# CNC 6mm endmill failure



## Cncest (Apr 26, 2020)

About 15 minutes in a 6mm endmill failed. Basically the endmill came loose, dropping down into the wood till it shattered. I believe it was due to a combination of dull cutter and loose/worn collet.


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## Cncest (Apr 26, 2020)




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## difalkner (Jan 3, 2012)

Never a good sound or feeling, Dan! Hope nothing critical was damaged.

David


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## Cncest (Apr 26, 2020)

difalkner said:


> Never a good sound or feeling, Dan! Hope nothing critical was damaged.
> 
> David


Nothing critical was lost. There were some lessons learned. New mill, collet and back in business.


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## honesttjohn (Feb 17, 2015)

That's one you should also paint.


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## TimPa (Jan 4, 2011)

WOW, you are doing some great work!


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## Herb Stoops (Aug 28, 2012)

honesttjohn said:


> that's one you should also paint.


no,no,no,no,no!


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## Herb Stoops (Aug 28, 2012)

Cncest said:


> About 15 minutes in a 6mm endmill failed. Basically the endmill came loose, dropping down into the wood till it shattered. I believe it was due to a combination of dull cutter and loose/worn collet.


Make a center punch out of the shank.
Herb


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## RainMan 2.0 (May 6, 2014)

Cncest said:


> Nothing critical was lost. There were some lessons learned. New mill, collet and back in business.


Glad to hear it ended ok . That’s a great piece btw


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## Stick486 (Jan 4, 2013)

honesttjohn said:


> That's one you should also paint.


....


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## sreilly (May 22, 2018)

Seems we have some differing opinions. And yes, I have one as well. There's an old saying in there somewhere but I digress. Paint to me is something that covers up the beauty of the wood and it's grain. If I'm going to paint something it might just as well be plastic or some other material than wood. But again, it's a personal thing. Either way the work itself is fantastic.


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## Leo Yan (May 18, 2020)

Collets have a life span of 400-600 hours, which roughly translates to between two and three months with the collet being used eight hours a day. When inspecting your collet, metallic damage, such as bell mouthing or burrs, should be checked with every tool change.

Glad to hear there is nothing critical, safety is the most important of all work.


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## MEBCWD (Jan 14, 2012)

Nice carving Dan. I want to see that one when it is finished.

Good thing is that you were not hit with any of the bit when it broke and it looks like that was part of the roughing pass where there was plenty of wood. People find it hard to believe that a bit that size can break like that but carbide is brittle and too much deflection and really be bad even on these big bits.


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## JOAT (Apr 9, 2010)

Herb Stoops said:


> no,no,no,no,no!


Yeah, he should hire John to paint it for him.


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