According to David Anderson :
Jon Elson asked the right questions. The face mill worked fine on my
vertical milling machine. The trouble began when I moved the same workpiece
to my lathe and used a 1/2 inch dia Williams boring bar in a toolpost holder
to bore 1.500 inch dia x 3-inch deep, using a 3/16 HS steel bit (not
carbide). Both operations dry. I will try again with a freshly honed
cutting edge plus cutting fluid and maybe reduced SFM . Dave

That is also a lot of extension for a plain steel boring bar --
six times the diameter. You could possibly get away with that much
extension with a solid carbide bar (with HSS or carbide insert tooling),
but for a plain steel boring bar, I would suggest that you use a 1"
diameter boring bar for everything that you can use it for. (Perhaps
start the hole with a tailstock-mounted drill bit, then take it up to a
1" bit (if your tailstock will handle a 3 MT shanked drill bit), use the
smaller boring bar to get enough diameter to clear the chips on the 1"
diameter boring bar, and then switch to it for the remaining work,
including the finish cuts.

Good Luck,
DoN.

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