On Feb 21, 6:21*pm, Mark Rand wrote:

I thought that the conventional wisdom was half the speed and twice the
feed-per-rev.

I usually go more like 1/4 to 1/3 of standard cutting RPM. Reamers
change size as they get dull which means your (precision) fit will
change agressively if you spin too fast. Chucking reamers are
essentially not resharpenable.

As for feed, at *least* twice, typically more like 4x or more.
Chucking reamers have a natural feed rate. Feed *hard*. The reamer
will naturally restrict the downward force when you're feeding too
hard and you'll feel this happen (not easy to do, BTW).

A lot of people run reamers incorrectly because they're used to
drilling. Reamers typically have six or more flutes, and are removing
very little material. When reamers are fed too lightly, they give
inconsistant results.

Low RPM, push as hard as the reamer will allow. If your hole ends up
too big, use a stone to *slightly* dull the flutes in order to control
the hole size/fit. *Always* make a test hole if the fit is important,
always use cutting oil, and never run the reamer in reverse.

Regards,

Robin