Used for stitching two metal roofing sheets together without the need to pre-drill a hole (Max. 1.6mm). Self-drilling point and tapered shank, with a washered hexagon head. Hardened carbon steel drill tip fused on to an A2-304 Austenitic Stainless Steel body" Thread Dia. mm: 6.3 Length mm: 22 Head Type: Hex Fixed Washer Dia. mm: 11.00 Point Type: Self-Drilling No.1 Reduced Socket Size mm: 8 Material: Bi-Metal/A2-304 Stainless Steel/Carbon Steel Effective Thread Length mm: 9 Max Drilling Thickness mm: 1.6Size 6.3 x 22 - 100 pcs Timco Metal Stitching Screws - For Sheet to Sheet - Hex - EPDM in Silver