This is a heavy, robust brace with excellent Cocobolo handles.  The two-jaw chuck is very stout and could probably hold round drill bits below 5/16 inch reliably, but there is evidence that someone tried a increase its gripping capacity with a pipe wrench, marring the outside of the chuck but not distorting it or damaging the jaws.  100 percent of the nickel plating remains.  There are no patent dates indicated on the brace, and although the chuck generally follows the Leland patents (US Patent No. 912,582 - Feb. 16, 1909 and No. 974,896 - Nov. 8, 1910) the jaws do not match any Millers Falls patents in the DATAMP database.  The cited patents (details below) illustrate the chucks holding round-shanked bits, however: