REMOVING BROKEN STUDS AND BOLTS
Leave yourself plenty of time - don't rush yourself or
'Murphy' will decent
upon you. Soak the stud
broken off in the hole with penetrating oil (or
equal).
BASIC
BROKEN BOLT/STUD REMOVAL Part I
For hardened stud/bolts, a high-speed and titanium tipped
drill should do the job. For
stainless steel or other harder studs/bolts you will need cobalt drill bits.
The difference between high-speed and cobalt drills can be amazing.
If you are lucky to have access to the more expensive carbide drills,
they are probably the best.
When drilling, you can push down a little on the 1/8-inch drill bits, but not too hard or they’ll break. The thicker 3/16-inch and larger diameter drill bits can take more downward pressure to speed up the drilling process.
First, the best way to start drilling is to put a small
center punch hole right smack dab in the middle of the piece to be drilled, if
the stud/bolt has broken off
leaving a relatively flat surface. If the surface of the broken stud is NOT
flat, grind a flat area with a Dremel Tool that is at least 3/32" diameter.
Then start with a small 1/8" (+/-) drill bit and carefully drill
through the middle of the bolt as best as you possibly can until you are
completely through other end. Keep
the drill bit parallel to the stud to avoid hitting threads. Be careful to not
drill into the metal beyond the end of the broken stud such as the cylinder head
or frame.
As you drill, squirt in light penetrating oil. When the pilot hole has been drilled, increase the drill size
to 3/16" - continue to enlarge the hole some more watching the depth of
your drill. Try an easy out (broken thread extractor) on the broken stud. If it
still doesn't budge, squirt in more penetrating oil and drill the hole slightly
larger making sure not to drill into the hole threads.
With the hole enlarged, try a larger easy out.
If the easy-out flexes or “twists” without turning the broken bolt,
stop and drill a larger hole for a bigger easy-out.
Twisting the easy out too much will cause it to break in the hole.
If that happens, you have compounded your problem.
NOTE: To avoid
bottoming out (i.e., drilling through the bolt/stud into the engine block) you
can measure by looking at another identical stud or bolt.
If you want a cheap safety to avoid bottoming out, use a piece of dowel
on the drill to limit depth. but don't use it too early as you want to see
exactly what your doing and it helps to have someone at a right angle to your
line of sight to help align true.
If you are running into a lot of broken bolts and studs
that, try to find some left hand drill bits similar to those used in
screw machines. Many times the drill left hand turns will reverse stud out as it
relieves the stress of the stud or bolt core allowing it to loosen! They are out
there for sale, but you have to look for them.
Some
times you can 'unstick' a stuck bolt by over tightening slightly - that
releases the galling of the threads. In this case you might try using a
threading tap that is slightly larger than the pilot hole you've drilled
just to get a slight 'over tightening' pressure on it - then try the 'easy-out'
again
Easy-outs will work best after this, but easy-outs come
in several designs and the ole twisted sister style don't do that good of a job
if the stud is stubborn, in fact it can make it much worse, by spreading and
quite literally riveting the piece in solid. There is a square easy-out bit that
is a little bit better. When you’re ready to turn out the stud, apply a
little heat to area with a propane torch, just to warm up and expand the
metal some. Not too much heat though, please use discretion here.
You can keep drilling slightly larger 'pilot' holes until
you get close to
the inside diameter of the threaded hole. At times I've found a small punch
or pointed chisel and a SMALL ball peen hammer useful to 'roll' the
remaining thin exterior of the broken bolt out of the female threads in the
casting. This is hard to do if
there’s a lot of thread corrosion holding the bolt in place.
After you get the bolt/stud out, 'dig out' all the pieces of the drilled
out stud with tweezers, then use a tap to 'carefully' chase the threads in the
cylinder head. Use liberal amounts
of cutting oil on your tap. If your initial tightening (that caused the bolt to
break) didn't strip the threads in the hole you'll probably be able to reuse
the original size hole. If it’s stripped you'll have to drill and re-tap the
hole to accommodate a stud with an oversize base.
Then, if all this works and you got the bolt/stud out clean, then go and find some stainless steel replacements, not the soft 10L18 stuff that is so cheap to make into bolts and studs. Don't forget that aluminum likes the use of never seize too. Especially on your spark plugs! ! ! !
I saw some stuff on tapping, (you can use Crisco for
lube!), and a few other things, but that's another time, if I feel up to it and
you want to hear it!
cruiser vroc#2600 classic 1500
TECH TIP: one other thing that I recommend is to not seat
studs into bottom of hole with any torque. It is bad enough to fix when they
seize and shear without the added aggravation. I don't mind it at all when they
come out with nut. Gives me an excuse to re never seize them anyway and makes
for an easiest of fix!
cruiser
You have already gotten all sorts of good advice for
removing the
broken stud... the oil and heat thing will help. You might also consider a
left hand drill bit to just turn the stud out... depending on how it feels.
In any case, you can get an 8x30mm stud at Napa. If they ain’t got it, they
can order it. Stainless sounds sexy but when it gets snug in aluminum, it
will gall and you will have a hard time removing it, even with anti-seize
compound. Just get regular hardened steel. I use 30mm studs with double nuts
on the end (rather than the acorns). You can turn the inner nut against the
outer to easily remove the whole stud if you want. To tighten, you put the
new stud in, just tighten the top nut after starting both nuts on the stud.
Take your time... this is a frustrating deal but you can always just drill
the stud out using progressively bigger bits and then clean the threads with
an 8mm tap.
--
Wiredgeorge
BROKEN
EASY OUT!! Part I
A broken easy out is almost as bad as a broken tap. There are
a number of ways to look at this and without a specific application I will go
broadband! First, I'd stay calm and hope for access to at least a little bit of
it and some room to work, you didn't mention room!
A fine pointed center punch and some gentle but well
applied pecks in as many directions as can be applied can loosen it a bit at
times from its lodging, but they do have a tenacity for wedging in and spreading
the walls out on the stud. This is generally from drilling a bit too big or
close to one side of stud, but it happens.
If that doesn't work, then we need to check again how well
can we get to it. If ya had room to drill then you got room to drill again but a
standard drill probably won't work, but it might. Easy-outs are generally high
carbon not tool steel, so it’s not all that hard, and can be drilled but you
got to watch it. I'd go to a carbide drill if it is not a real small easy-out
and drill at it carefully, using the stud as a guide, but the carbide drill will
walk off if allowed to so it is imperative to make a good pock in the easy-out
with a punch and follow it. Still a pain in thy arse for sure! I saw a pro
welder once touch one with his tungsten and high freq. it for a moment and then
just pluck it out! Saw him do that on a tap once that had me seriously worried,
and he took it out with the frequency of his arc. I saw it start to move while
he soaked it! Not much heat but extreme high frequency! And yes I watched with a
shield. I've had to core out taps and pick the pieces. And to be honest it would
be easier than tackling an easy-out point in a tight spot. Of course in a bad
spot then you'd have to disassemble and go for the heavy guns. I would too but I
have access to a fully equipped Jobber machine shop with almost anything the
heart could desire. Only problem is the machinery is running all the time and
gov jobs are on the bottom of the priority list. I didn't want to bring up the
acid trick, because it don't work too well in conjunction with aluminum, tends
to eat at the lesser metal fastest, but we know that. Again, heat applied to the
core of the problem is often best if the application will allow! It will expand
the point and also oxidize some of the fine and take the temper out of the point
as well as stress relive the bite of the point and stud too. Some times the heat
of a very small oxy acet tip with an oxy flame will loosen things up nicely but
best in cast iron or steel, maybe alum but it would have to be watched close,
alum goes plastic at 1000 and melts at 1050 so room for error! I had something
else, I know, but just can't recall it now! Might come to me later, like about
2:30 am sound asleep ya know! I'm done now, how'd I do?
cruiser vroc#2600 classic 1500
BROKEN
EASY OUT!! Part II
DON'T shoot yourself in the head!!
You were asking how to get a broken easy-out, out?
YES... they can
be removed...then after you get it out, NEVER use one again! I have
been
removing broken bolts in *heads* and exhaust manifolds for over 20 years and
NEVER used an easy out! The best way I have found is to HEAT the
broken easy-out, (oxymoron), cherry red. That makes the E.O. lose its
strength and
it can then be drilled out.
The *best way* to remove a broken bolt in a recessed hole, is
to fill
the recess by welding the top of the exposed bolt/stud, then weld a large
washer to the "blob". After welding the washer, add a nut to the top
of the
washer and weld it also. Let it cool, and then heat the surrounding
area with
a torch. After the area around the broken part becomes hot, TIGHTEN the
welded nut slightly, and then back the nut out WITH the rest of the broken
parts.
If you are working with cast iron, you can watch it get
cherry red, if
you are working aluminum you have to be really careful.... so it doesn't melt
into a little puddle. :>}
(it doesn't turn red...ask me how I know!!)
Bob...aka.... JUDGE