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Old 12-08-12, 01:25 AM   #11
Karragullengine
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Those welding rods sound interesting. I have never heard of that. Lately i have had a lot of luck getting broken bolts out simply by drilling it out and re tapping the hole. I find sometimes if you haven't centered the hole perfectly sometimes the bolts is softer than the hole and towards the end centres itself. Or stop drilling when one edge touches the side of the hole and can normally twist the remains out. In the past everything seemed to go wrong for me. Easy outs are useless, they simply snap when the tension builds. Then you are really buggered as they are very hard steel, but recently i have been told if you get a masonary drill bit and sharpen it really sharp will drill through a broken drill bit or easy out. I haven't tried yet but have a couple to do so i guess i will find out soon enough. Also something i have done a couple of times when the bolt snaps off flush with the hole put a nut on top and weld in the middle with a mig welder making sure you burn it in the the stud well at the beggining, then fill the nut up with weld and on the top make sure it is burnt in well to the nut. There is normally enough heat from the welding to transfer through the stud to lossen it.
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Old 12-08-12, 07:21 AM   #12
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If there is any of the stud exposed above the surface, by far the best way is to weld a nut on it, but don't do anything to it until it has cooled properly. The welding will normally break the rust and it will come out easily.
I would not recommend easyouts. Sometimes if the stud is below the surface I will drill out the hole with a smaller drill, make a fine chisel from a punch and carefully cut out the last of it.
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Old 12-08-12, 08:59 AM   #13
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Here we go, I found this (no idea if it works):

This site calls then Stud Extractor rods. (Although it looks like it is very much just welding a nut to the existing bit)

1 LB CONTAINER HOLE AC OR DC+
SIZE PART NO. PRICE EA DIA. AMPERAGE
1/16 SE116-1 $42.95 5/32-1/4" 25-35
3/32 SE332-1 $39.95 1/4-3/8" 30-90
1/8 SE18-1 $39.95 3/8-1/2" 75-120
5/32 SE532-1 $39.95 1/2"-UP 100-145
STUD EXTRACTOR
ELECTRODE FOR REMOVING
BROKEN BOLT STUBS OR TAPS
CHAMFER ROD
(GROOVE ROD)
DESCRIPTION:
The Stud Extractor was developed specifically
for the purpose of removing bolts, drills or
taps broken off below the surface of their root.
No special equipment is required for use of this
product. Extractions can be done in the shop or in
the field, anywhere there is access to a welding
machine. This product is coated with a unique
ceramic flux which protects existing threads during
the down hole buildup process. The complex alloy
structure of this electrode allows it to be used on
bolts and taps made of standard or hardened steels. Its deposited metal is stronger than most bolts
and will even gain toughness as you torque it during
the extraction process.
PROCEDURES
1. Select the electrode diameter and set machine to
corresponding amperage.
2. Select a nut with the same size hole as the hole in the
work piece and place it on the work piece hole to hole.
3. Insert Stud Extractor electrode through the nut and
strike the arc onto the center of the broken bolt or tap.
4. Maintain a short arc and build up carefully in the
center of the target piece straight up through the
middle of the hole allowing the ceramic slag to
surround the buildup and protect the existing threads.
5. Continue building up to the top of the nut but don't
weld the nut to the buildup.
6. Allow part to cool then remove the nut and protruding
portion of the slag.
7. Replace the nut around the buildup and weld the nut
to the buildup with the Stud Extractor rod being careful
not to weld the nut to the work piece.
8. Allow finished weld to cool to room temperature.
9. Lightly tap the nut to loosen slag then remove the
broken piece by turning the nut with an appropriate
wrench.
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Old 12-08-12, 09:15 AM   #14
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Invariably the bolt is sheared flush to or near the top, my method:-

assume its a 5/16 bolt
centre pop and drill with a 1/8" bit about 1/16" deep. Using a drill equal to the minor dia drill straight into the hole until it starts to cut the edges of the bolt - hopefully you will not cut into a thread line.
Examine the the edges of hole and check if there is any evidence of cutting thread line. If there is , using the 1/8" bit, drill at approx 45deg into the meat of the bolt for another 1/16", keep the pressure on and straighten the drill up.
Repeat the process with the minor dia drill and check if further correction is required.
Finally tap out with a No 3 to clear the thread, it should come out with a good spiral if you do repeated in and out for tap cleaning.
Tony.
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Old 12-08-12, 11:29 AM   #15
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Quote:
Originally Posted by sidevalve View Post
Nice idea but my problem has always been trying to get the drill to stay anywhere near central. All depends on the size of screw and if you can get a punch into the remains. Worth a try though.
The method I have used in the past to drill in the centre with a lot of luck involved was to use a short length of tubing which is a snug fit inside the exposed part of the thread (to protect the exposed thread) with a drill which is a snug fit inside the tube (the luck was in having tube and drill of the correct sizes. You only need to drill deep enough to create a centred recess in the end of the broken bolt, then use a small drill to create a pilot hole before the real action starts.
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Old 12-08-12, 12:14 PM   #16
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Quote:
Originally Posted by oldchadders View Post
The method I have used in the past to drill in the centre with a lot of luck involved was to use a short length of tubing which is a snug fit inside the exposed part of the thread (to protect the exposed thread) with a drill which is a snug fit inside the tube (the luck was in having tube and drill of the correct sizes. You only need to drill deep enough to create a centred recess in the end of the broken bolt, then use a small drill to create a pilot hole before the real action starts.
I like this little tip, will have to remember that in the future. Hopefully by then will have a lathe i can turn a small piece of steel to the right size. Paul
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Old 12-08-12, 07:14 PM   #17
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Quote:
Originally Posted by follytowers View Post
Here we go, I found this (no idea if it works):
Could be worth trying, but I have a feeling that it sounds much easier than it really is,..............

Hubert
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Old 12-08-12, 08:00 PM   #18
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Quote:
Originally Posted by Grendel View Post
Could be worth trying, but I have a feeling that it sounds much easier than it really is,..............
Hubert
Just what i was thinking Hubert Not cheap either at $40 a rod. People shouldn't discount easiouts. I've used them many times successfully. They may not remove rusted in bolts or bolts that have bottomed in a threaded hole & snapped off by exessive force but providing you use care they will remove most broken bolts. Masonary drills can be used to drill hardened steel. We used to use them in crankshaft manufacture when for whatever reason (usually error)oil holes were not drilled before the journals were hardened, we used them to break through the hardened surface. They do however need something to stop the drill wandering, we had a hardened guide. You cant center punch a hard steel! I dont think it would be successfull for removing a broken easiout as it would certainly run off centre into the softer steel around it. There's no substitute in my opinion for accurate drilling of the stubborn bolt with a small drill & opening it out gradually untill you can clear the thread manually then if you've overdone it drill & tap the next size up or use an insert.
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Old 12-08-12, 08:25 PM   #19
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Quote:
Originally Posted by novo View Post
Just what i was thinking Hubert Not cheap either at $40 a rod. People shouldn't discount easiouts. I've used them many times successfully. They may not remove rusted in bolts or bolts that have bottomed in a threaded hole & snapped off by exessive force but providing you use care they will remove most broken bolts. Masonary drills can be used to drill hardened steel. We used to use them in crankshaft manufacture when for whatever reason (usually error)oil holes were not drilled before the journals were hardened, we used them to break through the hardened surface. They do however need something to stop the drill wandering, we had a hardened guide. You cant center punch a hard steel! I dont think it would be successfull for removing a broken easiout as it would certainly run off centre into the softer steel around it. There's no substitute in my opinion for accurate drilling of the stubborn bolt with a small drill & opening it out gradually untill you can clear the thread manually then if you've overdone it drill & tap the next size up or use an insert.
That's exactly how I do it.
I do think that tapping to the next size is much stronger than using one of these helicoil jobs.

Cheers,

Hubert
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Old 12-08-12, 08:31 PM   #20
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Quote:
Originally Posted by Grendel View Post
That's exactly how I do it.
I do think that tapping to the next size is much stronger than using one of these helicoil jobs.

Cheers,

Hubert
Yes i agree, They are well accepted in industry but with size specific tooling they're very expensive for a one off job too.
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