A Tapping Attachment for Small Taps

During my engineering apprenticeship and while working as a toolmaker spanning 40+ years I would imagine I must have tapped countless thousands of holes.

- Graham Meek

During that period, I count myself lucky in that I never suffered a broken tap at work. At home however that is a different matter. I remember the fi rst tap that I broke was a 6BA, I was 16 and had just started work. The job in question was a Stuart 10 V steam engine cylinder casting and I was tapping the cylinder cover retaining holes. The tap was coming through the cylinder fl ange and I was about to remove the tap, but wanted just one more thread, (big mistake). Below the fl ange there was a cast radius that blends the fl ange to the cylinder outer wall. The tapping drill had probably wandered a little as it met the radius and the tap was probably being forced to the one side, hence the breakage. Luckily for me the broken tap was removed on the Toolroom “Disintegrator”, what we used to call “Spark eroders” when they fi rst came out, as this was their primary role at that time.

I seemed not to suffer any more tap breakage calamities through the intervening years until I retired about 7 years ago. When in quick succession I manage to go through about one set of 10BA and two individual 8BA taps like they were going out of fashion. I then recounted the 6BA tap saga above, it is funny how these things stick in one’s mind. I was beginning to think that BA taps and I were “Jinxed”. Recalling the breakage instances, in every case I had been tapping freehand with no support, this was one of my problems. The other I was not to find out until some months later, when I was told I had been suffering some minor muscle spasms which were producing a hardly perceptible involuntary twitch in my arms.