I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

Thanks,

Pete C.

In article ,
"Pete C." wrote:

I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

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.

Ecnerwal fired this volley
in :

There may also be a chemical approach.

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:
Ecnerwal fired this
volley in
:

There may also be a chemical approach.

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

Something akin to "Boiling out broken taps".

Go wayback.

LLoyd

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:

Lloyd E. Sponenburgh wrote:
Ecnerwal fired this
volley in
:

There may also be a chemical approach.

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

Something akin to "Boiling out broken taps".

Go wayback.

LLoyd

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 !

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*.

In article ,
"Pete C." wrote:
That's what I've found searching around as well. Of course no regular
stores actually carry Alum any more

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.

"Pete C." wrote in message
.com...

Snag wrote:

Lloyd E. Sponenburgh wrote:
Ecnerwal fired this
volley in
:

There may also be a chemical approach.

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

Something akin to "Boiling out broken taps".

Go wayback.

LLoyd

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 !

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*.

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

Lye is supposed to be desired by some drug cookers. Meth,
was it?

So many things banned. Give it a few years, and they will
ban everything that actually works.

First they came for the lye. I didn't speak up, because I
wasn't a soap maker.
Then they came for the freon, and I didn't speak up because
I wasn't a HVAC man.
Then, they came for the alum, and I didn't speak up,
because I hadn't broken a drill bit.


--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Pete C." wrote in message
.com...

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*.

Pete C. wrote:
Snag wrote:
Lloyd E. Sponenburgh wrote:
Ecnerwal fired this
volley in
:

There may also be a chemical approach.
there is. Searching my own archives, but it was posted here.

Something akin to "Boiling out broken taps".

Go wayback.

LLoyd
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 !

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*.

Uh unless you live in the Artic every grocery store will have alum in
the spice rack. It is used in may pickling recipes.
If you live near any Amish stores you can buy it in bulk CHEAP.
It also works to dry up sores in your mouth.

Lye is also available in many of them.

--
Steve W.

On Nov 16, 1:52*pm, "Pete C." wrote:
I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

Thanks,

* * * * Pete C.

Lots of talk about virtually identical problem he
http://bbs.homeshopmachinist.net/arc...p/t-45761.html

I would add that a reasonable amount of foul language is called for.

On Nov 16, 8:52*am, "Pete C." wrote:
I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

Thanks,

* * * * Pete C.

Could you drill in from the other side and punch it out?
Karl

--If you can, weld something onto the end and work it out that way.
Here's a link to a photo of how I did this with a #10 tap:
http://www.flickr.com/photos/steambo...57624880666386

--
"Steamboat Ed" Haas : Steel, Stainless, Titanium:
Hacking the Trailing Edge! : Guaranteed Uncertified Welding!
www.nmpproducts.com
---Decks a-wash in a sea of words---

steamer wrote:

--If you can, weld something onto the end and work it out that way.
Here's a link to a photo of how I did this with a #10 tap:
http://www.flickr.com/photos/steambo...57624880666386

Good if in heat tolerant material, but unlikely to work without damaging
the 7075AL part in my case.

"Pete C." wrote in message
.com...

steamer wrote:

--If you can, weld something onto the
end and work it out that way.
Here's a link to a photo of how I did this with
a #10 tap:
http://www.flickr.com/photos/steambo...57624880666386

Good if in heat tolerant material, but unlikely
to work without damaging
the 7075AL part in my case.

7075 is _not_ that heat intolerant! I don't think
it will affect it one iota.
phil k.

Phil Kangas wrote:
7075 is _not_ that heat intolerant! I don't think
it will affect it one iota.
phil k.
--What he said; the drill is small enough and the aluminum massive
enough that it'll act like a heat sink. Just make sure the weld happens
fast. No need to weld to the end if you've got enough drill sticking out;
you can weld a lever to one side too.



--
"Steamboat Ed" Haas : Steel, Stainless, Titanium:
Hacking the Trailing Edge! : Guaranteed Uncertified Welding!
www.nmpproducts.com
---Decks a-wash in a sea of words---

steamer wrote:

Phil Kangas wrote:
7075 is _not_ that heat intolerant! I don't think
it will affect it one iota.
phil k.
--What he said; the drill is small enough and the aluminum massive
enough that it'll act like a heat sink. Just make sure the weld happens
fast. No need to weld to the end if you've got enough drill sticking out;
you can weld a lever to one side too.

I have only a tiny angled piece sticking out, and I don't want to affect
the heat treat on the part or cause any problems for the eventual
anodizing.

On Nov 16, 1:52*pm, "Pete C." wrote:
I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

Thanks,

* * * * Pete C.

Alum is easy to find, commonly sold in 4-5lb boxes/bags in garden
centers to acidify soil. (aluminum sulphate)

Avoid lye it will eat the aluminum.

On Thu, 17 Nov 2011 10:30:09 -0800 (PST), beecrofter
wrote:

On Nov 16, 1:52*pm, "Pete C." wrote:
I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

Thanks,

* * * * Pete C.

Alum is easy to find, commonly sold in 4-5lb boxes/bags in garden
centers to acidify soil. (aluminum sulphate)

Avoid lye it will eat the aluminum.

!!! I learned something. I can get it by the ton at the Co-op. Make a
saturated solution in a bucket and let the part soak. Bet if you used
a metal bucket and a hotplate, the chemical reaction would go real
fast.

Karl

"Karl Townsend" wrote in message
...
On Thu, 17 Nov 2011 10:30:09 -0800 (PST), beecrofter
wrote:

On Nov 16, 1:52 pm, "Pete C." wrote:
I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

Thanks,

Pete C.

Alum is easy to find, commonly sold in 4-5lb boxes/bags in garden
centers to acidify soil. (aluminum sulphate)

Avoid lye it will eat the aluminum.

!!! I learned something. I can get it by the ton at the Co-op. Make a
saturated solution in a bucket and let the part soak. Bet if you used
a metal bucket and a hotplate, the chemical reaction would go real
fast.

Karl

Don't use a steel pan. It'll eat it up just like the drill bit.

Paul K. Dickman

On Nov 16, 1:52*pm, "Pete C." wrote:
I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

Thanks,

* * * * Pete C.

I have had some luck using a small high speed tool like Harbor
Freight item 47869 and dental drills. It is not too fast, and I
would not recommend it on any tap bigger than 3/32 ". The tap gets
hot and loses its hardness to some extent.

i have also kludged up a electric discharge machine using a drill
press to hold the electrode. It was pretty simple. An isolation
transformer to a voltage doubler. Then through a light bulb to a oil
filled capacitor and on to a finishing nail in a dowel in the drill
press. The light bulb acts as a resistor that increases in resistance
if there is a short. The distance is critical . We ( I did this for
and with a friend. ) set the stop on the drill press and could get a
very slight movement by leaning on the down feed. We used kerosene
and had the part immersed in it. Since the sparks all occurred in the
liquid below the surface we did not have any fires. I do not
recommend this unless you have a reasonable background in doing stuff
like this. Lots of ways to get shocked or cause a fire. This is also
not very fast. My friend had broken a tap off in a .45 slide. After
doing all the playing, he took the slide to a machine shop and had
them burn out the tap.


Dan

On 11/16/2011 12:52 PM, Pete C. wrote:

I have a 3/32" HSS bit broken off ~1" deep in a blind hole in a 7075 AL
part, only a tiny stub of the bit is sticking out. Suggestions on how to
remove it without damaging the part?

Thanks,

Pete C.


I would MIG weld a nut on the tiny bit of bit available. If looks is
critical, I happen to have some copper tape that I would put on the part
with the drill sticking through.