In article ,
jim rozen wrote:
In article , Harold & Susan Vordos says...

Gotcha! And I do that when necessary, too, but it sort of supports those
that create the argument that you risk making scrap because you don't rely
on the tool to make the cut to size. It goes without saying that those
of us that work in the trade don't recognize the risk. :-)

Most folks understand that end mills flex.
When they do, the surfaces they cut are no longer
where you think they should be, based on a simple
'edge finder, and measure the (still) cutter'
calculation.

Agreed. Though the "slot drill" mentioned near the start of
this thread is not just *any* endmill -- it is a two-flute
center-cutting one, which does the best at cutting to width and with
minimal wander, because the sides of the slot are being cut only when
there is absolute minimum side force on the end mill.

The "slot drill" term is apparently more common in the UK than
in the USA -- but the function remains constant.

[ ... ]

Woodruff key cutters might cut a thou oversized or so,
depending on condition or size. A 1/8 inch end mill
could cut oversize, or offside, by ten thou or so.
Also small end mills will take a while to do a
keyway because they can't do it all in one bite.
Chip clearance becomes a big deal.

This is why I like keyseat cutters.

With all the mention of keyseat cutters in horizontal mills, I
don't see (yet) any mention of plain milling cutters for keyseats. They
work very nicely for the task, if you can accept the longer radius at
the end of the cut.

Enjoy,
DoN.
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