger

Stainless

Joined

Aug 10, 2013

Location

Chicago, IL

• Jul 24, 2021

• #11

David.Losee said:

broke the key in the spindle

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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.