Something doesn't sound right....how thick is the plate? Won't the pilot be
unguided on the other side of the plate? Make a guide block and clamp on or
tack weld it. Or even a nut.

Tom,
This is just a hypothetical situation ... I was wondering if such a
thing existed as a piloted tap - just to get a tap started "dead on"
at the beginning of the process (by hand) where the pilot part of the
tap would keep you lined up until you were cutting the thread straight
and the pilot would indeed "work through the plate" but then you
wouldn't actually need it after the tap was started straight. I have
never seen such a tap, and didn't know if anyone had ever tried it or
not - my feeble grey matter just seemed to think it may be a good idea
in certain situations.
Ken.



Ken Sterling (Ken Sterling) wrote in message
...
Gang,
Quick question.... possible situation ... need to tap a hole in, say
1/2" plate, through to the other side, but needs to be "perfectly
aligned" and say the plate is mounted on a piece of machinery that
can't be moved to another location and the tapping has to be done by
hand. Possible solution - is it possible, (or has anyone ever done
this), by grinding a "pilot" on the front end of that tap and then
relieving the cutting edges again to look almost like factory just
behind the end of the pilot? Is this a viable concept?
Ken.