Broken Tap Extractor

[ChrisHParticipant @chrish]

I came across a post the other day of someone who was good at breaking taps and having problems extracting them.  Been there too!

 

I can’t remember who he was or on what thread, but this is just to say that there are broken tap extractors on the market – Cromwell Tools do some, look at http://www.cromwelltools.co.uk – but whether they go small enough for this members problems I don’t know.  It will be food for thought nevertheless, if a small enough one is not available, in which direction to go to fabricate a suitable bespoke tool.

 

ChrisH 

[ChrisHParticipant @chrish]

[CirclipParticipant @circlip]

If it’s a CARBON steel one, a saturated solution of ALUM, (Look it up), but if HSS there are one or two circuits for simple spark erroders, although the “Experts” will probably advocate using a carbide drill.

 

  Regards  Ian.

[Phil AshmanParticipant @philashman88468]

I used the alum method to dissolve a broken tap in a boiler backhead bush, and I think it was HSS. Had to make a little container out of plasticene around the tap, so it only held a small amount of solution, and it took over a month to dissolve the tap! But it does leave the hole completely undamaged. It also helps if you can keep the solution hot.

Phil

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

Circlip is right with the dissolve method being effective,(you see we can agree on some things), but of course it depends on what the broken tap is stuck in.

I recently, well last year come to think of it, broke a M2 tap in some Aluminium, bu**ered if I was going to make a new part, if I didn’t have to, so,  I used some “cartridge case cleaner”. This is a dilute Nitric acid based solvent and ate the tap in about an hour, leaving a mucky black sludge and once washed a nice clean hole. If in doubt about dissolving the parent metal try a sample first, but C.C.C.should be OK in brass and copper, as well as Alloy. Iron and Steel would be a bit of a problem.

H&S rules may have changed since I bought mine at a ME exhibition, from he guys who sell metal blacking kits. If your paranoia says “mustn’t touch acid with a barge pole” don’t break taps!

chris stephens

PS the name on the bottle is Delway Technical Services with an 0151 phone numbe, I expect Goggle will find them if you are interested.

[AndyPParticipant @andyp13730]

Acid pickle will take out broken taps, and drills, so long as you have broken it in a non-ferrous part. If it’s in a cast iron Hunslet cylinder casting then you will just have to bodge a spark eroder like me  .

If you use the pickle method everything in it will be copper plated.

 

Cheers, Andy

[CirclipParticipant @circlip]

And acid will strip the Zinc out of brass.

 

  CAREFULL ChrisS, the FW’s are beckoning.

Edited By Circlip on 16/10/2009 16:58:51

[chris stephensParticipant @chrisstephens63393]

I could be wrong but the iron component will dissolve much quicker than the Zinc would leach out.  Long since forgotten my school boy chemistry.  Where’s Prof. Norman B. when you need him?

Don’t quite see what Focke Wulfs have to do with the issue? Men in white coats are more likely to be beckoning than WW2 aircraft. But fear not, I am always careful.

chris stephens

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