Cracked Set Screw

[Bob La Londe]

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.

[Carl Ijames]

"Bob La Londe" wrote in message news:pdn4ht$tbh$1...@gioia.aioe.org...

=======================================================

Go to www.mcmaster.com and put 2892 in the search box to see that catalog
page. They have tapered hex keys that you drive into a stripped head and
then turn out with a wrench. I've used the M5 size at least a dozen times
(although a Torx T20 does that job well and is usually handier) with
success. They have ones for socket cap screws and ones for socket set
screws, not sure what the difference is, maybe the length of the taper.
Anyway, maybe it would expand the screw against the threads and grip well
enough to turn it out without galling the threads? If you have a
sacrificial hex key that is a size too large you could grind your own taper
and try that (and save the $12.50 :-)). With the crack you probably want a
pretty steep taper, anyway.

--
Regards,
Carl Ijames

[Bob La Londe]

I buy 1/8, 5/32, and 1/4 inch by the 100ct box because I package hex
keys with molds so the customer doesn't have to hunt one down to use the
mold. (clamping screws, slidebar retention, etc) This set screw just
happens to be 7/32, so a little work on a 1/4" on the belt sander to
make my own tapered key might just do the trick. Thanks. Even if it
doesn't do the trick its a great idea.

[Terry Coombs]

  Any chance you can crazy glue a wrench in the screw ? Tried a lefty
drill bit yet ?

--
Snag
Ain't no dollar sign on
peace of mind - Zac Brown

[BobH]

Any friends have an EDM machine?

BobH

[Jim Wilkins]

"Bob La Londe" <no...@none.com99> wrote in message
news:pdn4ht$tbh$1...@gioia.aioe.org...

Is the other end mushroomed?

[dca...@krl.org]

On Friday, May 18, 2018 at 3:14:35 PM UTC-4, Terry Coombs wrote:

>   Any chance you can crazy glue a wrench in the screw ? Tried a lefty
> drill bit yet ?
>
> --
> Snag
> Ain't no dollar sign on
> peace of mind - Zac Brown

If you are going to buy a left hand drill bit I would go for carbide. Set screws are pretty hard.

I have used a Harbor Freight little turbine ( mini air die grinder ) with dental bits to get out broken taps.

Might try a dremil tool and a diamond rotary file. The diamond rotary files are pretty cheap on Aliexpress.

[Robert Nichols]

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.

--
Bob Nichols AT comcast.net I am "RNichols42"

[Larry Jaques]

On Fri, 18 May 2018 14:14:34 -0500, Terry Coombs <snag...@msn.com>
wrote:

Or a Robertson or torx driver?

--
If we can ever make red tape nutritional, we can feed the world.
--Robert Schaeberle

[Gunner Asch]

On Fri, 18 May 2018 11:03:42 -0700, Bob La Londe <no...@none.com99>
wrote:

Drill it out in the milling machine.


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[Gunner Asch]

Excellent idea! Even if the screw doesnt turn..makes it much easier
to drill it out. Get it thin enough..then turn a bolt down into it
and it will collapse and push through.

[DoN. Nichols]

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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