On 2008-01-30, Rex wrote:
John Martin wrote:
On Jan 27, 9:15 pm, "DoN. Nichols" wrote:
Nope. For an Atlas, just slip it over the stud and tighten the
setscrews to close the angled clamps (which he also mentioned making) to
lock it in place. (BTW, I would suggest bronze or brass for the
clamp.)


The Atlas clamps are, I believe, steel - at least mine are. Brass or
bronze sound good at first blush, but I'd stay away from them for two
reasons.

One: the clamping pieces project out from the compound or milling base
until they bear against the dovetail. They are well supported in the
base, as they are (or should be) a good fit in the holes there, and
you want them pretty stiff before they contact the dovetail.

Yes.

Two, and more important: while you don't want the clamping pieces to
wear the dovetail appreciably, you also don't want them to mushroom at
all. If the contact areas deform, they won't retract into the base -
and you'll have quite a time getting the base off the dovetail.

A good bronze is almost as hard as mild steel, and a bevel
ground on the edge of the dovetail angle will keep any mushrooming from
becoming a problem.

Mine are, as I said, steel. They are ground to match the angle of the
dovetail, and appear to be hardened.

Soft steel. Make them from dowel, then anneal. You want them softer than
the stud they bear against.

Soft steel or a good hard bronze -- and bevel the edges so
mushrooming does not restrict removal. I agree that brass is too soft.

My only example of this is in an old Atlas/Craftsman 6x18, and
the lathe is old enough (and has been through enough owners) so I
would not consider anything which I might find to be authoritative. And
I don't *use* this machine anyway (and have not for a large number of
years. For most of my work, I use a 12x24" Clausing, and for certain
types of work an Emco Maier Compact-5/CNC (5" swing over bed), which is
particularly nice in that I can cut metric threads at just the flip of a
switch. :-)

Enjoy,
DoN.

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