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Broken drill bit in pewter


#1

I had some pewter cast from my master and I am drilling on them now.
I’ve broken off a few drill bits by now and I bet there is no hope
for this problem as the pewter would get eaten away in my sparex
too. Please advise.


#2

May I think out loud on this? I do not have a preconceived idea and
am just free flowing.

Two things, can a second drill be driven into the first one and then
both reversed? Can a second drill be gel glued onto the first and
reversed to drill back out?

Can a drill be introduced from the bottom and then used to back the
first one out?

sorry if I am way off base.
Teresa


#3

If it was a piece that I really needed, could not reproduce (make
another cast), or absolutely had to remove the broken drill bit, then
I would go to either a diamond drill or loose grit and do a root canal
on the broken bit. If I could create a hole deep enough in the broken
bit to insert a counter-clockwise threaded screw, I would try that
also. By the way, I am really paying attention to this thread, for I
have this problem on a slightly larger scale (sheared bolt for a front
wheel on a German make auto). Will E.


#4

Will the problem with your German made auto is somewhat different.
EZ-Outs, (left hand coarse thread tools), are not the best bet for
larger stud extraction. They enlarge the already stuck piece jambing
it even harder into place. The best bet is to drill, and this is
critical, the same size hole as if you were tapping it. Then use the
proper tap and chase the original threads if you can see them. This
is the best way I know but also the one requiring the most skill.
Good luck and have plenty of patience. Norman


#5

Will, for removing bolts there is a kit sold at hardware and auto
parts stores consisting of a set of tapered backward threaded taps. A
hole is drilled in the bolt and the bolt remover tap is twisted in
backwards. For removing tiny drill bits though it would be worthless.

Some years ago I solved much of my own problem of broken small bits.
A friend gave me a little drill press to be used with a handheld
Dremel tool. It provides a much steadier support than the hands for
the tool when used for drilling and I’ve never broken a bit yet using
it. Ans since I got my flex shaft I’ve no other use for the Dremel.
Geo.


#6

Broken Drill bit, Sheared Bolt When You are all hung up first drink a
cup of coffee or your favorite drink, then taking a old broken dental
pick, see if you can get any movement on the drill bit . A few drops
of diesel oil or one of my favorite all purpose oils for un sticking
things - K.R. Oil or Marvel Mystery Oil can expedite the removal of
the object. Another thing to try for soft metals is finding a piece of
metal tubing (Airplane Model shops are a great place to shop for odd
items) just big enough to slide the broken drill bit shank into. This
will allow the broken bit to become a guide. Then take a small saw
blade and make an X cut into the tubing end. A small hand operated
drill will be fast enough. If the metal is too hard for the tubing to
cut then use some silicia carbide grit (available in automotive parts
stores as valve grinding compound.) . And as for Balky German
Automobiles, give me a call off list Will E. I have been a Millwright
for nearly 30 Years and have learned to correct my many mistakes

Tex-eclectic AKA R L Powell


#7

This is probably the best post on this problem , even if it may seem
a little distructive. considering the small size drills involved which
are the kind that would break off.

The metals don’t even have to be soft, alittle doiamond compound
takes care of that. you might want more than 1 cross notch. It just
depends on what you have to cut out , you want to just surround the
totaly stuck object. Then just plug the hole or incorprate it in the
design. after the initial fool arround it is sometimes best to just
get drastic. Jesse


#8

First of all, let me state that I am a rank amateur at metal working
but I have had a thought re. your stuck drill bit that I haven’t seen
expressed on the forum.

Pewter is an alloy that melts at a low temperature (compared to silver
and gold).

What about using a large soldering iron or gun (probably 100 watt
rating) and touch the end to the exposed end of the broken drill bit.
This will in short order conduct heat down the bit into the portion
that is “captured” within the pewter, possibly softening the pewter
enough to twist the bit out with needlenose pliers.

See there, I told you I was an amateur at metal work. Now you must
surely “believe” I was truthful.

I hope you find a method that is sucessful.

Best regards
Ken Shields