Extracting A Headless Bolt

Looking for any advice, guidance, and suggestions on how to remove a bolt whose head has been sheared-off.

To sum it up: the plunger rod of this hydrant fits inside a housing "cup," and a bolt comes in one side and squeezes the plunger rod between the bolt and the inside of the cup. When attempting to loosen the bolt and adjust the position of the rod inside the cup, the head of the bolt sheared off.

Does anyone know how I can successfully, cleanly remove the remains of this bolt? It's only accessible from one side: where the head used to be.

Any guidance would be appreciated. I'd rather not have to replace the entire hydrant, especially because of this kind of issue. Thank you very much...!

It's a common issue. There are left-handed drill bits and extractors designed for exactly this problem. They work. Any supply house catering to tradesmen will have them.

A lo-tek method is to carve a simple slot in the body of the bolt with drill and Dremel. And then tease it out with a stout mechanic's slot screwdriver that can take gentle taps with a hammer while torque is applied. Careful heating with a small propane torch may help loosen the body of the bolt.

Edit 3: Take note of the thread direction. A RH drill may do it.

I will second what Douglas has said.
I will also add:
Do something first to loosen the corrosion/seizing of the bolt. Heat and a penetrant will make things easier. The packing might be damaged by the heating, but that's probably something you are replacing anyhow.

Use a center punch to mark the center of the broken bolt to keep your drilling concentric to the bolt/hole. The extracting tools work best if they are centered, and if you goof and drill close to one side the thin bit can deform... and that can be counterproductive or even damage the internal threads.

Then, if it still won't move, you can keep drilling larger until you reach the root of the threads of the bolt, leaving only the spiral thread bit. Then you can pry and twist out with a pick and needle-nose pliers, and finish off by running the proper tap to clean up the threads. The brass rod that bolt is holding is replaceable, so if you drill into it, all is not lost!

I have used Kenneth and Douglas’ methods dozens of times in my repair business. I offer 2 refinements: dont slot the bolt unless it sticks out a bit; and be ready to buy a tap the size of the hole if you end up drilling the old bolt, so you can clean up the threads.

I think there's a set of screw extractors in the shop. I think the last toolbox on the left as enter the shop. I think the drawer is even labeled.

If the bolt sheared off, I'm also wondering to what degree the bolt tip is engaging with the plunger rod.  That cup piece can be detached from the rest of the assembly possibly (?) leaving it attached to the top end of the plunger rod.  Either shut off the water at the source or place a cap on the threads of the spiggot, then raise the plunger rod a bit with the handle to expose a bit more of the plunger rod from the pipe and packing nut.....no water will flow if you have prevented it from doing so as noted.  You may now be able to use heat, lubricants/derusting solvents, and other means along with pipe and vise-grip wrenches to remove the cup from the rod if it's not too tight.  If successful, this may make the bolt extraction process easier in a shop where tools and immobilization of the cup piece are more readily available.  Good luck!

Hi,   If heating with a torch use MAP gas in the yellow bottle instead of propane in the blue bottle, it's hotter.  If you have the finances buy an induction heater.  I always heat my bolts and nuts first before I break them loose.  30 seconds and the bolts are cherry red hot with the heater. Look it up on youtube to see how it works.  

The only option I can think of is to punch it and drill, heat it and then use an easy out extractor. Good luck.

This one requires a welder, or pulling the hydrant and taking it to a welder.

Find a thick flat washer where the hole is same diameter as what's left of the bolt.
Weld it to the remains of the bolt through the center hole in the washer
Weld a nut to the washer and use it to turn the whole assembly out.

as above suggested and weld on top of that a piece  scrap rod/bar/round---run a few beads of weld on that ---the heat will work its way down ---dab with a wax candle ---turn it back and forth ---need more heat --run another bead of weld on the scrap bar--of course much easier on a flat work bench

I deal with similar stuff all the time at work. There's not much that fire and violence can't fix. Heat it glowing-red hot with a torch, vibrate the living bejeezus out of it with a hammer or air-hammer (if available) right next to the threads and it'll likely back right out as long as the threads aren't boogered up. Sometimes heating it will loosen it to the point that it'll just be finger-tight and can be backed out with a pick, while it's still glowing. Same with the air-hammer method. Sometimes vibrating the crap out of it will cause it to back out on it's own. A combination of the two will work though, as long as the threads aren't trashed.

I very, very rarely have good luck with the drill-it-out method. The surface has to be flat to get a straight hole started. and if you're off center you're likely to mess up the threads in the hole and have to drill for bigger threads and use a helicoil kit (which isn't necessarily a bad thing, just more work and parts).

Heat is good. But I wonder how much vibration the casting can take without cracking.

After all the above just get your shovel out at the ready with a replacement hydrant. The head of the bolt twisted off because it was seized. So other than drilling it out and peeling the threaded remains out - and you'd better be pretty good to go right down the center of the broken fastener, best fortune to you. So many times someone doesn't go down the center of the broken bolt but goes to one side or goes crooked. Maybe even breaking the bit. Reread the first sentence. Oh yeah, and your water will be shut down or a geyser spouting if you fail.

Can you spot the center of a broken fastener. Most can't. Fewer can drill it out successfully.

I have a bolt doctor here, he uses a arc welder to weld a nut to the broken bolt inside the nut.
The welding rod is a special type which will not attach to cast iron, great for head studs.
The welding process heats the area and a ring spanner often then easily removes the bolt.
From an earlier post I put on my Hot Rod site,

"X-Tractalloy Product Code: XG168-mini
5 Sticks 2.5mm
X-Tractalloy is a special application welding electrode designed for extracting broken bolts, studs and taps from threaded holes.
•
Saves time and money — reduces downtime and labor by getting parts back into service quickly
•
Versatile — X-Tractalloy will also remove broken screw extractors, taps and broken drill bits
•
Strong — tensile strength exceeds that of Grades 2, 5, 8, 8.8 and 10.9 bolts and stainless steel
• IGNITOR TIP™ — for instant strike"

Jr Hill wrote:After all the above just get your shovel out at the ready with a replacement hydrant. The head of the bolt twisted off because it was seized. So other than drilling it out and peeling the threaded remains out - and you'd better be pretty good to go right down the center of the broken fastener, best fortune to you. So many times someone doesn't go down the center of the broken bolt but goes to one side or goes crooked. Maybe even breaking the bit. Reread the first sentence. Oh yeah, and your water will be shut down or a geyser spouting if you fail.

Can you spot the center of a broken fastener. Most can't. Fewer can drill it out successfully.

Well you may ultimately be right. But I think it's more interesting to try to repair things. Even if I fail I will have expanded my knowledge a little.

Well, I broke off a screw extractor in the hole I drilled in my first attempt. Gonna have a second look at it tomorrow.

I appreciate everyone's input and guidance on this. At least the discussion here can be helpful to others, so thanks to everyone who chipped-in with their insights.

It's the worst thing when that happens.

How did it go?  I've been following with interest.

It's not old enough or special enough to be reverse threaded, is it?  That was the worst bolt ever, but thankfully not normal.

Stephen B. Thomas wrote:Well, I broke off a screw extractor in the hole I drilled in my first attempt.

I'd say that with a broken screw extracter in the way, the welding techniques are the only options left. I can't see any other way to get the necessary grip on the bolt.
If you haven't already used a corrosion buster like PB Blaster, that's definitely worth doing as well.

How urgent is this fix? And what is your "gick index?"

ATF (automatic transmission fluid) has insane penetrating powers, given time. Mixed with acetone it is considered by antique car/equipment restoration guys to be far superior and cheaper than anything you can buy. This mix frees up antique engines that have been seized solid for decades.

David Wieland wrote:

Stephen B. Thomas wrote:Well, I broke off a screw extractor in the hole I drilled in my first attempt.

I'd say that with a broken screw extracter in the way, the welding techniques are the only options left. I can't see any other way to get the necessary grip on the bolt.  

It would be helpful to have a photo of the current situation.

If there is a protruding, embedded item, sometimes you can take a Dremel and carve in a solid purchase for Mr. 10 Inch Vise Grip, the chairman of the board.

Douglas Alpenstock wrote:

David Wieland wrote:

Stephen B. Thomas wrote:Well, I broke off a screw extractor in the hole I drilled in my first attempt.

I'd say that with a broken screw extracter in the way, the welding techniques are the only options left. I can't see any other way to get the necessary grip on the bolt.  

It would be helpful to have a photo of the current situation.

If there is a protruding, embedded item, sometimes you can take a Dremel and carve in a solid purchase for Mr. 10 Inch Vise Grip, the chairman of the board.

While we're waiting for a photo, I'll update my previous reply to say that if there's enough of the broken extractor protruding to use a Vise Grip then it's likely that the Dremel isn't really needed. In my experience, truly tightening a Vice Grip on a bolt digs into it enough for a solid grip. (That's a "power" tool that everyone should have.)

Thanks for your patience, everyone. Here's a photo of the hydrant's current state.



I think I have to do something about this, this week. I suspect I'll be suggesting we replace the hydrant.

Douglas Alpenstock wrote:

Jr Hill wrote:After all the above just get your shovel out at the ready with a replacement hydrant. The head of the bolt twisted off because it was seized. So other than drilling it out and peeling the threaded remains out - and you'd better be pretty good to go right down the center of the broken fastener, best fortune to you. So many times someone doesn't go down the center of the broken bolt but goes to one side or goes crooked. Maybe even breaking the bit. Reread the first sentence. Oh yeah, and your water will be shut down or a geyser spouting if you fail.

Can you spot the center of a broken fastener. Most can't. Fewer can drill it out successfully.

Well you may ultimately be right. But I think it's more interesting to try to repair things. Even if I fail I will have expanded my knowledge a little.

Oh, don't get me wrong - I repair EVERYTHING, even when I shouldn't. It's a joy in life for me to troubleshoot and successfully fix things I've never worked on before without a manual or wasting time on a darned YouTube video. I wish you the best.

Oh, and lastly, it's the perfect opportunity to justify another tool for the next time! (wink)

Stephen B. Thomas wrote:

I think I have to do something about this, this week. I suspect I'll be suggesting we replace the hydrant.

Can't recall if one can attach a PDF here but I will try or will make an image of the description.  We have a Merrill AnyFlow [ https://merrillmfg.com/ ] and among the replacement parts are the center rod (two rod pieces plus connecting nut) and foot valve that prevents water coming up through the pipe when handle is down (off position).  Before digging up and replacing the hydrant, you may want to check to see if these parts are available for your hydrant.  If so, you may just be able to unscrew the entire hydrant head which will allow you to pull up the entire rod and foot valve.....it's what you normally have to do to replace a bad/faulty foot valve.  *If* the machining of the hydrant is such that you can replace those parts and still have an operating hydrant, it would seem to be much less invasive than digging up and replacing the whole unit.  Depending the age of the hydrant, may be worth replacing the foot valve anyway if this option is chosen.  You might also be able to replace the entire hydrant head, but also may be able to just replace the siezed piece with the broken bolt.  Don't know if this may help...?

Edited to add.... Items G45, G50, and G55 on the diagram of the 1" pipe model on the right side of the image are the parts of interest.  Let me know if a photo image instead of PDF is needed.

The last thing one might try is a "tap burner" EDM, if anyone has such locally (or if one can be cobbled - I think I have plans around, somewhere, which used an arc welder as the power supply, a length of copper or brass tubing, I don't recall which, as the electrode, and an electric engraving pencil to jiggle the electrode toward and away from the work; kerosene was pumped through the tubing as dielectric fluid, to clear away the arc swarf, with some small pump [maybe a fish tank pump?] to circulate it).

I usually swear to myself that I'll really build one of these "this time", while I am trying to extract a broken exhaust stud or tap or whatever.  But, then more urgent tasks arise, and it gets shoved to the back burner once again.

The machinists in our shop at work would just use a carbide drill to drill out the screw extractor and screw, then pick out the remainder of the screw thread and chase the hole with a tap - all in a day's work, no sweat broken.  But, they're good, and I'm a hack.  Sometimes they do get foiled by broken off drill tips in deep holes - we often drill holes 0.040-0.090" in diameter up to 6" deep, sometimes crossing oil galleries in pistons, and/or the weld area between crown and skirt.  Every once in a while, a drill will jam and snap off.  Rarely, they can't extract the broken piece or pieces.  But pretty much everything else eventually yields to their efforts, it seems.  So, the assistance of a "real" machinist may also be helpful.

On edit:  I should point out that carbide tools generally require a rigid setup, i.e. a milling machine.  However, you may be able to re-grind a masonry drill to have metal cutting geometry on the brazed carbide edges.  I have managed this with a "Drill Doctor" to drill out a stuck wheel stud.  If you are good, you can free-hand the correct geometry, using a diamond wheel on a bench grinder.  The re-ground masonry drill will be more forgiving of less-than-rigid setups than a solid carbide drill would be, so a Cole drill (or the similar Little Giant brand), or a Port-a-mag drill may suffice - or even an old fashioned "chain drill" with a carpenter's brace.

For those unacquainted, here's an image of a "Yankee" brand chain drill.



Stanley bought North Brothers (of Yankee screwdriver fame), so some will be badged as Stanley.

Goodell Pratt and Millers Falls, among others, also made chain drills.  I have a Millers Falls, without the automatic feed mechanism.  I originally bought mine for the chuck that was on it, which can be inserted into the 1/2" pot chuck of my Millers Falls boring machine to permit use of more modern wood augers with 3 flats on the shank, rather than the special original 1/2" diameter shank augers with a flat for a square-headed set screw to bear against (similar to a Weldon shank).  But, the chain drill is an added bonus.  I do have a few of the 1/2" shank augers, but they aren't exactly common.

And a Cole drill:


The Little Giant brand was nearly identical to the Cole.  These are a little clumsy, but are a poor man's cordless Port-a-mag, and can be rigged up as a post drill, if necessary.  Definitely post-apocalyptic Mad Max grade.  With a re-ground masonry bit, you can drill through hardened steel, due to the extreme downpressure which can be exerted with the fine pitch feed screw.  Step drilling will be your friend, along with good layout practices (e.g. center punch, drift with a punch to correct or "set over" the first punch or to "ooch" the initial spot drill, etc.) to do reasonably accurate work.  There was also a matching vise made for the Cole drill, but I haven't laid hands on one, yet.

This link will take you to a somewhat more involved and sophisticated set of plans for an EDM machine than what I have hidden away in my stash of stuff:
https://dn790005.ca.archive.org/0/items/edmhowtobookbybenjaminfleming/EDM_How_to_Book_by_Benjamin_Fleming_text.pdf

For those who care...

John Weiland wrote:We have a Merrill AnyFlow [...]

As it turns out, this is a Woodford Y34, the old "Iowa" style. They do have a repair kit for this, but it's replacement parts. I'd need tools to remove this damaged screw before a replacement could be put in its place.

Thanks for sharing this, as it might help out someone with a similar problem and they style of hydrant head you shared.

Before I request that Paul approve an order for a replacement hydrant head, does anyone have experience in using a tap and die set to address these kinds of problems? Is it useful in this situation, or would it just be, "a chance to practice how to use a new tool"  ?

As far as this project is concerned, I think we're going with replacing the hydrant, then keeping the old hydrant and chipping away at it in the Woodshop. We can crank it into a vise there and maybe have a better chance at removing that screw.

...Time to go outside and chop some wood to help me feel better.

Again: thanks to everyone for your input on this uncommon challenge of mine.

Stephen B. Thomas wrote:Thanks for your patience, everyone. Here's a photo of the hydrant's current state.



I think I have to do something about this, this week. I suspect I'll be suggesting we replace the hydrant.

Using a 9/64 drill bit and a lot of patience with no small amount of good fortune you can drill though from the opposite side and using a 1/8" drift punch, tap the broken 'easy out' out of the screw. Your picture shows exactly what I mentioned in an earlier post about how hard it is to drill into the center of a broken screw. One of the things that happens with an easy-out is that as the tool feeds onto the broken screw it expands the screw making it even more impossible to start turning it. Screw extractors don't work so good on fasteners that are corroded into place. Wouldn't you agree?

At this point you can just plan on drilling the broken fastener out completely step by step and ending at 5/16 which you can then use your tap set to make the locking bolt 3/8-16. You'll need both a starting tap and a bottoming tap so the threads go deep enough. Or you can braze a nut onto the cast iron. What is left of the brass stem will depend on the amount of good fortune you have. You will have to 'build up the damaged section of the brass stem and dress it back to round again with a file and yet more patience without damaging the stem where the packing is or you have a forever spurting leak. Frankly you might just save the old hydrant for parts. This whole thing has gone past a 'grudge match' but I appreciate your tenacity.

You might guess that I am a Journeyman Machinist. And I have the tools. And I have done a lot of this kind of stuff but mainly for myself because nobody could justify the cost to pay for the work. Even for my own DIY, the good fortune thing is always big part of it.

Small - but significant - update. Two of our new Boots drilled through the other side of the metal "cup," tapped new screw threads in there, then added this big bolt. The hydrant is working now.