1/4" Thick 7.25" x 5" Oblong Aluminum Backing Plate | 6-Hole 5/16" | Marine Grade 6061-T6

Six-Hole Oblong Aluminum Backing Plate

Precision CNC-machined 6061-T6 aluminum oblong backing plate with six 5/16" through-holes. Designed to pair specifically with SKU 0069-B (matching countersunk pad) in a sandwich assembly — the screw enters through the countersunk pad and passes through the mounting surface, and nuts thread onto the fastener behind this backing plate to lock the assembly. Commonly used on top or through the side of a deck pedestal, as well as through the fiberglass skin of a hardtop or T-top. Through-holes match the same bolt-circle pattern as SKU 0069-B for perfect alignment. Solid center — no passthrough hole.

Common Applications

T-tops, tuna towers, hard tops, radar arches, leaning posts, grab bars — used as a backing plate behind a countersunk pad in through-bolted assemblies on top or through the side of deck pedestals, and through fiberglass skins on hardtops.

Frequently Asked Questions

What is a backing plate?
A backing plate sits behind a countersunk pad in a sandwich assembly. The screw enters through the countersunk pad and passes through the mounting surface — whether on top of a pedestal, through the side of a pedestal, or through the fiberglass skin of a hardtop or T-top — and nuts thread onto the fastener behind this backing plate, locking the assembly together and distributing fastener loads to prevent damage to the fiberglass.

Why no center passthrough on this plate?
This backing plate has a solid center — no passthrough hole. The matching CS pad (SKU 0069-B) has the 1.5" center passthrough for cable and hose routing. The backing plate only needs the 6 through-holes for the fasteners.

What size fasteners does this plate use?
The six through-holes are 5/16" diameter, sized for 1/4" bolts or screws with washers. Use 1/4"-20 stainless hardware for best results.