27-03-2021, 11:58 AM
Good thought. I made up a guide bush out of 2" round aluminium when drilling the Seven blockĀ for helicoils. I couldĀ make a tube up to do the same thing for this tap, but the sealing surface is only a few mm across and surrounded by random bits of crankcase casting. The attraction of this solution is that I should be able to start the tap without drilling first and just eyeball the thread of the tap to keep things straight.