Shell Mills and Face Mills for R8

erikmannie

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So I am thinking about obtaining a shell mill or face mill for my 1 HP milling machine. I want to make sure that the parts that I buy fit together and will work in my machine.

I looked online, and I see that the cutting tools have a shank diameter as well as a cutting diameter.

I see that the arbors have a shank diameter as well as a projection.

I will probably start with one arbor and one HSS shell mill because I am low on funds. I have an R8 taper.

Questions:
(1) I usually work on mild steel. Is there a maximum diameter of cutting tool for use with a 1 HP motor?
(2) Why do these shell mills have cutting edges on the side? I thought they were only for facing.
(3) Am I wasting my money choosing HSS? I don’t think I can afford carbide at this point.
(4) I will match the shank diameter, but do I need to match the height of the shell mill with the projection of the arbor?
(5) I already have a fly cutter. It is pretty slow.
(6) I would be using this to provide a flat surface on boxes that I make. My end mills go up to 3/4”, and I probably don’t want to buy a face mill. I am thinking that I want to buy a HSS shell mill.
 
Shell mills take HP , you're better off with an insert cutter of desired diameter .
 
If you are just flattening a place, the fly cutter isn't a bad choice. The issue I have with shell mills is that they take more energy to make work than I have for the sizes I would need. Insert carbide face mills are nice, if you lack power just remove inserts until you get to where it works for you. If you remove all but one insert it becomes a fly cutter essentially.

I have also used insert and brazed carbide in my fly cutters. Works well and gives you a little faster cut but it can be hard on carbide of you try to do too deep a cut or get to fast speeds or feeds.
 
Questions:
(1) I usually work on mild steel. Is there a maximum diameter of cutting tool for use with a 1 HP motor?
For most work I don't use larger than 1/2'' on my 3500LB, 3 HP mill, and 1 1/2'' on my 7.5 HP mill.

(2) Why do these shell mills have cutting edges on the side? I thought they were only for facing.
Because they are essentially big end mills and cut on the side also. If you have enough power and a heavy enough machine you could cut full depth with one.

(3) Am I wasting my money choosing HSS? I don’t think I can afford carbide at this point.
Yes

(4) I will match the shank diameter, but do I need to match the height of the shell mill with the projection of the arbor?
Not sure what you mean here.

(5) I already have a fly cutter. It is pretty slow.
Most likely the best option for wide facing passes.

(6) I would be using this to provide a flat surface on boxes that I make. My end mills go up to 3/4”, and I probably don’t want to buy a face mill. I am thinking that I want to buy a HSS shell mill.
A face mill would be a better choice.

Something like these would be a good choice. Not larger than 2 inch. https://www.amazon.com/Accusize-Ind..._1_6?keywords=face+mill&qid=1584679938&sr=8-6
 
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I've had issues in the past with HSS in a flycutter work hardening 1018. Unless you have low RPMs, I'd prefer brazed carbide in a flycutter. Tormach's insert flycutter is also very good on aluminum—the high take ground inserts are da bomb for aluminum.

Sent from my Pixel XL using Tapatalk
 
You have a small mill with a limited budget. If I were you, I would consider the Tormach Superfly that uses a single insert. Tormach came up with it as an alternative to their face mills when used on a low HP mill. It works quite well with a 1HP motor, can do a surprising amount of stock reduction and finishes better than their 38mm face mill. Inserts are pretty cheap and last quite some time in a hobby shop. I've done a 0.070" deep pass with that thing and it left a more than acceptable finish.
 
Looks like the Tormach Superfly is not available for an R8 taper.

Sounds like HSS is not a good road to go down here.

I liked the carbide indexable cutter in the Amazon link by JimDawson, but maybe I should get smaller than 2” for the 1 HP machine.
 
1 HP will turn that 2" insert cutter .

Great! Carbide it is.

I’m not going to buy this, but it looks to me like something that might not be the best choice.

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