Jim Wilkins wrote:

On Mar 23, 1:23 am, Don Foreman wrote:

....
Morse taper is fine for drilling, unacceptable for milling unless
there's a drawbar to hold the cutter firmly in place.


Let me slightly qualify that statement. My 50-year-old milling machine
has the almost identical Brown and Sharpe #7 taper. I bought quite a
few endmills with tanged (not threaded) B&S 7 shanks when Wholesale
Tool closed them out. If the spindle and arbor are very clean and the
endmill is tapped in rather firmly they do work well. I have used them
only for light finish cuts and fishmouthing pipe for welding, since
they are considerably larger than the largest endmills that fit my
collets.

I've had good results welding extra metal onto butchered Morse tangs
to make them pop out of the tailstock on my lathe. I think you could
weld on a nut and make a drawbar out of allthread, with two nuts
jammed together at the top so you can adjust the length, and be able
to remove the drawbar if the weld breaks.

Bottom line, tanged Morse tools aren't -completely- unacceptable if
you are careful and go slowly. They are something I have to put up
with due to the obsolete spindle taper.

jsw
Ah, yes, the Wholesale Tool closeouts! I got some of these too, in M2
shanks, and already had some from who-knows-where MANY years earlier (I
inherited a bunch from my dad). Yes, all I have without drawbar threads
are tanged. All mine appear quite ancient. While all I have are M2
shank, I've seen much larger versions.

A few have a right-hand cut and a left-hand helix, that would tend to
seat then tighter into the taper. Those with a right-hand helix have
only a very slight helix angle. A high angle right-hand helix with a
right-hand cut was probably a receipe for disaster. A number have
straight teeth with no helix. These look similar to reamers, but have
far more aggressive edges.

Such cutters were apparently used mostly in very early days, and
possibly only for cetain kinds of work. Obviously they worked if
properly seated, at least most of the time, maybe. There may even have
been some other locking mechanisms used at times (still are today).
Since then, drawbars have became largely universal. It's obvious that
there were problems with the simpler setup, and that a drawbar was the
easiest solution.

Dan Mitchell
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