Tap removal

[Saracen]

Further to my recent RFQ on removal of a tap from a machined aluminium part, I received a couple of PMs suggesting using a chemical etchant to remove the broken tap.

Yesterday, I managed to devote some time to the problem.

This was the part, with an M3 tap stuck in the middle hole. It appears this was to have been the last operation on this piece, as is always the way:



You can just see the pointy end of the tap poking through at the end of the slot:



With the aid of a £2.50 aluminium pan from Asda and a solution of BTR-10 Tap Removal Powder, I set it simmering yesterday afternoon.



Once it was up to temp, you could clearly see the bubbles emanating from the reaction with the tap:



It took several hours, but then I did keep removing to check on progress. One worrying factor was that parts of the aluminium also appeared to be fizzling but it doesn't appear to have affected the part.

Once washed and dried, I was able to complete the thread in the hole. The end is a bit bashed around from previous attempts to drive the tap out, but I think it will be perfectly serviceable.

Adrian.