On 2018-05-19, Robert Nichols wrote:
On 05/18/2018 01:03 PM, Bob La Londe wrote:

I was taking a bunch of tool holders out of service the other day,
and I couldn't get the set screw out of one in order to push the tool
out.* It felt like the set screw was rounded out, but the set screw
looks ok, and a long handle hex key seemed to feel ok in the hole.

This morning after firing up the shop and getting jobs cutting I took
a look at it, and the set screw is cracked right down the side.* When I
try to turn the screw the crack widens up and the wrench pops around
inside the hole.* Its not a big deal I guess.* These tool holders only
sell for around $50 used, but hey.* $50 is $50.

Any suggestions.* I have considered trying to tap in an oversized hex
key, but its right there.* I have a drawer full but I haven't found that
one that feels like it almost wants to fit.

Is there enough space to use a cutoff wheel in a Dremel tool to cut
off the part that's pressing on the toolbit? That would take the
pressure off and should allow the screw to come out easily.

That depends on what kind of tool holder is being discussed. I
was thinking about the end-mill holders which I use in NMTB-40 and
NMTB-30 size, and those have no exposed part of the setscrew between the
threaded hole and the tool being held, and the setscrew is specialized
-- a flat and a bevel just right to match the Weldon flat on the end
mills, based on shank size. The bevels serve to set the length of tool
extended beyond the holder. (This also makes it difficult to drill out
too, because the flat is about the minor diameter of the thread. I
guess that a solid carbide drill could drill through the setscrew and
into the shank of the endmill.

However, if it is a typical quick-change toolpost holder, there
is a length of setscrew exposed, depending on the size of the tool shank
vs the size of the slot in the holder. (My experience is with the BXA
size holders, FWIW -- a 5/8" square shank comes close to filling the
slot. Use a 1/2" shank, or smaller, and there is room for the cutoff
wheel, if the wheel diameter is large enough to reach. And operate on
the assumption that the tool is expendable, too, and you can cut deeper
to get the play you need.

Oh -- and the quick-change toolpost holders typically have four
setscrews, while most of the end mill holders have one custom setscrew,
though I have seen a few sizes which have two setscrews, and the mills
have two Weldon flats.

So -- what kind of tool holder are we talking about here? The
price is within the range of used holders for both types.

Good Luck,
DoN.

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