13 years ago
Westbury) milling machine. By the standards of the mills mentioned
here this is probably so small that it would get lost in the workshop!
The design of the cone nuts and micrometer dials has confused me.
Each feedscrew beyond the thrust washer is threaded 7/16x26tpi and the
very end is threaded 3/8 BSF. Onto the 7/16" thread screws a cone nut
which has two flats for a spanner. Then on goes the micrometer dial which
is internally bored to match the cone. A three turn spring follows to
press the micrometer dial onto the cone. Then the strange part, a disc
of 3/4" steel threaded 7/16, followed by a Picador handwheel which is
held on by the 3/8" nut.
I cannot see how one is supposed to adjust this strange locking arangement
for end play. The flats on the cone nut are not accessible to a spanner
once the micrometer dial is in place, but the micrometer dial must be
fitted before the threaded disk and there is no provision for a spanner
to tighten the disk up against the cone nut as a lock nut.
To me it would make much more sense if the threaded disk were bored
clearance size and the locking were effected between the cone nut and
the 3/8" nut securing the handwheel.
However, before changing this I'd like to make sure I have not
overlooked some clever feature of Westbury's original design (or was
this a bizare modification from the original design?).