Stop Bar Support (7)
Turn a short length of Morse taper, and bore the 6mm hole, concentricity for this
is important, part off and the part is complete. There are a number of other parts,
being simple, I do not intend to mention.
Workpiece Support (9)
This heading covers a number of items all performing the task of supporting, or as
an end stop, to the workpiece. Manufacture is very simple but I would suggest that
you bore the 6mm holes though this is most important for the 20mm and spider support.
In these two cases, mount the backstop assembly, complete with the Stop Bar Support,
in the lathe's mandrel and mount these onto the Stop Bar for machining the workpiece
supporting face, thereby ensuring that it will run reasonably true when being used
as a support face. Photograph 10 shows the spider support face being machined.
Incidentally, the three holes for the arms were drilled using the method mentioned
earlier but as the central hole is not a through hole a screw had to be used and
its thread turned away to produce a 6mm spigot. This was then fixed in the central
portion of the spider using the tapped hole to secure it.
The spider support is though more likely to show an error due to its size and should
the reader feel that a more accurate result is required a much more engineered version
was published in issue 117 of the Model Engineers’ Workshop magazine, it is though
in terms of just the spider a much more time consuming item to make. My suggestion
is to make this spider and if considered inadequate then not much time will have
been wasted, the reader can then make the one referred to above.