On Tue, 20 May 2008 21:16:01 +0100, David Billington
wrote:

SNIP

I think that is not quite correct, both the Dickson and Bison (Dickson
copy) toolholders I have are fitted with a threaded stud into the top of
the toolholder, the height adjustment knob screws onto this stud and
into the top of the knob is threaded a square headed set screw. The
height adjustment knob can be locked at the desired height by tightening
the set screw against the top of the stud. The locking cam pulls the
tophat plunger in to pull the toolholder to the toolpost and at the top
of the cam is a shelf that the height adjustment knob rests on.

Hey David,

Hmmm....maybe we are in agreement...not sure.

All my Dickson toolholders have a height adjustment that is shaped
like a spool like thread comes on. The "upper" edge of the spool is
knurled and used to set the height of the tool-holder. The "bottom"
of the spools sits atop a "shelf" of the locking cam on the tool-post
block. This cam also has an "upper" shelf , which straddles the lower
spool edge to assure the location.

Is that what you meant?

Take care.

Brian Lawson,
Bothwell, Ontario.