[Newbie] Face Mill Vs Fly Cutter

To me it just cost
I can make a fly cutter and sharpen the tool bit
The face mill cost more for both the cutting head and tool bits
When I had shop I use face mills today I use a fly cutter and save the money for other things

Dave
 
True, there is more continuous torque required by a face mill if being operated at an efficient chip load and a diameter nominally larger than the width of cut being taken. It is also my contention that the noisier interrupted cut of a fly cutter is essentially harmless. It is just less efficient as it is cutting at less than 50% of its rotation. So basically, the mill is getting a break for around half a revolution. A face mill provides more uniform loading and much greater in^3/min metal removal efficiencies. Either tool, properly applied will not shorten the life of a mill beyond its designed life cycle. Either tool improperly applied can wreck a brand-new mill on the first day. I have no emotional attachment to either one, I reach for what I have that I think will work best in a given situation.
 
Sounds like a fly cutter is good to pick up first, then a face or shell mill if I find a project that needs a larger amount of material removal.
 
I wouldn't worry about your spindle bearings too much. I would not expect them to last 100,000 hours, but even 10,000 hours would be a considerable amount of hobby shop use.

If you plan on cutting hot rolled steel, you will likely need to use a very small diameter face mill or a roughing endmill to break through the mill scale. I could not get enough horsepower out of my PM30's 1.5HP motor with my 3" 45-degree Glacern. It will rip through aluminum just fine, however.
 
I've used a lot of fly cutters with HSS bits. But after getting my Tormach, I bought the Superfly. This uses carbide inserts for cutting. The inserts for aluminum are very sharp and require very little cutting force. This and the fact that I usually only cut 10-15 thou per pass, make it pretty light on the power and easy on the bearings. It also leaves a mirror finish. I really love it, though I use a bit more caution when using it. I have a 2" shell cutter (with inserts), but find that I use the fly cutter far more often.
 
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