[JWB_Machining]

Hey, My Haas training technician told me that I should use ER-16 Collets for holding drills but not end mills. Can anyone clarify why I shouldn't use ER-16 collets for end mills and does that Mean I shouldn't use ER-32 Collets for End Mills as well or are they ok to use?

-JWB

[Geof]

I no longer use an ER16 collet for a 3/8 end mill taking a good healthy cut; it turns the collet into a helix when the cutter breaks.

For anything smaller there is no reason not to use ER16, and even for 3/8 an ER16 is needed when there is simply not enough room in a fixture or the part for a bigger collet nose.

[ckirchen]

I ran an endmill in an ER-16 collet all day long yesterday. Not sure why the tech would recommend not to. In my opinion, it's perfectly acceptable practice.

[scadvice]

... is about .375. The upper limit...that means you baby it a little at that size.
To me that is a max .006 chip load per tooth on a 3 flt. in alum. as fast a RPM as your machine can handle. 65% engagement and 50% diameter DOC. Climb cut only. Also a stub EM.
Steel .003 per tooth 4 flt. 1800 to 2400 RPM (Dep. on Alloy coated with radius cnrs.). 75% engagement and 33% DOC. Climb cut is best. Stub or standard.
A properly installed cutter in a ER-16 collet will run without problems at those sittings ( With some minor tuning).
ER-16 collets need to be a good brand. There are some out there now that are crap. Material and run-out. The good ones will run very true .0002 tenths one inch out. The only problems I've ever had have been with a ER from India and China. Sorry guys from India...mainland China too.
I will not use them for drilling unless I use a new drill and I stone the lettering down if it is raised. Normally, I do not use them for drilling they cost to much for that.
If you are really trying to push a .375 EM then step up to a ER-20.
My thoughts anyway and that tech has no clue. - Steve

[ALLtra Mach]

I've ran lots of end mills in ER collets.
However, you will not get the performance that you would out of your mills if they were in a more ridgid set up than ER, regardless of size. That boils down to a cost versus production matter.
I won't remark on the Hass part of the equation.

[ktm666]

er collets are not the most precise of the bunch. in my opinion shrink fit tooling is the only way to go for solid carbide cutters.

[Andre' B]

er collets are not the most precise of the bunch. in my opinion shrink fit tooling is the only way to go for solid carbide cutters.

These work fine.
http://www.gohpi.com/HPI2007Update0807MX.pdf

[ckirchen]

er collets are not the most precise of the bunch. in my opinion shrink fit tooling is the only way to go for solid carbide cutters.

I've read that hydraulic holders (such as those from www.schunk-usa.com) rival shrink fit holders.

Chris Kirchen

[Astonlee]

There is no reason why you shouldn’t use ER16 double angle collets for milling like most things “if you buy good quality collets” However make that you size for size collet e.g. ER collet have 1mm of collapse, so do not use Ǿ7mm collet for a Ǿ6mm milling cutter otherwise you are asking for trouble. You can double the clamping force of ER collets by using chucks fitted with a “bearing nut”, as it overcome the friction created between collet & nut when tightening, and double the clamping force. This is an editorial link on benefit of using precision collets on tool-life: http://www.mctooling.com/index/listings/page972.htm

[Astonlee]

Shrink work brilliantly on all milling application apart from solid carbide ripper cutters. As I use to work for a specialist high-speed/performance cutting tool company. We first starting using/selling shrink-fit over 15 years ago, but kept having mixed results when started applying solid carbide ripper made by a really high-quality Swiss manufacturer.
They kept telling us to only use side-lock, and we kept arguing with them they were wrong, in the end they came over a ran extensive trials using our Mori VMC, but they were right even with shrink-fit you can get micro-slippage of the tool in extreme applications, from then on we only use the ripper in side-locks and never had a problem again using their rippers.

[Astonlee]

Hydraulic holders were designed for use in precision drilling application and their TIR matches that of shrink-fit. They are suitable light to medium milling application, but not for taking heavy side cutting as they will flex, and allow the cutter to push over.

[enauman]

Is there a difference between an ER-16 and an ER-16A? I've seen both nomenclatures. Another question: is the bevel in the ER clamping nut supposed to be ground off center?

[ckirchen]

The bevel in the nut is supposed to be centered; the lip is the part that is off center. This eccentric lip is what unseats the collet when you undo the nut. Without the lip, it would be impossible to pull the collet out by hand after it has been tightened.

[ALLtra Mach]

We have been looking at REGO- FIX Power grippers. They claim to be better than Shrink fit. But like shrink fit, they are expensive.
Once again use High quality ER collets.

[ktm666]

those hpi mx collets are money for smaller cutters. i wouldnt go over 8mils or 3/8.