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Bill Schwab
 
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Default Face mill, flycutter, etc.

Harold,

Fly cutters offer a wonderful way to machine without expense. They may be
correspondingly slower than multi-toothed cutters, but there's an offset if
you choose to run brazed carbide tools, so your surface speed can be
increased considerably. You can often get a far superior finish with a
fly cutter than other types, depending on the circumstances at hand.
Bottom line: If you have no money issues, multiple toothed cutters are
great, assuming you have the power and rigidity at hand to justify them.
Otherwise, stick with fly cutters, which are easily sharpened by hand, and
can be tailored to your needs easily.


Fair enough. Besides, the import flycutters are cheap, and I really
should have one, so I will probably start there and splurge on a face
mill if the flycutter gives me the creeps. I remember cautions about
the relatively large area of blur that is in fact a serious injury
waiting to happen, and some mention of a guy named "Lefty". While I
suspect that particular "Lefty" was largely a mythical figure, I note
that myths are often based in truth if not fact.



Don't put off squaring the head of your mill with the table. It's like
painting over rust. Regardless of the size of the cutter, the amount of
error still exists, it's just that the indicator, the step in the cut, is
reduced. Same incidence of angle, though.

It's dead easy to determine how much shimming you need. Spin a DTI on the
table of the mill, mounted in the spindle in a drill chuck, so you have
something to grip. The indicator should be mounted such that it generates
a circle the same size as the mounting boss at the base of the column.
That will reveal not only where you must shim, but how much.


When you put it that way, it does sound easy. The holes appear to be at
about 4.5x9 inches on center. The 4.5 in gap (if that's really what it
is) just barely fits between the slots (on the table vs. "in" the
slots). Or should I use the outside dimensions of the flange? The
inside dimension seems most appropriate, but I'm not sure I want to
spend that much time under 700 lbs of metal that is dangling on a nylon
sling.

It sounds like I need to mount the DTI, use the fine feed to move
up/down, and rotate the indicator to decide which corner is highest, and
then decide what if anything to add at the other corners. Loosen the
bolts, use my hoist to partially lift the head/column, insert shims,
lower, tighten and check. Is that reasonable?

Should I use any particular torque when replacing the bolts, or just
give a reasonable yank on an appropriate wrench? Speaking of wrenches,
I have a 15/16 socket that might be oversized, and a 22 mm compound
wrench that doesn't quite fit. The bolts are listed as being 5/8, but I
have seen metric sized heads on imperial bolts Anybody know what
fits it? With 15/16 being slightly loose and 22 mm too small, I guess
23 mm would be ok.



Install the
appropriate amount of shim to establish a 0-0 reading in all positions. You
may have to use small strips @ 90 degree intervals to get it right. I
think you get the idea.


I think so, except for the 90 degrees part. I am thinking of splurging
on slotted SS shims, but will want to make at least a first measurement
to get an idea of how much material I will need. I suspect it's not
much, but might be surprised.

Thanks!

Bill