Often I need to extract broken bolts / screws and am thinking about
picking up some left handed drill bits. Usually I have to extract
broken steel bolts and screws from aluminum heads and manifolds. Most
often they are broke off clean and need to be drilled. When looking at
drill bits to purchase, I see they are made of HSS, Cobalt and
Titanium. What drill bit material is the best for staying sharp and
long lasting life?
Also, please comment on grabit and other extracting methods. What do
you think is the easiest way to remove a broken bolt?
Thanks for any advice
My favorite method is to center up an oversize hex nut (3/8
nut on a 1/4 bolt etc.) over
the broken remains, use a mig welder to weld the nut to the
Give it a shot of Kroil and unscrew. For small stuff drill
a hole in some sheet metal,
weld it to the screw, and weld a hex nut to the sheet metal.
Lots of Kroil, maybe run
it through a couple of heat/cool cycles, be patient. Works
90% + of the time.
I had intended to say in the initial post that welding wasnt an option
for me, but I failed to do so!!! I want to learn how to weld but that
is another subject. My main question is on the composition of the
drill bits. What material should I look for in the drill bits?
I use quality HSS bits because a) I don't need to do this very often and
b) HSS bits can be resharpened.
I haven't found an ez-out yet that works reliably. I usually end up
drilling out the bolt almost to the threads and busting the swarf out
with a bottom tap.
Last time I tried that I found that the busted bolts I had to remove
were unhardened, and of some alloy that my MIG welder wouldn't penetrate
it worth a damn! let that be a lesson to you, always use Grade 5!
Cobalt is a step up from regular HSS. Titanium is actually titanium
nitride, TiN, which is just a coating. It's the steel underneath that
Lots of ways to remove broken studs and screws without welding.
You're on the right track with the LH drills.
I've had fairly good luck with Easy-Outs. The trick is to use the
right size. Too small and it will snap. Too large and the remaining
screw will be thin enough that the Easy-Out will expand it.
Kroil, PB Blaster and the other penetrants are a must.
A hot alum solution will dissolve a steel screw without hurting the
aluminum head. Eventually. It works better on taps, because the
flutes allow it to work on the threads.
EDM is great if you can get the part to a shop that has the equipment.
"Nate Nagel" wrote: (clip) I haven't found an ez-out yet that works
reliably. I usually end up
The drill and tap method works for me, too. I HAVE found that Snap-on
extractors work well. They are not tapered. You drill with a drill that
they provide, and then drive in a splined shaft. Then slip on a nut with a
matching internal spline, that they also provide. Tapered easy-outs grip
only at the top of the drilled hole. Snap-ons grip all the way to the
Any tool for extraction will work but it's the setup that counts.
For the highest success rate it is beset to follow this procedure,
especially when removing a hard bolt from a softer surrounding
material like aluminum.
1. If broken bolt is above surface grab it with vise grips, use a
engraving tool to buzz it out, or turn it with a sharp punch.
2. If this doesn't work grind the surface perpendicular to the
3. With a magnifying glass if you need one, punch the
exact center of the bolt. Re-punch if you are off a bit.
4. Take a small drill and carefully without breaking the bit, drill
a pilot hole.
5. Step up to a larger drill that you feel you will not break
and adjust the drill location if necessary to make the
hole exactly in the center. Drill all the way through the
bolt if possible.
6. Now pick the correct size left hand drill, or drill/EZ out
If the bolt is bellow surface and uneven use steps three through
six. Pay great attention to step three, four and five.
Saw an ad on the TV the other night....Gator something. A set of
drill points on one end, and a matching easy out on the other. It was
used to drill a conical cavity in screw heads, and the matching spiral
easy out on the other end to remove the screwed up fastener.
Anyone know if these are worth a shit?
It takes the place of a punch. Orient the engraver so
that it pushes the perimeter, or whatever is available in a
counterclockwise direction. This will only work if the bolt is
not completely seized but just inaccessible.
"I had intended to say in the initial post that welding wasnt an option
for me...I want to learn how to weld..." *If* you have access to an oxy-acetylene torch with a cutting head, but
do not know how to weld, here is another handy-andy "hot wrench" trick.
It won't work in every situation, it can be quite messy, and gooey gobs
of red-hot sparks may fly in every direction. But sometimes it really
works well and may be the only way and/or last resort. In general, the
larger the diameter of the broken bolt, the better this works -- and not
just for broken bolts, but for broken or seized fasteners of all kinds.
Using a cutting torch head, adjust the oxygen and acetylene pressures as
you would to cut a piece of flat steel of roughly the same thickness, or
less, as the broken bolt's diameter. Heat the exposed area of the broken
bolt as rapidly as possible. Speed is of the essence here, or you may
end up welding the broken bolt to the surrounding material (which I have
done, thank you). The thing to keep in mind is to prevent the broken
bolt's surrounding material from approaching welding temperature. Once
this surrounding material begins to glow, it is time to remove the
torch, pause, and allow everything to cool down. Then, resume.
When the broken bolt end is red-hot, blast away with the oxygen. This
will vaporize the molten metal -- look out for red-hot molten metal
blowback upon your person. Repeat as needed until all of the broken bolt
has been vaporized. If the bolt was in a blind hole, you will have some
slag to clean out. If the bolt hole goes through, you can chase out the
larger bits of broken bolt by getting them red-hot also, and blasting
away with the cutting torch head's oxygen. In either case, *remember to
not allow the surrounding material to attain welding temperature*.
Finally, run a tap in and out and the bolt hole should be as good as
new. Well, almost as good as new...
Lots of helpful ways here to do many types of bolts and screws. I have
found that each one is different. And even two of the same types of, say,
bolts, the experience will be different.
But I have found a few things that apply straight across the board, and I
learned this at HKU.
First: Look at the situation. Don't be in a rush. Sometimes the best way
is the simplest. I have a lot of tools, and sometimes, I tend to
overengineer. And sometimes the simplest is the fastest. If it don't work,
you won't spend a lot of time on it before going to another strategy.
Second: You will probably get one chance. It will screw up or it will come
out. You'll fix it or you will ruin it. Make it a good shot.
Third: LET PENETRANTS WORK. I recently had a turnbuckle that was frozen.
I twisted the rod off in my hurry to get it off. Then I heated it with a
MAPP torch, applied some 3 in 1 oil and turned off the light. Next day, I
bought something like "Blaster" and hit it with some. About five minutes, I
wiggled the Vise Grips that was clamped to the stump, and it moved freely.
I don't think it was the Blaster, but letting the oil do its work and get
sucked in. So, if you use penetrants, let them soak long enough to do their
Last: Pay attention to your gut when it says, "It feels like if I twist
this any farther, it will snap." 99% of the time, my gut was right.
I have used one of those automatic punches chucked up to a drill press that
is not spinning. Easy down until you get it right and clamped. If I try by
hand, it seems to run off. If surface is slanted, you can also place shims
under the clamp to flatten out the angle so the hole happens pretty close to