Most setups using the four jaw chuck are vary simple even though they are many and
The most obvious use is for them is to hold square, Photo 1, and rectangular workpieces.
Another use for them which makes them all but essential in the home workshop is to
hold round material when it is important that it runs true, Photo 2, This is because
a three jaw chuck, even a precision one, will not hold the material sufficiently
accurate in some cases.
In many workshops the four jaw will have a larger capacity than the three jaw chuck
available, resulting again in the four jaw being used for round workpieces, Photo
Another feature of the four jaw chuck is that it can hold quite irregular shaped
workpieces, frequently castings Photos 4, 5 and 6 show examples
Four jaw chuck, an alternative.
Whilst not exactly a four jaw chuck I am including some pictures of my alternative
to a four jaw chuck, Photo 7.
Photo 8 shows it being used conventionally to hold a rectangular part, and Photo
9 set up as a two jaw chuck.
It is a little slower to set up for the more conventional uses but is capable of
much more that a four jaw chuck. Also, its capacity is much greater than for a similar
size four jaw.
Another feature is that with the jaws removed one has a very robust tee slotted faceplate.
Follow the link to find more details of its advantages and capabilities. LINK