Holding End Mills?

What works is machine and individual specific. If ER32 is the most convenient then use that, at the end of the day it will not make any difference in the ability to hold an end mill in your mill. You are mostly limited by the design of the mill as to rigidity and TIR. When I had a bench mill w/o a power drawbar I used an ER-32 system because it was the easiest. An ER-32 system will hold tighter tolerances than a R-8 collet system, in particular with the less expensive collets. When I moved to a knee mill with a power drawbar, I have not touched my ER collets and primarily use a CNC chuck and a set of Lindex R-8 collets because the ER system is much less convenient. I use dedicated R-8 holders for my annular cutters and face mills. If I had a larger mill than the R-8 system becomes the limiting factor.

You do not need an extensive set of ER collets if using them with most end mills, as the shanks tend to be standard sizes, so something like a 1/8" increment set is fine. If you have an odd ball size you can use the chuck or just get a full imperial sized ER collet set. I will mention that often a metric 1 mm increment ER set is sold because it covers the full clamping range of the collet system, but the clamping range depends on the quality of the collet and the TIR can be pretty terrible at the extremes of the clamping range. I would go with an imperial set, surprised at how inexpensive they are. On the R-8 holder I prefer the nickle plated precision versions, the Shar's one that I use has a TIR ~ 0.0001" and you aren't going to get much better than that. A coated or ball bearing nuts makes tightening easier and can improve accuracy but they are not inexpensive. You need to buy a wrench for the specific nut you will be using.
www.ebay.com

22pcs/set ER32 COLLET SET Complete Sizes including all 16th & 32nds --New | eBay

22 PCS Complete Sizes ER32 COLLETS CONSISTS OF: 1/8,3/16,1/4,5/16,3/8,7/16,1/2,9/16,5/8,11/16,3/4, 5/32,7/32,9/32,11/32,13/32, 15/32,17/32,19/32, 21/32, 23/32, 25/32, 22pcs total. YOU CAN CHANGE THE COMBINATION OF THESE 22 COLLET SIZES.
www.ebay.com

R8 ER32 ER Collet Chuck Tool Holder .0001"

<!-- <ul><li>Shank: R8</li><li>Type: ER-32</li><li>Drawbar End: 7/16"-20</li><li>Runout: 0.0001"<br /></li></ul> -->
www.shars.com www.shars.com
 
I say go both ways. The ER 32 has the advantage you can mount up to just up to under 1”. Then if you have adapters for the headstock and tailstock on your lathe. You also have collets for that use. On those round column mills it may be a good option.

Then you can buy some R8 collets. But you could get by just the common fractional sizes. The your ER 32 will cover the odd gaps.


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I vote for just three R8 collets: 1/4", 3/8", 1/2" , for now. Drill chuck with 1/2" or R8 shank. Maybe get into ER stuff later.
 
markba633csi said:
or now. Drill chuck with 1/2" or R8 shank
Click to expand...

I have a great 0 to 3/8 chuck with a 1 1/4 long half inch shank that I use in my mill. The 3 1/2 shank that came with it was ridiculously long, and the 1/2" R8 collet only has an inch of contact length anyway.
 
For me, R8 collets were ok but once I converted to CNC I went with Tormach TTS adapter and ER20 collets (as RJ did above). Haven't looked back since- the convenience and speed of switching tools doesn't get any better short of having an automatic tool changer.

However, as someone above suggested most of your tooling will likely be 1/4, 3/8 and 1/2 so you can start with a small set of R8s for now and then upgrade to ER later.
 
I get paid to mill every day. We have no ER's for R8 spindles at all. I have 4 endmill holders of my own 1/8", 1/4", 3/8", and 1/2". As suggested above, very handy reaching into recesses, being smaller diameter than spindle nose. Everything else is R8 collets. Shop has no small endmill holders, we occasionally use 7/8" and 1" with large roughers facing off square, taking small cuts and the spindle fully retracted. Those are last ditch remedies, most often a long 3/4" rougher suffices.
A drill chuck is not a satisfactory endmill holder what-so-ever. Some drive taps that way. Not good either as a spun tap [higher Rc hardness] galls the jaws, which in turn ruins drill shanks being lower Rc.
 
For now I've decided to get a set of South Bend R8 collets by 16ths and three R8 end mill holders in 5/8", 3/4" and 1". I've got a drawer full of endmills with shanks in those three sizes. Experience will tell me if I need ER collets and time will allow me to get good ones if I need them. Thanks to you all for the priceless information!
 
Like I said , been in this trade for 45 years now and never used ER collets in a mill other than cnc machining centers .
 
Late to this but I'll chime in my $.02

I also have an RF30 mill. I chose to get the ER32 collet system, along with a metric set of collets. The metric set I have goes from around 3mm to 20mm and are sized by mm increments. So I have a collet that fits 7-8mm the next is for 9-10mm. The cap/closer on the collet chuck can possibly get in the way, but I've not run into that yet. I felt like this system was good enough for me. I also use these collets for holding drills and rarely now put the drill chuck in place.

I am just a hobby guy. I don't make any money on what I do in the shop, in fact the machine work just supports my other hobbies and keeps me going without having to pay someone else. My goal when getting into this was to hold .005" on what I do, both lathe and mill. I was able to realize that goal pretty quickly with the tooling I have. I have only found a few times when I needed more than that, but I have been able to hold .002" on the mill when I needed to, and that was using the ER32 system.

Hope this helps
 
I have collets and end mill holders for my R8 mill. I always use end mill holders with steel end mllls for the simple reason that collets hold just by friction and end mill holders hold solidly with a set screw on the flat of the end mill. My carbide end mills, however, are mostly without the flats, so I use collets with them so as not to put point-load from the set screw onto the brittle carbide.
 
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