4” American made Buck 6 jaw adjust-tru lathe chuck, complete with both sets of jaws, chuck key and "speed" key.  Chuck mounted on a modified Morse taper 3 backplate.

Chuck was mounted on a truncated MT3 backplate and threaded to mimic an inserted 3c collet in its sleeve.  The chuck was used briefly in a small South Bend lathe, mounted directly in the spindle and anchored via the 3c collet drawbar.  This puts the chuck in direct line with the spindle for improved accuracy and, more important for us,  kept the chuck from spinning loose when the lathe was run in reverse.

The 3MT shank is also center bored and tapped 1/2-13 and can be anchored via a threaded rod through the spindle bore.  We even once mounted this on a 13” South Bend using its spindle to MT3 adapter sleeve via a threaded rod, washer, and nut.  Chuck could be mounted on many small lathes with 3MT spindle nose regardless of spindle threads by using an appropriate anchoring system via the spindle bore.

Chuck key is a  1/4” and we found an 1/4” socket extension handy as a "speed key" convenient for rapidly adjusting and changing jaws (an adapter is included).

May need a little cleaning. Stored for a long time. Surplus to shop needs as we have gone to adjust tru chucks on larger lathes.

AS IS.