[Newbie] Shell Mill Selection

[tfleming]

I am looking to buy a small 2" +/- shell mill for doing light facing work on some antique hit and miss engine heads. Material will be cast iron. Basically, looking to clean up gasket areas. I am debating between a fly cutter or a shell mill. If I go with the shell mill, I then need to decide between a 3 cutter or 4 cutter config. My small vertical mill has a MT2 spindle.

My gut is telling me shell mill with 4 cutters. However, I have been soliciting some feedback from other friends, some of which have suggested the fly cutter solution.

Anyone have suggestions or guidance before I spend $$$ on tooling?

 

[carlquib]

A fly cutter would be much cheaper and can give a nice finish for not a lot of expense, a little slower than a multicutter shell mill. You can also grind your own cutters for a simple fly cutter. Shell mills on the other hand can be quite pricey and either hard to sharpen without a tool and cutter grinder or expensive to change inserts. With a morse number two you couldn't really take advantage of a shell mill, just don't have enough rigidity. However, if you want a shell mill, just because, go for it.

Hello, my name is Brian and I'm a toolaholic!

 

[David VanNorman]

I'am with Brian the fly cutter is the way to go. It will take less power to run and will give a good finish.

 

[chevydyl]

The more teeth the harder it is on your machine when it comes to the pounding of each tooth as it goes off the material and back on, my mill has a little slop in one of the keys, and it loud with my 6 tooth face mill. On your machine I would go fly cutter, as said rigidity is not your friend.
But, if your dead set on getting a shell/face mill, contact mitsubishi, they have a deal where you buy a 10 pack of inserts and get a free cutter, I think it's setup for 1 pack per inch, I have a 3inch mitusbishi, 6 tooth, 4 cutting edges per insert, I have never even changed or rotated to a new cutting edge, and I've ran it through torch cut edges plenty, if you go that route I'd recommend the JL chip breaker, I use nx4545 cermets. Mitsubishi can better help you decide on what to get concerning the type of insert, but I'd stick with the JL, it's for light cutting, don't get hung up on buying the cast iron inserts, the steel ones will work great, your not doing production. These inserts leave a mirror finish on steel.

 

[tfleming]

Thanks for all the responses. Fly cutter it is! I have been using a lathe now for a few years and have gotten pretty comfortable with tooling for it. I just bought a small vertical mill a few weeks back, and it is my first foray into milling. thanks for the guidance and suggestions! As I said, the majority of what I will be doing will be cast iron on the old engines I work on. I am NOT doing production work, just resurrection of the old iron (antique tractors and hit miss engines).

I have done some milling on my QC54 Atlas lathe with the milling attachment, but that has been very limited due to the small size of the milling attachment. My mill is an Atlas horizontal mill that has been converted to a full time vertical mill. The conversion was done by an old time tool maker who was into making small V-8 engines. While the machine is relatively small, it is plenty large enough for what I have intended for it, and the man who made it did a really nice job. I have started with the ER20 collets and a couple of rigid mill holders for most of my tooling and I am looking forward to making chips a different way! thanks again to all the replies!

 

[barnett]

Hello, my name is Brian and I'm a toolaholic!

I fit that description too .

 

[joshua43214]

I like fly cutters a lot, but I have been considering a shell mill for quite a while.
@chevydyl thanks for the tip on the Mitsubishi stuff. Will check that out.

I find I get the best results on cast iron with 0 rake, and always cutting at least as deep as the radius on my tool. Fly cutters are really nice because you can easily put a very tiny radius on the tool, and take very light cuts.