Heatshrink Holders

[MLS]

Greetings.

 

We are looking for a simple way to check heatshrink holders for end of life cycle. Anyone run into these holders eventually degrading and having tools pull out? I thought checking the bore for egg might indicate it was bad, but we have a bad one that is less than .00005" deviation which I imagine is within factory specs.

 

Thanks in advance

[Joe788]

What's the surface finish on the inside look like?

[K2csq7]

Have you contacted the maker of the holders to ask?

[kccadcam]

Has it been overheated?? (cooked)

What's the color of the holder??

[MLS]

Finish on the inside looks fine, the color of the billet ones looks goldish to purple. On the black finish ones, we were told when they begin to crystallize they are done according to the manufacturer. The billet finish ones however don't seem to do this. We have asked them what else to check and got the "Wellllll.... " type answer. And yes... some have been way overheated. Hopefully that problem has been corrected, but it is difficult to tell which have been overheated and which not and to know when they are going to fail until... they fail.... in a part.

[crazy^millman]

Well you could get some carbide blanks and take them over to a press and if they move under a small load those are the bad ones. I cannot remember what the pressure was suppose to be, but that was what I had out guys do to test them at one place I worked.

 

HTH

[MotorCityMinion]

I've never had a tool pull out. From my experience with them, they get tighter, not looser, requiring more heat to use them. We've even jig ground our tight 6mm holders to .25 after they were shot. Got to get them cherry red, but they work.

[MLS]

It does happen on a rather rare basis mostly on big engagement cuts on .750-1.000 diameter holders that are probably close to 5 years old. Problem is we have hundreds of them. I checked out one that recently failed a bit more and found about a .0005" deviation from top to bottom(axially) on the inside so perhaps that is an indicator... Maybe stick a blank in as you suggested Ron and test it...

Hmmmm....

[MrFish]

we have this same problem with our Rineck holders except the cutters tend to spin and then snap rather than pull out. ron's idea sounds like the best test solution.

[Redfire427]

If used properly, a good heat shrink holder should last 10,000 heat cycles. Just one over-heat will render the holder as scrap. You also must have an H7 grade shank for proper interference. I have used heat shrink tools for the last 8 years and never experienced any problems.

 

Carmen