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Shell Mill vs. Face Mill vs. Boring/Facing Mill?

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H-M Supporter - Premium Member
H-M Supporter-Premium Member
Feb 2, 2017
My new-to-me mill needs tooling. I've got some basic end mills coming (Chinese HSS) to learn on, and local benefactors will set me up with a fly cutter and more mills.

I think I need (want) something beyond a fly cutter to remove material from the top surface. I also need (want) a good boring head. I'd planned on picking up a used Sandvik or equivalent shell mill and a Criterion boring head, but when I started looking at Ebay the choices were overwhelming. Then I came across Wohlhaupter boring/facing heads (I'm sure there are others), further confusing me.

I've checked out a few videos and Googled like crazy (including searching here), but all I learned was that shell mills can face and side cut, while face mills are largely for finishing. Is there a primer on more advanced tooling that talks about pros/cons of shapes, number of inserts, shape of insert (square, hex, round, triangle)?

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Active User
H-M Supporter-Premium Member
Dec 20, 2012
Hey Evan, I have some comments to share.

Boring head: who would not want a Wohlhaupter boring/facing head? The problem is cost, and a complete setup will run near $800.00 on ebay if you find a good deal on a good one. Even the little UPA3's are big bucks. I want one but will probably never own one. I think a Criterion DBL-202 is a very good head for general use in a hobby shop. This is a 2" head that you can probably get close to max extension without the mill walking across the shop floor. It will bore out to 3" with the bar in the outer hole and out to 6.687" with a bar in the horizontal hole. The DBL-202 comes in A (uses 3/8" shank bars) and B (uses 1/2" shank bars) models. These heads are threaded 7/8-20 so different mounts can be used with it.

I don't use face mills or shell mills, although some guys seem to really like them. They take a lot of power to run and getting the inserts equalized on the indexable ones can be a bit finicky. I'm probably in the minority but I prefer a fly cutter for squaring stuff and get pretty good finishes that way. Not saying a fly cutter is the way to go; just that it is what I have come to prefer.

Outfitting a new mill can be expensive. When I think of end mills, I think HSS or cobalt, not carbide. When I think of boring heads, I think of Criterion instead of Wohlhaupter/Kaiser. When I think of surfacing, I think of fly cutters instead of face mills. Just wanted you to have one perspective on things.
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