Text (18 of 20) in CHEMCLAD: Product Description
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For corrosive applications, 300 series (H-3) and 316 stainless
steel fasteners are typically specified.
Type A point screws - (3/8" hex head) for fastening to wood structures, light gage metal (14 Ga. or lighter). Includes a 15 mm dia. seal washer (unless noted otherwise).
Type B point screws - (3/8 hex head) for fastening to 12 gauge and up to 1/2" thick steel members. Includes a 15 mm dia. seal washer (unless noted otherwise).
SB2 Grommet - (5/16" hex head) for panel-to-panel fastening at sidelaps and FRP flashing. This is a grommet type fastener with a stainless steel machine screw, brass nut, and rubber sleeve.
Pilot holes must be drilled in the support members for stainless steel Type A and B screws. Correct hole sizes are critical to the installation of A and B fasteners. Choose the correct bit size from the Drill Bit Selection Chart found in the item titled "Fastener and Sealant Guide".
Drill pilot holes at a very slow speed. High speed drilling will harden the inside of the hole making it difficult for the fastener threads to bite (thread rolling). This will cause bits to wear out faster than normal. Using a drill bit lubricant can extend the usage of the bits.
Drive all screws at 600 RPM or less. Avoid excessive speed and heat build-up. If thread rolling occurs, lubricate screws with a drill bit lubricant. For 316 stainless fasteners into hard steels, you may need to tap the hole with a heat-treated type B carbon steel screw before installing the stainless steel fastener.
Tighten screws until sealing washer extrudes slightly beyond the metal washer. DO NOT OVER TIGHTEN SCREWS - this can - damage panels and fasteners.