# End mill tool holding



## dlinva (Jun 14, 2021)

Trying to sort out which method I should be using to hold end mills. I have a basic set of R8 collets, but reading up on those, they are not too 'compressible' and some of my end mills seem a little loose in the same size R8 collet. Should I try to get end mill holders? Or should I start to think about ER collets. Most of my milling will probably be in aluminum, but I don't want to be limited to just that. Any guidance would be appreciated...tooling costs money!


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## Mini Cooper S (Jun 14, 2021)

R8 have been the standard for a long time. What exactly do you mean by 'a little loose"? Although not ideal, I have held thinks up to .02" smaller than the collet size, drills for instance. 
Richard


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## RJSakowski (Jun 14, 2021)

I have used R8 collets for both end mills and drills for the past forty years.  My R8 collet set is by 1/32nds and they do an acceptable job for the most part. End mills typically come with standard size shanks and for inch sized end mills, they should fit inch sized collets well.  If you are using metric tooling, you might want to invest in some metric R8 collets.
End mill holders are intended for use with Weldon style end mills which have a ground flat on the shank.  They are also a close fit for the tool shank.  Otherwise, there would be unacceptable runout.  End mill holders are great for aggressive cuts where a tool might spin or pull out in a collet.  I have R8 end mill holders in 3/16, 1/4, 3/8, 1/2, & 5/8 sizes, as well as 1/2, 5/8, & 3/4" chucks but most used are the collets.


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## Buffalo21 (Jun 14, 2021)

I have R8 collets, ER collets and Din 6388/EOC/SYOZ style collets, If I have a clean collet and a clean end mill, I’ve never had a end mill slip in a collet. no matter how deep or aggressive the cut. As a large percentage of my use is with a carbide end mills, I don’t use end mill holders, as carbide end mills do not have the Weldon pocket cut into the end mill shank. I got rid of my end mill holders , as certain ones caused a excessive vibration in the mill head,  IMO they protrude too far for my liking out of the spindle, possibly cheap holders.


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## homebrewed (Jun 14, 2021)

I have an ER set and a few larger R8 collets to hold my larger end mills.  Never had a problem with end mills slipping.  One significant difference (to me):  R8 collets stick out of the spindle less so I gain more Z capacity.  I have a small benchtop mill with not much Z to start with.

Whatever type you get, be sure to include a collet that can hold an edge finder and your dial test indicator(s).  I can use the same collet size for both of mine and that's a time-saver for sure.  I'm just a hobbyist but still appreciate that, since it means I can be making chips sooner.


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## epanzella (Jun 16, 2021)

I got a set of ER32's and never looked back. Being double slotted they gave a greater range than R-8's. My set is by 32'ds and each collet's range extends to the one above and below it so you can grab anything within the total range of the set. I still use my R-8's on occasion like when using a face mill or fly cutter but the ER32 set is my GO TO.


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