large slotted screwdriver

[Phil Bondi]

Hi all.

I had a large slotted screwdriver that fit in a brace and 
bit..where can I find a suitable replacement?

A quick on-line search didn't produce what I'm looking for:

A big wankin' slotted screwdriver to fit in a drill for 
tightening plates.

suggestions?

-Phil Bondi(Fl)