MaterialCarbidePurposeUsed to drill and countersink titanium with HSS cutter or fiberglass and graphite with solid carbide cutter on G39 or G400 Gen Drivmatic RiveterUsed WithG39, G400, ST1016-A-2TypeDrill/CountersinkDrill Size (in)0.250Rivet Size (in)7/32Drill Length (in)3/8