There are very many designs for cross drilling jigs, Photos 1-3 showing one available
from .Hemingway Kits However, there are many methods that can be applied using
just the normal workshop accessories.
Photo 1 shows that it centralises the drilled hole as the V is is made whilst the
body is mounted on the lathe’s top slide by using progressively smaller end mills,
16mm, 14mm, 12mm, etc. This ensures the V is centred onto the lathes spindle. Photo
2 shows the result. However, I increased the depth by 2mm rather than 1mm as I should
have done, hence the shape.
Photograph 1 showed a drill bush being used whilst in Photo 3 it has been started
first using a centre drill. A drill bush is not needed for every drill size as the
hole can be started using a smaller drill bush and then enlarged with the drill bush
removed. LINK With a drill bush fitted, as in photograph 1, the jig can also
be used on the drilling machine.
Photo 4 One advantage over photograph 5 that follows, as with some other methods
also, is that it is possible to drill two of more holes axially in line and using
the table traverse to set the distances. LINK
Photo 5 uses a toolmakers clamp and a workpiece clamp, the hole being started using
a centre drill and finished with a drill to suit the size of hole required. The method
is particularly useful when a number of identical parts are being made as the workpiece
clamp can be used as an end stop. LINK