Removing broken boiler fitting

[ianr]

I have. 3 1/2 gauge Juliet my late father built. When preparing it for a test steaming after it not having been used for a few years. I over tightened the boiler blow down cock while refitting it to the boiler. It has broken off inside the boss in the boiler. I’m now looking for the best way to remove it? Stud extractor?

Would be grateful for any advice. Don’t want to do more damage!

Thanks
Ian

[chris vine]

Hi Ian
Bad luck! If it was brass it was probably weakened with age and dezincification.
First put lots of penetrating oil on it. Wd40 at a pinch and leave it overnight .
Then maybe you can use an old Allen key tapped into the hole ? Extractors may expand the fitting and make it tighter.
Anyway, find something you can twist it with.
Then try turning back and forth, not trying to just unscrew it.
Also lots of tiny taps with a small hammer. The idea is just to shake it microscopically so that the penetrating oil works its way down the threads.
Try lots of different things but don’t force it too much in one go.
Good luck!!
Chris

[ianr]

Thanks Chris. Helpful advice. I’ll avoid stud extractors then. I put wd40 in it last night (that’s all I have). Left it overnight. Found one Allen key I thought was a tight fit. But after a couple of try’s it started just turning in the hole. Now it pushes right through to the back wall of the firebox. Next size up I have won’t go in enough to get a good grip. Can’t believe how tight it is in there. Thought once the tension was off the thread it should loosen up. Think I’m going to have to leave it and take it along to my ME club. Hopefully someone will have some ideas when they see it.

[John Baguley]

Do you have any of the star shaped Torx bits? They make good extractors for jobs like this. Just tap a suitable sized one into the hole in the broken fitting. It sounds as though it's the actual thread that's tight in the boiler bush rather than a case of just overtightening the fitting. If all else fails you may have to drill the broken stub out as large as you can until just a thin shell remains and then use a tap to remove the rest. Hopefully you can do it without damaging the bush.

John

[Nigel Bennett]

+1 for NOT using a stud extractor or "Easy-out" - the worst-named tool ever! One option might be to use a Torx bit. If you could get in with a small file to produce six little grooves to match the bit, you may get the Torx bit a snug enough fit to be able to remove the fitting. Other than that you could gradually open up the hole with increasing sized drills until you can pick out the "coil of thread" with a scriber. If you've got access to left-handed drills, use those.

[johan]

Might one of these be helpfull? www.amazon.com.be/-/en/QWORK-Tapered-Reamer-3mm-T-Handle/dp/B086HLMCKD/ref=asc_df_B086HLMCKD/?tag=begogshpadde-21&linkCode=df0&hvadid=633313067467&hvpos=&hvnetw=g&hvrand=2870942654058436147&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9040068&hvtargid=pla-1291478789892&psc=1&mcid=40bc6cd3e28e3cd9be04e72f47c36fe5&language=en_GB Do affiliation with the vendor, I just clicked on the first photo.

[ianr]

I think thats exactly what I’m being advised not to use! To be honest though I did try that exact set. But the length and taper of the threads meant the wide end caught the entrance of the bush before the narrow end could grip into the remains of the fitting. It’s looking like drilling it out and re-tapping is the only option. But I’ll try to get someone with greater skill the me to do it!

[jem]

I bit of heat might help!and wd40, then put it in the freezer for the night, and repeat. always with plenty of wd,

best of luck

Jem

[jo479]

I always use the tang of a file, select the right size take the handle off, knock it in and twist, never failed yet in 60 years.

[chris vine]

The file tang is a good idea!

Just don't force things and keep trying. If it moves even an atom, jog it back and forward rather than trying to unscrew it all in one go.

Good luck...
Chris.

[simon6200]

Grind a long 4 sided taper on an Allen key so that the edges are sharp, tap in and turn.

[ettingtonliam]

I would be wary of any method involvin drivin somethin into the broken off stub as it will always tend to expand it and make it even tihter.

I would favour carefully drillin in steps up to or just under the core diameter of the thread, then pickin out the remains. You cant drill off centre, the centre hole will keep you alined. A hand dill or battery drill will do the job just fine.

[JonL]

I'm glad its not just me that uses Torx bits this way! I don't often use them for their intended purpose.

[ianr]

Thanks everyone for all the great advice. All attempts with Allen keys, torx bits, file tangs etc have failed to get it to budge even the tiniest bit Didn’t think it was but must be a tapered thread to be in that tight. I think drilling out is the only option now. Hopefully will be able to either pick out the remains of the thread or re-tap it.

[johnd]

Sorry im late to the party, on holiday, but i have spent a lot of time removing fittings and studs etc when restoring pre war cars.
A common problem is that a previous rebuilder has assembled using whatever loctite was at hand, often the incorrect grade. This make disassembly very difficult.
I have a couple of hss lathe blanks, 1/8” & 1/4” ground with a very slight taper, edges left very sharp and attached to a tap wrench. I heat the item to hot then using hand pressure only insert the hss into the hole pushing on the tap wrench and turning, It works about 50% of the time.
And as you have found out, if all else fails all thats left is drill and pick, would suggest that you make a drill guide bush to help centre the drill.
Good luck.