Metallics TX121SS 12-14 x 1 in. 5/16 Hex Head Metal to Metal Self-Drilling Screws with Bonded Washer - #3 Drill Point - 410 Stainless Steel - Each

The TX121SS carries a #3 drill point and is rated for panel thickness of 0.110 to 0.210 in. That covers metal roof and wall panel into steel framing like purlins and bar joists. Thinner gauge sheet metal only needs a smaller point, and heavier structural steel is past what this point will cut.

Yes, a bonded washer is factory assembled to the screw. Washer OD runs 0.398 to 0.432 in. and washer thickness 0.022 to 0.039 in., so it seats under the 5/16 hex head and seals the hole on exposed panel work. Nothing extra to buy.

It is a 12-14 diameter screw, 14 threads per inch, 1 in. long, made to SAE J78-2013 thread standard and ASME B18.6.3-2010 dimensions. With panel thickness of 0.110 to 0.210 in. plus the washer, 1 in. leaves adequate thread to engage purlin or bar joist framing. Thicker assemblies or stack-ups need a longer screw.

Metal to metal only. It is a Type BSD self-drilling screw with a drill point, intended for metal panel and standing seam roof clips into steel framing. Fastening panel over wood purlins or nailers calls for a sharp-point wood screw with a sealing washer instead, since a drill point will not hold thread properly in timber.

A 5/16 hex driver or socket. Head width measures 0.305 to 0.312 in. with 0.34 in. across corners, and head height is 0.139 to 0.155 in. Hex drive only, so run it with an impact or a screwgun with a magnetic hex bit holder.

The TX121SS is 410 stainless steel, a hardenable martensitic grade, which is why it can be heat treated to Rockwell C38-46 and still cut its own hole in steel. That hardness is what lets a stainless screw drill; 300 series stainless cannot be used as a self-driller on its own. Paired with the bonded sealing washer, it is built for exposed panel and standing seam clip work.

Minimum torsional strength is 92 lb-in on this 12-14 screw. That is the figure to check against your screwgun or impact setting, since over-driving a self-driller into heavier purlin steel is the usual cause of shear-off. Back the clutch down if heads are twisting off.

No. The TX121SS is not Buy American compliant and is not ARRA compliant, with country of origin listed as multiple. If your contract carries a domestic sourcing clause, this is not the fastener to specify.

They ship in a jar, with a 100 count order minimum. Other sizes and quantities are available by request if a job needs a different length or diameter.