Bugger, broken drill bit...

Possibly with a tap extractor? See McMaster-Carr, not that they make any
claims for using them with drill bits. ~$12 for the two-finger style.

For a drill bit, possibly kludgeable with two hunks of spring wire that
will fit in the flutes and an adjustable wrench or vise-grip clamped
close.

Turn the part upside down and apply heat - the hole should expand more
than the drill bit does.

There may also be a chemical approach.

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

there is.  Searching my own archives, but it was posted here.

Something akin to "Boiling out broken taps".

Go wayback.

LLoyd

Lloyd E. Sponenburgh wrote:

ISTR something about using alum as a means to dissolve steel without
affecting aluminum . Of course I may be wrong , and it would be neither the
first nor the last time .
--
Snag
Learning keeps
you young !

Snag wrote:

That's what I've found searching around as well. Of course no regular
stores actually carry Alum any more, so I had to order some. I also
ordered up some Lye for the eventually anodizing of the part since
nobody carries that any more either *grumble*.

Canning/spice section, grocery store...wally claims to have it at all
the nearby "supercenters", though the closest which is not a "super"
does not have it. Drugstores may be another source.

One local grocery chain with online access says not, another says yes.

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

Alum, saturated solution in water. use it hot (near boiling). immerse the
part. I have tried building dams around it and it is always a big PITA.
With a hole that small and that deep, you will want to occasionally poke
fresh solution down in the hole with a piece of wire.


Paul K. Dickman

Alum, saturated solution in water. use it hot (near boiling). immerse the
part. I have tried building dams around it and it is always a big PITA.
With a hole that small and that deep, you will want to occasionally poke
fresh solution down in the hole with a piece of wire.


Paul K. Dickman

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

[reply]

How long does this take to work, Paul? I just mean order of magnitude or
so -- hours, days, or what?

--
Ed Huntress

Ed Huntress wrote:

I'm hoping for such a small bit it's a modest number of hours with
periodic flushing of the hole.

#70 drill bit in a 16g watch plate will take about 10min.
Busted 1/4 20 tap in a through hole, maybe an hour or so until it is loose
enough to wiggle out.
His job is probably have to sit for hours. He might have to take it off the
hotplate at night and start back in the morning.
Because it is such a small, deep hole, the tiny amount of solution in
contact with the drill bit will get depleted right away.

Paul K. Dickman

=3D=3D=3D=3D=3D=3D=3D=3D=3D

Seems like some sort of agitator would be a big help with this.

Chris, a LDS member should know - almost better than anyone else - about
"putting up".  Alum is an essential canning salt.  They won't outlaw it.  
Heck! They don't even understand it!

Lloyd

#70 drill bit in a 16g watch plate will take about 10min.
Busted 1/4 20 tap in a through hole, maybe an hour or so until it is loose
enough to wiggle out.
His job is probably have to sit for hours. He might have to take it off the
hotplate at night and start back in the morning.
Because it is such a small, deep hole, the tiny amount of solution in
contact with the drill bit will get depleted right away.

Paul K. Dickman

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

That's quicker than I would have suspected. 'Pretty slick.

--
Ed Huntress

Well, part of that would come from the fact that you are not trying to
(or needing to) dissolve the whole thing - just enough to get it free.

If you have one skinny enough, (or a diabetic friend ;-) a glue
applicator syringe might help get the solution in where it will do some
good.

Another solution (non chemical) which is a tittle trickier in aluminum,
but could work given some bit is projecting, is to put a nut over what
projects and weld (or perhaps braze, with steel in aluminum) it to the
bit. More typically seen as welding with snapped off bolts or studs
(where the heat of welding freeing up the rusted threads is often as
much use as the nut to grab onto), but same basic idea...attach
something you can grab onto and twist.

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

Ecnerwal wrote:

I have plenty of syringes w/ 1/2" 31ga needles (allergy shots),
presuming the plastic syringe would stand up to the hot solution long
enough to do something. The problem is the AL chips packed along the
flutes which make it hard to get the needle in there, but hopefully they
would loosen as some HSS bit gets eaten away.


I don't see welding working on a 3/32" bit, and particularly not
damaging the 7075AL the bit is in.

LIAR! <G>

Lloyd

I get Red Devil brand lye down at the hardware store. In with the drain
cleaners.
You don't find alum at the stores anymore because almost no one makes
pickles..
The few that do, lean to quick process pickles and lime is better for those.

Paul K. Dickman

On 11/16/2011 8:38 PM, Paul K. Dickman wrote:

I source alum from my local taxidermist.

MikeB

--
Email is valid but not checked often

Paul K. Dickman wrote:

Not anymore you don't.  Unless your hardware store has some REALLY old
stock.  Red Devil lye hasn't been made for years (2005?).  The word was
that its use to make meth was behind its demise.

Bob