We have all experienced screw heads breaking off on occasion and its
always quite a job to get the old one out and then trying to fix the
I've tried a couple of tpical screw extraction products such as ones
from Harbor Freight and HD, but they both sucked and actually broke
while trying to use them.
Occasionally I've seen on TV some magical extractors but we all know
what adviertizing is like...
For those of you you may have had success with some and would like to
recommend a good solution or two I would greatly appreciate hearing of
I figure, if one purchases something that actually works, it worth the
investment rather than buy junk only to throw it away and still have
the problem to solve.
Thanks IA -
Mileage always varies with screw extractors. The screw wouldn't come
out in the first place so extracting it is always iffy. The extractor
creates outward pressure as it attempts to embed in the screw. That
makes the problem worse.
Bets case is don't break it. Soak in wd40 or you favorite penatrating
oil for several days. If it will turn at all just work it back a
forth carefully. Let soak more.
Another option is to heat the surrounding metal. You really need an
oxy/act or mapp torch for this though. Propane is too slow.
Sometimes combine heat and soaking.
I often just drill with increasing sized bits until I start to expose
the threads. Then a tap will chase out the remaining metal. You need
to be really accurate. Helps to use a center puch and really small
bit to get exactly in the center. to start with.
Screw extraction can be tricky, depending on why the screw broke in the
first place. Sears sells a set of extractors that are kind of interesting,
they are like these:
http://www1.mscdirect.com/CGI/NNSRIT?PMCTLG &PMAKA027115&partnerURL=http://catalogs.shoplocal.com/mscdirect/index.aspx%6Fpagename=shopmain%50circularid 382%50storeid40626%50pagenumber02%50mode
They also sell smaller ones.
What I like about these over traditional easy outs is that you do not need
to drill as deep to get a bite with the extractor.
What size screw do you have and what is the material that it is broken off
in? If it is a steel screw broken off in aluminum or brass you can simmer
it in an alum solution and rust away the screw and leave the aluminum
About the time I had mastered getting the toothpaste back in the tube, then
I've also had my share of problems; they seem worse when I pick a size
that's too small. As mentioned, center punches and little drill bits
help in getting an accurate center. This helps being able to go
Never buy discount/tv screw extractors. I know the hype is often
overwhelmingly alluring, but it's all crap. Screw extraction is
tricky, exacting, and fraught with pitfalls. If you want to avoid
costly last-ditch methods, pay attention and spend the $$$ up front.
Good attitude!! ...and dead nuts on!
First, buy a quality screw extractor system. I'm talking quality
extractors made of high quality steel and requiring drilling a proper
hole first. There are two main types. One is a square shape with
little flutes at each corner. The other is a reverse spiral. Both
work equally well, but require a precise pre-drilled hole. Typically,
both have a square headed drive and require something like a T-shaped
tap handle to use properly. I realize this sounds costly, but not as
costly as failure.
These can be found at machinist tool supply outlets/shops. Again,
better to buy the good stuff, even if you have to do so online. You
might also check an automotive parts store. Auto mechanics are always
doing broken bolt removal and auto parts stores usually carry pretty
good quality screw removal tools. Try your local Napa store.
Second, make sure you have good drills and a center punch. Punch a
center. Take your time and be as accurate as you can. Drilling an
accurate and straight hole is the primary KEY to success. Use quality
high speed steel drills (HSS) to make the hole. Use a good cutting
fluid to make a clean hole. It can't hurt to soak the hole/screw with
all kinds of lubricants and bolt derusting/breaker solutions. Also,
make sure you drill the right sized hole for the screw/bolt size and
correct extractor size. Fudging is a sure-fire prelude to failure.
Finally, tap the extractor in with a small hammer to get a secure
grip, attach the handle, and begin the extraction. If you have
proceeded carefully, methodically, and accurately, you should meet
with success. If not, there's always EDM ....electrical discharge
machining (the costly last ditch option).
OH.... one fellow recommmended a reverse or left handed drill. Can't
hurt and sometimes it works, specially with smaller screws. If you
want to try it, again drill an straight accurate hole. It will either
work and back out the screw ...or not! If it doesn't remove the
screw, at least you will have a proper hole to proceed with the
Good luck! ;)
Couldn't agree more. One thing to add.
Invest in a good magnifying glass with a light to ensure that the
drill is centered. Use a SMALL drill to start with and maneuver it by
changing the drill angle until it IS centered. Then line up the drill
perpendicular. Use this small drill to make a pilot hole before going
to the finished size hole. I have used this method with #55 pilot
drills and a very steady hand. If done right the screw will always
come out unless it is welded in place.
More good advice from Tnom I forgot to add.
Tnom is rightfully reinforcing the accuracy dictum that you can't be
too careful. The smaller hole is what is commonly referred to as a
pilot hole and is used to guide a larger drill dilling a larger hole. You
haven't given the screw/bolt size you want to remove, so we are
shotgunning advice, here. Along those lines, and in the same vein of
accurate work, you might consider using a "center drill" to start the
initial hole work.
A center drill is commonly used by machinists to begin an accurate
hole for whatever type of drilling operation, be it a pilot hole or
the final drilling operation. They are short, sharp, and stiff, so
not what yer girlfriend ordered! ;) But, they are ACCURATE AND SHARP.
You surely can't go wrong by adding one to your tool set and process.
In fact, it would probably work better than a pilot drill. Always use
high speed drill motors (> 1500 RPM) or you will be adding a broken
center drill to the extraction process. They look like this:
(Amazon.com product link shortened)
Thanks for the advice and reminder, Tnmm. My geezer mind is a bit
I'd add that if it's physically possible w/o destroying the DUT, heat on
the surrounding part (not the bolt) is the one great leveling factor to
break the bond to aid in the removal once got the extractor ready to go...
Yet one more excellent trick to aid in extraction, dph.
OTOH, it matters not how careful you are. The heat will be
transferred to the bolt. Fortunately, physics dictate that the hole
will enlarge to a slightly greater ID than the bolt/screw's OD,
thereby facilitating easing of the overall interference fit of the
two. Just make sure you don't cook/bake any added screw/screw-hole
lubricants into an interfering paste/sludge. ;)
or if the bolt stub is protruding slightly, you can hold a cheap non-
dripless type candle to the bolt and let the wax wick into the
threads, heat it again, this time hold an ice cube against the bolt
stub or hit it with a can of spray duster. thermal shock can help if
nothing else works.
Yes, there's always that. Might jes shit and fall back in it, too!
Yes, can drill the damn thing out, even oversized, and intall an
insert in the now oversized hole. Won't go into induction welding
another bolt stub onto the broken bolt or other more esoteric
approaches. But, I think most folks responding here have been trying
to provide the easiest approach to gettin' the damn thing out with a
screw extractor, as per the OPs request.
Thanks anyway. ;)
Drilling to the root of the thread is only the last resort. In order
to have success with this method you must be even more accurate
with centering the drill. Then you have to cross your fingers that the
remaining bolt thread will come out cleanly and leave 100% of the
original surrounding steel.
Only if one has machining facilities. A complete drill out requires
much more accuracy than a partial hole for an extractor. As a
machinist myself, I still recommend an extractor as first choice. If
the OP was a machinist with access to a machine shop, I doubt he
would asking advice, here.
I use a Dremel tool with an abrasive/diamond bit for the hardest stuff.
There have been times when the little rotary tool comes in handy for
cutting slots in broken head studs on generators so I can use a
screwdriver to back them out. I've also used the Dremel tool to dig a
hole in a broken stud to get a screw extractor in it or to start a
hole for a drill bit. The tool can used to cut out a broken tap too.
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