The most prominent use mentioned for the Keats, if not the only one in many cases,
is for machining the crankpin on a crankshaft and it is highly likely that this is
the reason for its design being produced in the first place. This use is though a
subject that I only have limited experience of, just four very small crankshafts
where I have used other methods. Whilst items can be set off centre using the four
jaw chuck the distance is very limited and far short of what is needed when machining
a crankshaft, because of this, the Keats is the only viable option for larger shafts.
In the case of smaller crankshafts, such as on Stuart steam engines, a fixture is
almost certainly the best approach.
Having made these comments it would seem that the Keats angle plate has no purpose
in the home workshop unless larger crankshafts are to be made though some may use
the Vee angle plate for smaller shafts. This though overlooks the fact that they
can both find applications beyond this one task. Typically, as the Keats is likely
to be able to hold diameters larger than the available chucks then it can take their
place when larger diameter work exists, Photograph 4 being an example.
These devices are not though limited to just being used on the faceplate and using
them on the milling machine table prove useful in some cases, particularly as they
are able to hold round workpieces much more securely than say a vice or an angle
plate. A good example being that shown in Photograph 5 where a hexagon for a large
nut is being made and being indexed for the task whilst mounted onto a rotary table.
There is however, another advantage compared to the workpiece being brought to the
rotary table already fitted in the three jaw and screwed to an adapter mounted onto
the table, Photograph 6. This is, that if attempting to use the chuck in this way
the rotation of the cutter will attempt to unscrew it from the adapter, the method
should not therefore be used under any circumstances as it is potentially very dangerous.
The workshop owner should not therefore overlook these other uses and will no doubt
find that they will, on occasions, make a very difficult task relatively easy, or
an impossible task, possible.