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Discussion Starter · #1 ·
Compliments of (stolen from) Michael Bateman (Bateman Racing) and the f-160 group.
ENJOY!..... Steve

For all those who are trying to deal with broken off or stuck studs
etc for the first time - Welcome to vintage wrenching! :)

Learning to deal with broken off fasteners is going to be a lifelong
quest from this point forward, and one of the most important skill
sets you can cultivate.
(notice high-falutin' words used - vintage is "high class...") You
will eventually develop a whole quiver of skills to use in various
different situations.

Here's a few tips -

First - don't break it off. That's easier said than done, but you
should develop a feel for when something doesn't want to give and
start working on alternate strategies before you break it - actually
before the metal even starts to yield as at that point you're in
disaster recovery mode.

Second - the answer is always "it depends." There are multiple
strategies to try, depending on what you have available, your skill
set, the nature of the broken/stuck fastener, and what's already been
tried and failed. I'll give you a few here.

For merely broken off stuff that isn't stuck (usually the victim of
overtigntening) you can generally use a dremel with a cutoff disk to
make a slot in the end that you can drive with a screwdriver.

Heat (lots of it) is your friend. If the fastener is in aluminum
(virtually always the case for us) heat the heck out of the aluminum
surrounding the fastener. Like smokin' hot - 300+ degrees. If spit
doesn't sizzle it's not hot enough. For large sections this will
require more than your propane torch. This does several things,
including altering the nature of the corrosion causing the problem,
but also aluminum expands with heat at about double the rate of steel,
helping to loosen the aluminum's grip on the steel fastener. If
there's something left to grip this generally works best and should be
your first attempt.

Heat can be combined with other strategies - like using heat and a
screwdriver slot cut with a dremel can sometimes work.

Welders - if you have a welder and a fastener broken off flush, you
can plop an oversize nut over the end of the fastener and weld the nut
to the end of the broken of piece. Easiest with Mig or Tig, possible
with any welder. This creates lots of heat as well that helps. The
nut can then be used to turn the fastener. Sometimes it works,
sometimes it doesn't.

Easy outs - just don't. No really - don't. Especially in the little
bitty size fasteners we encounter (under 1/2" size) They're made of
harder metal than any drill, and will almost always just break off in
the piece you've drilled - making it impossible to go further forward.
Once you've gotten to the broken off easy-out stage, you're at the
point where you need either a friendly machinist with extra carbide
end mills that they don't mind ruining, or someone with and EDM
machine (Electrical Discharge Machining). Again - just don't.

Penetrating oils do sometimes help - and can be combined with
heating/cooling cycles to get the oil to really penetrate. The best
is Kroil made by Kano Laboratories. Kroil in a regular can, AeroKroil
in an aerosol can.

Drilling. A whole skillset in itself. For our little fasteners this
is a difficult skill to master. You'll need high quality drill bits -
cobalt generally. Carbide bits are a bit too brittle, though if
you're doing the drilling in a drill press or milling machine carbide
is best. For freehand work stick to cobalt bits. You'll want
something to indicate "straight" - a small block with lines or holes
drilled straight so you don't have to guess. Use a center punch, then
work hard to get the hole centered. It's difficult to tell where
centered is due to the helical nature of the threads on the fastener.
Use a left hand drill bit if you can find one.

Then stick out your tongue, hold your breath or whatever you need to
do to keep drilling straight.

Start with a drill significantly smaller than the fastener, and use
cutting oil. Don't break off the bit in the fastener...

Once you've got a nice straight hole drilled through you might get
lucky and be able to twist it back out. sometimes when using a left
hand bit the fastner will come out on the drill bit once you get most
of the way through.

Generally though, you'll be continuing up through the sizes of bits
until you're just left with the threads. At that point if you're both
good and lucky, you might be able to pick the remaining threads out of
the aluminum and clean up the hole with a tap.

But usually at that point you'll end up using a helicoil kit. They
come with the correct size drill for the helicoil as well as the right
size tap and the insertion tool.

Machine tools. If you've made it this far and are still in disaster
recovery mode - you're stuck with taking the piece to your friendly
machinist and begging for mercy. This often requires extreme
disassembly of what you're working on (usually the engine). They'll
know what to do, but will need things disassembled to the point that
they can fit it on a milling machine and properly fasten it down. It
might be expensive. It will always be a massive hassle.

At this point you'll be fully convinced of the importance of the
initial advice -




3,926 Posts
Id like to add a tip here that has always helped me and my father around the farm on large and small fasteners alike.. It's worked on several motorcycles over the years for me as well..

The part where he mentions..

"Welders - if you have a welder and a fastener broken off flush, you
can plop an oversize nut over the end of the fastener and weld the nut
to the end of the broken of piece. Easiest with Mig or Tig, possible
with any welder. This creates lots of heat as well that helps. The
nut can then be used to turn the fastener. Sometimes it works,
sometimes it doesn't."

It really helps to use an old rusty steel nut with NO galvanized-zinc/chrome plating left on it. As for the zinc-galvanized coating, you can burn it off, before welding on it. The zinc plating seems to add an impurity to the welding process that seems to make it break the weld loose from the bolt/stud a LOT easier.. Once I weld the nut onto/over the broken bolt or stud I like to rap on the nut pretty heavily with a traditional steel hammer. It seems to apply a "shock" force to the threads. That, when combined with the heat usually takes care of our problems..

GB :mrgreen:

Premium Member
2,386 Posts
Some good tips in there. I've got a good tig welder but never thought to try putting a nut over the top of flush stud and tying to weld it on. That might have worked in my case.

73 Posts
I've found an excellent extractor set, made by Alden tools. They come in several sizes, all the way down to one that works on 4/40 hardware. One end has a left hand drill, some cases the left twist will pull a screw out, if not , after you drill it , flip the bit over, and it has a fine pitch, fluted extractor on it. They work VERY well.

9,797 Posts
Sparbolt: you need to amend your link with a 'p' in corporation.
Thanks for your input.

9,797 Posts
Thanx, Richard. And Merry Christmas to you and yours.
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