Carbide Inserts - Face Mill Cutter

[Franko]

I'm looking to purchase a face mill cutter. Most come with inserts designated for steel.
I work mostly with aluminum, but occasionally mill some steel.
The inserts are pretty costy, so I'll probably have settle with one type for while.

What are the differences between inserts made for aluminum and steel?
What ugliness results from using one to cut the other?
How about Mitsubishi round inserts?

and...

Is a face mill cutter good for whittling down stock or is there a better option?
It took me more than 2 hours last night to mill down a 1.5" aluminum rod to a 1.1" square using a .75" end mill making two or three .020 passes on each quill adjustment.

I'd also be interested in any suggestions for a good (reasonable) source for a R8 7/16 face mill cutter. I've spotted a couple on eBay. Decent looking 2" tools seem to be going for about $100 - $130 shipped.
My mill is a bench top (not a mini mill) and probably isn't up to anything much larger, unless I'm wrong.

This one looks decent.

http://www.ebay.com/itm/300946022960?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

 

[Ken_Shea]

Franko,
As you likely know insert selection can be very confusing to say the least, this is especially true when you don't work with them on a daily, consequently, my statements are at such a basic level in my shop environment and by no means the last word.

Since that tool uses basic inserts the difference is likely that Aluminum cutting inserts will leave a better finish having a sharper edge then the steel cutting, this edge will dull rather quickly and more prone to chipping when used on steel. A basic steel cutting inserts will cut aluminum just fine, just not as smooth a finish as with the aluminum cutting, still, they leave a very acceptable finish I've found. That said, they make both for a reason and swapping will cut the life and/or performance of each but it's done all the time in a home shop, it's just not ideal. These new high tech performance inserts with special coatings can be very particular in operation.

Another option, you can make a fly cutter of almost any size suitable to your equipment pretty easily and use HSS self ground cutters, these can leave a beautiful finish on both steel and aluminum.

Face mills and/or fly cutters are not heavy cutters nor is a small bench top mill, some times you just have to live with it although almost always, performance improvements are there with attention to cutting factors. One big mistake I read about is running too slow a RPM, with aluminum you can almost always run full RPM with appropriate smaller end mills 1/2 or smaller and 2/3 flutes

This is one of those threads where there is no good place to stop talking with SOOOOO many variable in play.

 

[Franko]

Thanks, Ken. Sharper finer edge. That makes sense.

What I was hoping is that a face mill cutter is a better tool for hogging off a lot of material and would be capable of taking deeper cuts than a fly cutter whacking on the edges of the part.

 

[pineyfolks]

I've seen a lot of face mills that looked to be a great deal until I priced the inserts. If you use inserts on your lathe maybe you could make a fly cutter using the same toolholder.

 

[Cobra]

My facemill is more rigid than my fly cutters so will take a deeper cut but the real advantage seems to be the feed rate.
Because of the multiple cutters on the facemill, you can feed faster and still keep the same load on the cutting tool.
As noted above, I just use the one set of inserts for all materials. Seems to work fine for me.

 

[Franko]

Thanks, Bill, Jim.

The face mill I'm watching on eBay comes with 10 rectangular inserts. They look like they have different profiles on opposing corners but since the inserts are rectangular, so I suppose there are only 2 usable cutting corners. The inserts are TIN coated carbide. I'm not sure that I get why there is any advantage in coating a carbide tool with TIN.

It is only $120 shipped from Hong Kong, but it looks decently made with good finish.

 

[aliva]

If you intend to remove a lot of stock, I've used a roughing end mill first, then switch to a face mill, or fly cutter, for the finishing passes.
Better yet, if you can band saw most of the stock first you could save a lot of time and effort.

 

[Franko]

Is the end of a roughing end mill any different from a normal end mill?

I generally try to cut work pieces as close as I can to avoid have to mill any more than I have to, but sometimes the blank needs to be very symmetrical to achieve the end result. What got me thinking of this is a project I did Thursday, where I had to cut .255 off four sides of a round rod, so it was cut and turn, rinse and repeat four times.

 

[Cobra]

The coating is not TIN, but TiN(TitaniumNitride), a ceramic that is vapor deposited on the surface of the carbide. It dramatically extends the life of the cutters by increasing the hardness of the cutter surface and increasing the lubricity of the surface.
I picked up two 3 inch facemills from CDCO (one 75 degree, one 90 degree) for about $65 a piece and an arbor for about $25. They have worked well for me. One of them uses triangular inserts, the other is square. Not cheap for the inserts but the do last well.

 

[JimDawson]

Is the end of a roughing end mill any different from a normal end mill?

From a functional standpoint, not really. The tooth shape is a bit is a bit rounded as opposed to a sharp corner in all but finishing roughers which do have a sharp corner.