This is a simple assembly, Photograph 3, with only a few areas needing special attention.
Posts (13 and 14)
The first essential feature is that, whilst their length is not critical, all four
posts should be the same, say within +/- 0.03 mm. To do this, set up a backstop in
your lathe bore and drill, tap and face the end of the first post. Reverse the post
in the chuck ensuring that it is now firmly against the backstop. Also fit a saddle
stop and with the saddle firmly against this again drill, tap, and very lightly face
the end of the bar using the top slide to establish the part's length, DO NOT now
move either the saddle or the top slide.
I find it difficult not to instinctively adjust the top slide so, if like me, place
a flag of masking tap on its handle as a reminder not to do so.
Fit the second post and with the saddle away from the saddle stop, face, drill and
tap the first end, then, with the part reversed in the chuck and the saddle now against
the saddle stop, the second end is faced, drilled and tapped ensuring, as a result,
that it is the same length as the first. Photograph 4 shows that I used my three
way tailstock turret to avoid continually changing centre drill, drill and tap and
also that I used the auto feed mechanism from my controlled feed tapping stand. This
makes tapping, even in the lathe, delightfully simple. Repeat for the remaining two
Remove the post and measure its length to determine how much more requires to be
removed, return to the chuck, again against the backstop, and using the top slide
set on the amount to be removed, finally face to length. It is essential that the
top slide is now left in that position for the remaining three posts.
All small pictures can be clicked on to provide a larger view