If you have a depth micrometer, measure the relation between the vice's base and
the rails on which the keep plate is to slide. Then set up the vice body with the
jaw as in Photograph 6. Space the body from the vertical slide on 3. 2. 1. blocks,
or other suitable parallels, and the jaw clamped to the body using two toolmakers
clamps, one on either side of the vice.
Now machine the base of the jaw on which the keep plate sits. Gradually lower the
end mill until the dimension between the vice and the jaw is 1 thou less than the
dimension taken above. If a depth micrometer is not available then locally lower
the cutter towards the keep plate rails until contact can just be detected, marking
the rail with marking blue will help. Note the leadscrew dial reading, run the cutter
out then in again, one thou short of the reading just taken. This assumes you have
a calibrated lead screw, otherwise it will be a case of the saddle stop and a feeler
Cut a piece of steel for the keep plate, making it long enough to reach the front
of the vice with the jaws closed and the rear of the vice when fully open. Mark out
for two M6 screws to fix the plate to the jaw and drill tapping size for M6. Assemble
body, jaw and plate, holding them together with suitable clamps and drill though
the plate into the jaw. Tap the jaw M6, open up the holes in the keep plate and assemble,
see photograph 3.
When pushed by hand the jaw should be stiff to move, if loose, carefully lap the
base of the jaw a very little on a piece of emery paper and try again, repeat as
necessary. If too tight, then place two pieces of flat bar on a suitable surface
with a strip of emery paper on each and lap the bottom of the jaws sliding faces
by moving the jaw back and forward.
Fit the feed screw and test with that. The screw that drops into the grove in the
feed screw is there just for opening the vice, a steel ball should be present between
the end of the screw and the bottom of the hole to take the closing force. This was
missing from the vice that I purchased. If you do not have a suitable steel ball
then make a little plug.
Now check that the fixed and moving jaws are ninety degrees to the surface on which
the jaw moves, if they are, as they were on the one I modified, the next operation
can be bypassed.