# Shell Mills and Face Mills for R8



## erikmannie (Mar 20, 2020)

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.


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## mmcmdl (Mar 20, 2020)

Shell mills take HP , you're better off with an insert cutter of desired diameter .


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## MontanaLon (Mar 20, 2020)

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.


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## JimDawson (Mar 20, 2020)

erikmannie said:


> 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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## pstemari (Mar 20, 2020)

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


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## mikey (Mar 20, 2020)

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.


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## erikmannie (Mar 20, 2020)

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.


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## mmcmdl (Mar 20, 2020)

1 HP will turn that 2" insert cutter .


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## davidpbest (Mar 20, 2020)

Get the R8 TSS collet and use the Superfly.


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## erikmannie (Mar 20, 2020)

mmcmdl said:


> 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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## erikmannie (Mar 20, 2020)

davidpbest said:


> Get the R8 TSS collet and use the Superfly.




I was wondering how to adapt the TTS to R8, but I was afraid to ask. Thank you.


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## mmcmdl (Mar 20, 2020)

Well , sure that would work , but that thing is weak . You could make a much better 2 tool fly cutter than that .


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## erikmannie (Mar 20, 2020)

We have a winner, but I will have to save up.

I’ll bet there are a number of TTS tools that can fit into this collet, possible rabbit hole here.


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## erikmannie (Mar 20, 2020)

The last thing that I would need is to try and cut work hardened 1018!


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## erikmannie (Mar 20, 2020)

That thing just looks like a bad idea. You would really have to set the tools to the same height.


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## mikey (Mar 20, 2020)

You can actually use the Superfly in a regular 3/4" R8 collet but it may not hold as solidly or as well. I suggest you buy the TTS R8 collet at the same time you get the Superfly. That collet will hold any of the other tools in the TTS system, not just the Superfly, so its not a bad idea to have it. Once you see how fast and simple it is to change tools with the TTS system you'll see why many of us use it.


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## machPete99 (Mar 20, 2020)

I have the 2" FM45 cutter from Glacern, its very nice, and is the single piece integrated R8 arbor so is fairly rigid. It uses more rake so is shearing rather than beating the metal off. Its not intended for hogging, but you can maybe take up to .020 in a pass without trouble. Leaves a fine polished looking finish. This is used on my "hotrodded" 1HP Rockwell mill.






						Glacern Machine Tools - FM45 Facemills
					

Glacern Machine Tools manufacturers CNC Machine Vises, Precision Tool Holders, and Indexable Milling Cutters for vertical and horizontal cnc milling machines.




					www.glacern.com


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## ddickey (Mar 20, 2020)

You can just buy the Superfly tool holder and make your own.


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## bakrch (Mar 20, 2020)

I have the 38mm Tormach face mill and never use it on my PM25. A fly cutter works much, much, much, much better for this level of machine. Even still, I find myself doing most of my facing with a 1/2" end mill.


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## DavidR8 (May 2, 2020)

mikey said:


> 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.


Do you know if the Tormach fly cutter toolholder would work in a non-Tormach fly cutter body?


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## mikey (May 3, 2020)

The tool holder is angled such that the tip of the insert makes flat contact on the cutting edge so unless yours happens to be at the same angle, I don't think it will work.


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## mikey (May 3, 2020)

DavidR8 said:


> Do you know if the Tormach fly cutter toolholder would work in a non-Tormach fly cutter body?



Dave, after thinking about it, I responded without thinking things through. It may be possible to modify your current flycutter to accept the Superfly tool holder IF the body of your flycutter is not hardened. You may be able to modify the width and angle of the tool holder slot to accept the Superfly tool holder so that the insert works at the correct angle. If you wish to do this, I can measure the angle of the Superfly fly cutter body for you so you can give it a shot. Let me know.


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## DavidR8 (May 3, 2020)

mikey said:


> Dave, after thinking about it, I responded without thinking things through. It may be possible to modify your current flycutter to accept the Superfly tool holder IF the body of your flycutter is not hardened. You may be able to modify the width and angle of the tool holder slot to accept the Superfly tool holder so that the insert works at the correct angle. If you wish to do this, I can measure the angle of the Superfly fly cutter body for you so you can give it a shot. Let me know.


That'd be really great if you would measure the angle. Buying the Superfly is about $230 CDN vs just the tool holder for about $110 CDN


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## mikey (May 3, 2020)

Okay, I measured the angle with a Starrett vernier protractor and got a 20 degree angle from the horizontal plane or 70 degrees from the vertical plane, depending on how you prefer to orient the angle. See pic from our very own @BGHansen:




The tool holder itself is 0.3890" square and the slot is 0.4065" wide. 

Hope this helps, Dave.


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## DavidR8 (May 3, 2020)

mikey said:


> Okay, I measured the angle with a Starrett vernier protractor and got a 20 degree angle from the horizontal plane or 70 degrees from the vertical plane, depending on how you prefer to orient the angle. See pic from our very own @BGHansen:
> 
> View attachment 323047
> 
> ...


That's a tremendous help, thanks very much, As always I really appreciate it!
@BGHansen thanks for your post too!
D


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## Aaron_W (May 5, 2020)

mikey said:


> Okay, I measured the angle with a Starrett vernier protractor and got a 20 degree angle from the horizontal plane or 70 degrees from the vertical plane, depending on how you prefer to orient the angle. See pic from our very own @BGHansen:
> 
> View attachment 323047
> 
> ...



You've also mentioned you like the Sherline insert fly cutter for your RF-31. How does the Superfly compare / when do you use one vs the other?

Sherline now offers the insert flycutter with a straight shank making it easier to adapt to other small mills. About 1/2 the cost of the Superfly.




Sherline single flute insert fly cutter with straight shank


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## mikey (May 5, 2020)

I actually use the Sherline flycutter a lot, especially if I need to cut to a shoulder or make a ledge. It is really a single flute face mill that cuts a 1-1/8" swath so it's small but it works really well. It allows you to cut at high speeds so it finishes well, too.

The only time I prefer the Superfly is when I need to flatten a larger surface area. Otherwise, I use the Sherline tool. Now that they offer one with a straight shank, I'll buy one and use it in an ER collet for better accuracy.

EDIT: Just bought the straight shank version. Yeah, it's worth the cost.


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## Buffalo21 (May 5, 2020)

I have 4 face mills, that I run on 3 different milling machines, a Rockwell (1hp), a Jet (2 hp) and the Franken-Mill (2hp), 2 of the face mills are 2” and the other 2 face mills are 2-1/2”. The best ones I own are the 2 of the 2”, one is a Walter F4041 and the other is a BangGood one, using APKT inserts. The Walter is a high buck unit, where the inserts are $25/ea, is a true metal eating monster, even at 1 hp, the BangGood one is a very good unit, removes metal fast and leaves a good finish, it also runs well at 1hp. The 2-1/2” face mills are pushing the of capacity even the 2 hp mills, could be the insert type or the extra diameter.


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## theperfessor (May 6, 2020)

I have all sorts of carbide insert mills for my knee mill, the smallest (and extermely useful) being a 1-1/4" two flute cutter that uses a TPU/TPG insert. Positive rake, cheap insert, smallish size for lower HP machines, square shoulder. Got it from Enco years ago, but they're still available thru many vendors. Here is a link to the R8 shank/ TPU insert mills at Shars:






						shars.com - Indexable Milling Cutters
					

Shop Shars Tool today and see why customers choose our high quality milling cutters at a great value, same-day shipping and dedicated customer support




					www.shars.com


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## speedybtx (May 7, 2020)

the 2" FM45 cutter from Glacern, its very nice 


It more than nice ! it is what the OP needs !    Fantastic finish can be had.


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## machPete99 (May 8, 2020)

I also have the Glacern FM45 and concur that it is very nice, produces very good finishes, even on partially hardened tool steels (4140PH, etc). It likes skim cuts though, its not for hogging.


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