Walton broken tap extractor

I have been making some adaptors and managed to break a 7/16 UNC tap! I tried the usual tapping of the broken bit that was just poking out of the hole but all that did was chip bits of tap off, I was still left with about 8mm of tap in the hole.

I did a bit of a search on here but apart from trying alum or making a home brew spark eroder I drew a blank so went on to the web and discovered the Walton tap extractor. I have to admit I was a bit dubious abut this device, basically it has four fingers that push into the flutes of the tap, a collar slides down to the job and a tap wrench is fitted and the broken piece was simply screwed out, much to my relief!

I did get as much of the swarf out of the flutes as I could to get the fingers in as far as possible.

These things cost about £20 - £25 so won't break the bank and I thought they might be of interest to others.

Looks like a useful bit of kit Henry.

What range of tap sizes will it fit?

Jim

Spot on. Last tapped hole as usual. I'm going to regret this but I cannot remember the last time I broke a tap.

regards Martin

Jim, they are pretty specific to the size of thread due to the fingers fitting into the flutes and the need for the correct number of fingers. They have been around since 1908 so not a new thing but it certainly got me out of a scrape. Mine came from Zoro as I had a 20% discount code, their website shows the range.

Martin, yes famous last words indeed! I was hand tapping this one too, good quality tap with a suitably sized wrench but it bottomed out and ping. I'm sure I have broken one before but not for many years and probably much smaller than this one was.

I thought they would be thread specific so a bit pricy to buy some "just in case". I agree they would be invaluable if they can rescue a part with a broken tap stuck in the last hole.

Jim

How the tap was broken can make a difference to how easily it comes out, if it has bottomed out hard it can be difficult to shift, if it has snapped due to a bending force applied to the tap then it can come out more easily if it’s your lucky day.

Mike

I have had success on one occasion with a Walton; as with many things, it is important to follow the instructions!

What is the smallest tap size this will work with?

Smallest is 3mm I believe.

regards

Thank you

They seem to work about as much as an Easy-out, sometimes You win.

Thank you for showing it Henry, never seen one before.

Please can I have one in 10BA?

does look interesting, always good to get the tap out without damaging the thread/hole

An alternative is, of course, to attempt to drill the tap and I have just come across a reference to Sandvik "HARD-CUT" drills which are specially made for this purpose. Their point geometry is rather like the three-faced pyramid of the old-style Rawltool for masonry.

Apparently, "the extra negative geometry of the drill produces a high working temperature which anneals the tap".

I have managed to get one or two out using a long pointy diamond burr with an air die grinder. A Dremel tool would be suitable too, and the burr I used came with a set of bits for one of those. You work from one flute towards the centre until you have ground away enough that the rest cleans out. Takes a while but can save the job.

John

Just a thought on how the tap may have broken...

.... If you were not using some form of tap-guide in a bench-drill, or similar aid.

If you used the same set-up in the vice for the tapping as illustrating the extracting, the adaptor might have twisted slightly sideways, rotating about the very small contact areas, so suddenly throwing a side force on the tap.

I would suggest either using soft V- or channel- blocks (e.g. cut from thick plywood) between the work and vice-jaws; or clamping the work down to a solid surface - e.g. the bench or a piece of wood in the vice.

With similar annular objects, I've exploited the central hole. I've fitted the item to a bench-drill table-slot, or board with 10mm through-hole and held in the vice or G-clamped to the bench; using a stud, cross-bar and nuts (e.g. from the milling-machine clamp-set).

Another point I have found is work-height relative to own height - not much in my case. It feels to me that hand tap-wrench or die-holder handles above elbow-height make it harder to produce even, balanced forces on the tool.