face mills and Sherline?

[lagweezle]

I was about to ask why I don't see any face milling conversations, video, etc. with the Sherline, but I think I just came across the answer: it requires more power than the Sherline can deliver, or the depth of cut would be too shallow to make it's use worthwhile.

If I'm wrong on this, please enlighten/correct! Otherwise, this will at least be here next time someone starts wondering and goes searching.

 

[pstemari]

Sherline and Taig mills are far too small to be able to use a face mill. A fly cutter is the usual alternative, although you must take very shallow cuts with one, and using a braised carbide bit is a good idea.

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[markba633csi]

I would agree with pstemari however, I believe a sharp HSS tool would require less power and would cut easier on a tiny machine like that
mark

 

[mikey]

The Sherline inserted carbide fly cutter, part 7620, is essentially a single insert face mill capable of 0.020" deep cuts in steel and deeper on softer materials while leaving a very fine finish. It can also cut to a shoulder, something that many face mills cannot do. I've been using it for many years and it works very well for fly cutting and stock reduction. It is only 1-1/8" in diameter but it is more than suitable for use on the Sherline mill. In fact, I use one in an adapter on my RF-31 and it works just as well there, although it is capable of heavier cuts on the larger machine.

It turns out that this particular fly cutter produces a finish that is as good or better than a HSS tool will produce, largely because of the insert geometry but also because it runs at full speed, up near 2800 rpm.

 

[Aaron_W]

It is not just the really small mills like Sherline and Taig. Face mills don't seem to find much use even on the smaller knee mills that weigh hundreds of pounds.

 

[stioc]

Aren't the fly cutters supposed to be harder on the spindles since they're unbalanced as opposed to face mills?

 

[mikey]

I seriously doubt your spindle will notice any load put on it by a flycutter. A boring head presents more offset mass than a flycutter and spindles handle those fine, too. What spindles (and ways and gibs) do not like is chatter; that is a major cause of wear on a machine.

 

[lagweezle]

The Sherline fly cutters--both the "true" fly cutter, and the face mill-ish one--are pretty small diameter. Mass distribution is pretty tightly centered. I am guessing, but suspect that since we generally run muuuuch lower speeds than larger machines, the effect isn't as concerning, either.

I've seen at least one face mill-ish fly cutter made by the owner of the machine that is much wider; I imagine balancing those is a lot more important as the moment (I think that is the right word) is much larger as it's further from the center. I've not messed with physics stuff for quite some time, so this is from very fuzzy memory; if someone knows better, please do correct me!