This was a custom design so the exact specs are not available.  It is solid carbide and the max cutting diameter is 1/2".  The pilot appears to be 15/64" but my measurements could be off +/- a small amount.  The shank is also 1/2" in diameter.  The overall length is about 3-17/32".  The length of the pilot is about 5/16".  The label on the holder is "Chief Butt Hinge" but according to the maker that's just a name given by the customer.