| Product Name | China wholesale galvanised metal hexagon head tek wood stainless steel hex self drilling screw with epdm washers roofing screw |
| Size | M2-M24,or non-standard as request&design |
| Material | Stainless Steel,Alloy steel,Carbon Steel,Brass,Aluminum and So on |
| Grade | 4.8,8.8,10.9,12.9.etc |
| Standard | GB, DIN, ISO, ANSI/ASTM, BS, BSW, JIS etc |
| Non-standards | OEM is available, according to drawing or samples |
| Finish | Plain, black, zinc plated/according to your requirement |
| Certification | ISO9001,IATF16949, |
| Package | according to customers requirement |
How are self drilling screws measured?
They are measured from the top of the head to the tip. Hex and hex washer head screws and bolts, although flat on the top and the bottom, are measured from the bottom of the head. From that point to the tip is the length of the screw. Self drilling screws are measured all the way to the end of the drill point tip.
Do you need a pilot hole for self drilling screws? While self-tapping screws will tap a hole into a soft material, self-drilling screws are capable of drilling a hole into anything from metal to wood. This key difference is self-drilling screws have a tip like a drill bit, so they do not need a pilot hole.
Do you need a pilot hole for self drilling screws? While self-tapping screws will tap a hole into a soft material, self-drilling screws are capable of drilling a hole into anything from metal to wood. This key difference is self-drilling screws have a tip like a drill bit, so they do not need a pilot hole. 
