bolt/stud extraction, broken extractor extraction tools, tips, tricks, and advice

[SUNBURNTsnype]

Hey guys,

In my line of work, I frequently encounter the snapped off, broken off, russted or corroded fastener that I need to remove with as little collateral damage to the existing thread hole as possible. Often times, this involves drilling out and extracting, or completely drilling out and re-tapping, or over boring and installing a helicoil or thread insert, or sometimes even completely plugging, and drilling a brand new hole and drilling and tapping a new hole.

Anywas, on several occasions, the extractors we are using to remove the fasteners end up breaking or snapping off and become lodged deep in the hole I just drilled, and then I spend the next several hours and several drill bits trying to drill out the hardened steel or tungsten material of the broken off extractor, and sometimes further damage the threaded hole in the process.

Obviously, we try to prevent as much of all of this as possible, from heating the fasteners and using penetrating oil, to shocking them with hammers and punches, etc. etc. but sometimes, after years and years of salt water, corrosion, electrolysis, heat cycling, etc. there is just no easy way to prevent these situations (I work on ships built in the 60's and 70's FYI). So I was just looking to pick your guys' brains for any tips and tricks and special tools for when you old timers have run into these type 'oh sh*t' moments when something breaks or snaps off and now you spend 2 days trying to extract a bolt from an irreplaceable piece of machinery without damaging it. We have a magnetic base drill press and I frequently have to make steel bases or flanges that can be affixed to whatever i am drilling in order to stay perpendicular to the workpiece. SOmetimes its not feasible however. I have tried diamond drill bits, carbide drill bits, high speed steel bits, cobalt bits, endmill plunge bits, carbide burrs, etc.

What is the best type of bit and material for drilling through a tungsten extractor when it gets broken off inside of a stud or bolt?

What are the best extractors that wont snap and shear off when i put a little torque on them? WHat is the best penetrating oil to get into tight joints?

I am in the process of procuring a Mini-ductor for our shop, which should definitely help. Are there any other specialized tools I should look at?

Are there any chemicals or mixes for dissolving certain metals when dealing with 2 different types of metal such as a steel stud and brass or aluminum housing, etc?

Thank you in advance for any help and advice.

 

[marineengineer]

I also work on ships bees wax helps as a penetrant just warm the piece and let it draw into the threads. Im interested to see what others say though

 

[bobcatdan]

There is no good one way to removed broken bolts. I'm a firm believer in kroil for penetrating oil. When at all possible I weld a nut on the bolt. This is as close to no fail I have found. For one broken below the surface, might as well spin the wheel of extractors. I own a wide selection of extractors and I don't know of one working better then the other.

 

[-Brent-]

Working on 1930s cars I've found that my best option has been letting penetrant sit and reverse cutting drill bits.

I'd like to try the bee's wax, eventually, where I'm able to add heat to the area.

 

[Fretters]

What are the best extractors that wont snap and shear off when i put a little torque on them? WHat is the best penetrating oil to get into tight joints?

Personally, I don't use extractors but go with a left hand tap, (most of the time that in itself will start shifting the broken stud/bolt), and then a suitable bolt in the newly tapped hole if it's still stuck. Right hand obviously if it's a left hand thread.

Wicking wax is about the best penetrant I know of, as suggested above.

 

[SUNBURNTsnype]

Personally, I don't use extractors but go with a left hand tap, (most of the time that in itself will start shifting the broken stud/bolt), and then a suitable bolt in the newly tapped hole if it's still stuck. Right hand obviously if it's a left hand thread.

Wicking wax is about the best penetrant I know of, as suggested above.

that is a genius idea. I cant believe i never thought of that. thanks.

 

[SUNBURNTsnype]

Working on 1930s cars I've found that my best option has been letting penetrant sit and reverse cutting drill bits.

I'd like to try the bee's wax, eventually, where I'm able to add heat to the area.

yeah ive got a set of left hand drill bits. seems like the really stuck ones dont really spin out easily with these, though.

 

[SUNBURNTsnype]

I also work on ships bees wax helps as a penetrant just warm the piece and let it draw into the threads. Im interested to see what others say though

bees wax...ill have to give that a try. only thing is doing hot work onboard is so tedious to get approved. cant wait till we got our inductor machine---then we can just heat things up whenver we want!

thanks

 

[Stroked383]

I have bought many different extractors and found they all ****. Die grinder with a little carbide ball bit usually gets the broken extractors out. As you know broken stuff is no fun and I do a lot of broken off exhaust manifold bolts and studs. My go to tool is the Mig welder. Even if its a cast iron head, as long as it flush I can get it with the mig and a box of nuts. If its broken off down the hole then I drill and tap. Extracting ***** and I don't have the patience to be using easy outs..

 

[SUNBURNTsnype]

There is no good one way to removed broken bolts. I'm a firm believer in kroil for penetrating oil. When at all possible I weld a nut on the bolt. This is as close to no fail I have found. For one broken below the surface, might as well spin the wheel of extractors. I own a wide selection of extractors and I don't know of one working better then the other.

kroil--ok ill give that a whirl. "wheel of extractors" haha aint that the truth. just yesterday i spent 2 days trying to remove a bunch of stainless studs from a brass evaporator shell that all were so rusted they snapped off flush with the end with barely a twist. 2 came out easily with extractors...and the other 2, well take a guess what the 2 days were spent on ...extracting the extractors that broke off and didnt work. definitely spun the wheel on those.

 

[-Brent-]

yeah ive got a set of left hand drill bits. seems like the really stuck ones dont really spin out easily with these, though.

The "easy" outs scare me and I've gone over to bits. A friend broke one in a antique head where there was no replacement parts available and had to have it EDM'd out since it was a high dollar restoration. It ended up costing him significant money.

I'm looking forward to what some of the folks around here have to say.

I've read that freezing the bit with freon or liquid nitrogen and then striking it with a punch could be done, too. But I've never done it. It's likely to be frowned upon in a commercial application, as well.

 

[Farmall450]

I like my Williams Square Tapered Extractors, but yeah, like someone said, a welder is the best extractor known to man. That and lots of PB B'laster. I have yet to try the wax thing, I can't see it working in my mind but maybe that's just me...

I use our mini ductor a lot on exhaust bolts at school, it's great and safer/less of a PITA than a torch. We call it the death ray...

 

[DenisG]

Google "tap buster" or "metal disintegrator" or "portable EDM" (EDM=electric discharge machining). Here's one: http://www.portableedm.com/package/

They're expensive (~ $10k), but maybe your business can afford it.

 

[marineengineer]

wax is possible on board and simple im in the engine room where hot work is approved unless were doing cargo (tanker) so it usually works. Another thing ive done was on a steam ship as a cadet used wax directly on a bolt that was already hot from the steam going to a main turbine the bolts on the valve packing gland were rusted so we just put wax on the hot bolt to let it melt. to get an extractor out sometimes you can break it with a center punch. but either way i don't think there is a good way to get them out if they break

 

[Farmall450]

Oh yes, don't forget left handed drill bits, it's worth the try.

 

[GRX]

As a machinist I have removed far more than my share of broken bolts and extractors over the years. Many of which when I worked for CAT. When all else fails I cut them out with a small carbide burr in my pneumatic die grinder.

 

[Otter Creek]

This is my first post and I want to thank everyone for all the information I have found on here. I have been lurking for a while.

Everyone has provided some good ways to remove a broken bolt. I just want to add that if the bolt is in cast it is pretty easy to blow it out with a torch. Through the years I have seen others do it and I was a little reluctant to do it myself at first. But it really is not that hard. The smaller the bolt the easier. Use a small tip and turn up the oxygen. Cast is hard to cut so you should not hurt the threads. Occasionally you have to remove a little slag with a punch and run a thread chaser in it.

Blind holes are a little harder because the slag is coming back out at your tip.

 

[joecon]

when I brake a ezout I use a rotobroch it is like a small hole saw and will cut the bolt
around the ezout an lets you get a grip on it and work it lose.It will only cut a shallow
hole so sometimes you have to work it with a hammer and a punch.

 

[WVBrady]

Personally, I don't use extractors but go with a left hand tap, (most of the time that in itself will start shifting the broken stud/bolt), and then a suitable bolt in the newly tapped hole if it's still stuck. Right hand obviously if it's a left hand thread.

Wicking wax is about the best penetrant I know of, as suggested above.

Where is a good place to get the left hand taps and left hand bolts?

This seems better than the typical extractors for two reasons: firstly, the bolt would not be so brittle and thus likely to break and secondly, the bolt would not tend to expand the hole in the stuck bolt, wedging it in tighter.

Edit: I see that you are in Jolly Ol' England. Any suggestions on this side of the Atlantic?

 

[Dan Jacobs]

I've removed a lot of broken bolts in the past 35 years actually I like the challenge
I WILL NOT use an extractor they all ****
Weld on a nut or drill it out period

 

[Finky198]

Get a snap on or Irwin 25 piece multi spline extractor set and a 29pc left handed drill bits and you will have a larger range of sizes. then get your self a drill doctor and some different penetrating lubes and and a small torch set then you a have a decent extractor set

Add a set of taps / dies and or a rethreading kit + drill bits and then your setup to repair threads to


As people have stated before if you can weld a nut that's your best option it's not always possible but when it is works It works perfectly

 

[carterbeauford]

I have a broken 1/2" bolt holding a John Deere B engine block to the tractor's frame. the frame is 1/2" thick steel and the bolt is broken off flush with the block, recessed 1/2" in the hole in the frame. been trying to get it out for 2 weeks. sprayed with penetrating oil and heated with MAPP gas torch 4 times. drilled through bolt with 5/16 left hand bit and tried 5/16 spline extractor. won't budge even with a long 1/2" ratchet. I am afraid of breaking the extractor if I put an 18" breaker bar on it.

 

[Finky198]

Your stuck just drill lot and re tap it

 

[SUNBURNTsnype]

The "easy" outs scare me and I've gone over to bits. A friend broke one in a antique head where there was no replacement parts available and had to have it EDM'd out since it was a high dollar restoration. It ended up costing him significant money.

I'm looking forward to what some of the folks around here have to say.

I've read that freezing the bit with freon or liquid nitrogen and then striking it with a punch could be done, too. But I've never done it. It's likely to be frowned upon in a commercial application, as well.

Yeah Ive read about the EDM. Seems a little out of price for us and you'd have to be able to bring the workpiece to the EDM device, which isnt always an option when your dealing with machinery in a ship's engine room that is too large to easily remove.

I do like the freezing idea. I'll have to look into that.

 

[SUNBURNTsnype]

I have bought many different extractors and found they all ****. Die grinder with a little carbide ball bit usually gets the broken extractors out. As you know broken stuff is no fun and I do a lot of broken off exhaust manifold bolts and studs. My go to tool is the Mig welder. Even if its a cast iron head, as long as it flush I can get it with the mig and a box of nuts. If its broken off down the hole then I drill and tap. Extracting ***** and I don't have the patience to be using easy outs..

yeah ive had to resort to the carbide burr in a die grinder trick a few times. only problem in other applications was soetimes i couldnt get it to bite into the hard tungsten of the extractor because it was deep down in a blind hole and the carbide burr was just spinning against it instead of biting into it. I ended up having to use some really small drill bits in the mag base drill and drill a bunch of small holes in the remaining area of the bolt between the broken extractor and the edge of the hole all the way around the extractor and then used the carbide burr to "connect the dots" of the holes i just drilled. This relieved enough tension on the extractor that i was able to pick and pull it out in pieces.

and as for the welding a nut or bolt...yeah i agree that is a much more reliable method, but oftentimes the break is below the surface by a 1/16" or an 1/8" and in order to get the space gas free certified and the all the fire watches posted and the welder hauled down and set up...it usually takes a good half day to a day. And sometimes they wont even certify the space gas freee if there is too much oil and grease in the bilge or surrounding area.

 

[richfinn]

If possible Drill the pilot hole before you shear off the head of the bolt, it's loads easier.

Drill a hole through a broken off stud before you MIG a nut on top, the heat will penetrate better.

Be mega patient, it's quicker in the long run

 

[SUNBURNTsnype]

wax is possible on board and simple im in the engine room where hot work is approved unless were doing cargo (tanker) so it usually works. Another thing ive done was on a steam ship as a cadet used wax directly on a bolt that was already hot from the steam going to a main turbine the bolts on the valve packing gland were rusted so we just put wax on the hot bolt to let it melt. to get an extractor out sometimes you can break it with a center punch. but either way i don't think there is a good way to get them out if they break

yeah ive tried the "shatter" method as well, but half the time i end up lodging the snapped off part of the extractor deeper in the bolt or if the hole is in soft metal like brass or aluminum then the sometmimes the threads in the hole get damaged by my attempts to shatter the extractor driving the bolt/stud deeper in the hole. also you pretty much have to re-grind the center punch after every hit cause the tip keeps getting mushroomed.

 

[SUNBURNTsnype]

I've removed a lot of broken bolts in the past 35 years actually I like the challenge
I WILL NOT use an extractor they all ****
Weld on a nut or drill it out period

yeah im slowly starting to come to this realization. I think the few successes i have had with extractors has been far outweighed by the problems associated with them breaking.

Though there are times where there are flanges or piping or other intereferences where drilling is impossible or difficult. Am currently looking at procuring a 90 degree drill attachment for some of those hard to reach places.

I have also started turning drill guides/bushes to help keep the bit straight and true in the hole.

Are there any pre-made or off the shelf drill guides you use?

Also, what do you use to help get your initial first pilot drill exactly centered? ive tried center punches it, but invarieably, by the time i work my drill bit size up to just under the bolt size, I am almost alwasys off center by a few 1/64".

 

[GRX]

Everyone has provided some good ways to remove a broken bolt. I just want to add that if the bolt is in cast it is pretty easy to blow it out with a torch. Through the years I have seen others do it and I was a little reluctant to do it myself at first. But it really is not that hard. The smaller the bolt the easier. Use a small tip and turn up the oxygen. Cast is hard to cut so you should not hurt the threads. Occasionally you have to remove a little slag with a punch and run a thread chaser in it.

Blind holes are a little harder because the slag is coming back out at your tip.

^^ very true. Cannot remember how many times I have blown broken bolt/studs from exhaust manifolds with a torch, most times without harming the threads at all. On blind holes I usually drill a small side hole for the molten metal to escape. After obtaining the customer's permission of course.

 

[SUNBURNTsnype]

when I brake a ezout I use a rotobroch it is like a small hole saw and will cut the bolt
around the ezout an lets you get a grip on it and work it lose.It will only cut a shallow
hole so sometimes you have to work it with a hammer and a punch.

thats a good idea! thanks!

 

[marineengineer]

to get the hole centered on a broken off bolt i have used a carbide burr, file or milling machine to flatten and smooth off the broken part then i have a set of transfer punches and try to find the best fit to make the punch as centered as possible

 

[-Brent-]

Yeah Ive read about the EDM. Seems a little out of price for us and you'd have to be able to bring the workpiece to the EDM device, which isnt always an option when your dealing with machinery in a ship's engine room that is too large to easily remove.

I do like the freezing idea. I'll have to look into that.

They do make a portable EDM (it's posted somewhere in this thread, I think) but they run 10k new.

 

[Fretters]

Finally remembered the name of something I've been meaning to try for yonks as a penetrating fluid. Oil of Wintergreen, Wintergreen oil or Wintergreen. I think it goes by all names. Supposedly a very good penetrant, akin to wicking wax into a joint for efficacy. Never got round to trying it as yet though, personally.

Regarding left hand taps, any commercial supplier of taps should have those. Bolts I've no idea over your way. You could always get someone with a lathe to knock you a few up.

...then i have a set of transfer punches and try to find the best fit to make the punch as centered as possible

Can't really get it much closer to centre than by using that method.

 

[kenburkholz]

If you are lucky enough to have a bolt break off in an accessible area, you can drill out the bolt with increasingly larger size drill bits, until the bolt is very thin. then you can use a caping chisel to roll the bolt material to the inside and remove with a pair of needle nose pliers. This has worked for me on parts that were irreplaceable, and truly saved a lot of grief. Ken.