On Wed, 6 Jul 2005 20:45:24 +0000 (UTC), wrote:

OK then, once you've done the scribing, rotate the toolpost ( if a two or
four way ),

Got a 4-way, yes.

or use another toolholder if you have a QCTP. In place of a
tool, insert a bit of 1" sq. bar through which you have previously (note
the catch?) drilled a hole using a 1/4" drillbit held in the lathe chuck,
thereby ensuring the hole is exactly at centre height. Once drilled, mark
the top of the bar ao it never goes in upside down. Now you can bring this
up to your marks with a 1/4" body centre drill inserted & use the cross
slide to position the centre drill on the PCD.

So, the height is constrained by the nature of the tool holder, and the
alignment is taken care of by making sure the bar is flush against the
work. Only trick is getting it aligned to drill the original hole,
which I should be able to reference against - what, the face of the
chuck?

So is this voice of experience here, or are you making this up on the
fly? Either way, it's impressive. The big problem with making this up
as I go along is that I haven't been exposed to creative techniques like
this, but of course once explained they make perfect sense.

Turn the centre drill with
a cordless drill to start each hole, then complete on the drill press. Or
you could make a Dremel mount to fit at centre height in the toolpost &
drill the holes directly with that Or
George Thomas' book the "ME Workshop Manual" has plans for a toolpost
mounted hand turned spotting drill.

So "spotting drill" is the critical term here?

Or, if you are brave enough, try " Sigh... what I really need to do this
easily love, is a jig borer. There's one on Ebay in Czechoslovakia for
only $1500. We could spend a week there, I hear the Skoda works is worth a
look"

I think I'll stay with the home-made stuff, at least for now.

Thanks,
Dave Hinz