do I "need" a fly cutter, if I have a face mill

[mike-sid]

I saw one of Tom's YouTube videos, and He was using a fly cutter. I have a 2" face mill, Valenite V555, seems like they do the same operation. Is this correct? Or are they suited for different uses?

[EdK]

I also have a face mill and take all but one insert out. It works similar to a fly cutter that way and there's less load on my small mill.

Ed

[DaveH]

Mike,
Yes they do the same job.

Not all of us can afford a 2" face mill, also a 2" face mill needs spindle power and a rigid machine.
Fly cutters can be made in the home work shop and are very suited to small, bench top low power machines.
 
DaveH

[f350ca]

I use a fly cutter if I want to surface something large in a single pass. They take relatively little power, so say a 6 inch dia cutter can be used inside of 3 passes with your 2 inch shell mill.

[Arbalest]

They are also very inexpensive to "run" using a single piece of easily resharpened HSS.
You can use inserts in them as well though with the right holder, for use on tough materials.

A quick google throws up images like this monster!:

[Arbalest]

Nice finish!

http://youtu.be/FMNkPCtkM80

[Mayhem]

I believe Rob Wilson made himself one of those. His was much better finished though.

[Sunset Machine]

Here's mine. Never mind the center hole, it was arbor mounted but I needed an adjustable one and so here it is.

[PixMan]

There's a big difference between a face mill and a shoulder mill. I know, it's semantics to some of you but a night & day difference to someone like me.

I have both. A lead angle face mill can mill flat surfaces but cannot mill to a square shoulder. A 90º shoulder mill can also mill flat surfaces, but can also mill shoulders.

And a fly cutter can be either depending upon how the cutting edge is presented to the workpiece. Do you need one when you have a V555? No, but they can be nice to have when you need one consistent finish across a wide surface. Also, when a fly cutter is used, the larger the sweep is the more variation you get in actual surface finish value. For instance if you have a 5" cutting diameter of the cutter going across a 4.75" wide surface, the measured surface finish at the edges will be 1/2 or less of the reading you would get at the center of the work. And the edges would be "shinier."

The same effect happens with smaller diameter face and shoulder mills, but it seems to be less noticeable. I really noticed it when I was fly-cutting the 6" wide aluminum for my dad's burial urn. The edges polished up with little effort, the center of the plates took 10x longer.



There you have from left to right a face mill, a shoulder mill, a face mill and a face mill.

[Micktoon]

Nice cutters Pixman, I have noticed the effect you mention with the edges compared to the centre , can the effect be lessened with spindle speed or feed rates ? Does anyone know.
  Cheers Mick