The method I have use when this occurs, and it frequently does, is to tap two holes
in the outer half of the block, one on either side of the hole for closing the block.
These are then fitted with socket grub screws that are used to jack open the block,
Sk 1. The studs with the two nuts should still be fitted and adjusted as initially
intended. Actually, in my case this was not necessary as the holes hardly changed
Spindle Mounting Bracket C4 Cut two pieces of 50 x 12 to 85 mm plus and finish to
length. Mark out the position for the 44 mm diameter hole on one plate only and centre
drill. Stack the two plates and using the tailstock centre position them on the faceplate
and clamp in place and balance as necessary, then bore the 44 mm diameter hole. A
piece of thin card will help to avoid the boring tool contacting the faceplate, but
additionally fitting and adjusting the saddle stop should be considered essential.
A couple of pieces of thin film double adhesive between the two parts prior to placing
on the faceplate will make the process easier. To ensure that the lower edges are
in line stand them on the surface plate as you bring them together.
Mark out and drill and tap the other holes also make the slot as per drawing.
Leadscrew Operating Handle and Dial C6 to C10 These five parts are all relatively
simple to make but the purpose of each needs consideration when finalising some parts
to dimension. The 10 mm diameter on the operating handle pin (C6) needs to be a free
fit in the outer (C7) whilst the 28 mm length of the pin should be marginally longer
than the 28 mm of the outer. This will ensure that the outer runs freely when eventually
Similarly, the 4 mm and 16 mm dimensions on the leadscrew bush (C10) needs to be
marginally greater than the 4 mm and 16 mm dimensions on the leadscrew dial, whilst
the 20 mm bore should be free running on the 20 mm outer diameter, These all ensuring
that it will be possible to reset the dial when it is in use.
Finally, for the column assembly, calibrate the leadscrew dial. This will depend
of course on the chosen pitch of the leadscrew but will in any case require two,
maybe three, different line lengths. First, go round the complete dial making all
lines the same length using a saddle stop to make this easily possible, Photograph
14. Mark the lines that have to be longer with a felt tipped pen, or similar, and
with the saddle stop reset lengthen these lines. Repeat this if a third length is
required, typically for ten's, five's and units. Photograph 15 shows how the lathes
spindle can be used for dividing.