4C collet - Why?

I was thinking for my Clausing a 4C collet closer would be great.
Bigger than the standard 3AT and smaller than the 5C so that it fits in
the spindle without the big overhang.

When it's said and done a 5C collet chuck, or a home made overhanging 5C
closer, is probably the best way to go. Chucks are as cheap as $250
and with 4C I would be very limited on accessories.

BUT, I sure as hell can't afford to buy them from Hardinge!