Joseph Sullivan writes:

> It really seems impossible without putting some kind of disk in 
> between the
> shaft and the jaws, but that would seemingly cause a problem when the 
> jwas
> are tightened and the disk balks at running up further in the head.

However, Joe, I think you have the solution there.  At least, I have 
some eggbeaters (I have not pulled them all apart) where a disk provides 
a floor for the jaw pieces. The inside cavity of the chuck is 
parallel-sided for some part of the way before it begins to constrict, 
but the jaw pieces become locked together through the end of the shell 
before the disk reaches the full extent of its travel.

As I recall, the threaded shaft in at least some of my eggbeaters 
concludes or has been turned off with a small, central knob which bears 
against the disk to reduce the friction which otherwise would be 
produced should the whole area of the end of the threaded shaft bear 
against the disk.

The springs push the jaw pieces apart as the chuck is loosened in 
addition to keeping the pieces in proper relativity to each other.

Regards from Brisbane,

John Manners 

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