The major difference is with there being two clamping screws on each jaw making it
possible to tilt the jaw face. Once one becomes aware of this the difficulty that
results is minimal and can work to one's advantage in some cases and in any case
mainly applies to set ups as seen in photograph 20. The way to proceed with round
items is to first use just the clamp screw furthest from the body face and set the
workpiece to run true adjacent to jaws. With that done the outer end can then be
set true by using the inner clamp screws which is really an advantage as with the
conventional chuck one would have to accept just what resulted, with this set-up
both ends can be set true.
Can use a mix of jaws and workpiece clamps
Has deeper jaws than a comparable sized chuck, *35mm compared to 20mm
With the jaws still within the perimeter of the body it takes much larger diameters
than a comparable sized chuck, *83mm compared to 58mm
Total projection from the lathe's mandrel mounting surface is less, *65mm compared
Much more adaptable for complex shaped workpieces
With the clamping screws having a much finer pitch clamping pressure is much more
Reversing the jaws, which is a slow process, is not required.
Much easier to keep the mechanisms clean
Can be used without the jaws as a very adaptable faceplate.
*Comparisons are with my 6" four jaw chuck.
If the viewer makes much use of the four jaw and faceplate then this alternative
form will provide some useful additional capabilities. Whilst for the viewer who
has yet to acquire a four jaw chuck then it is an option worth considering, saving
money, and also providing an interesting project.