3/8" Thick 6.125" OD Round Aluminum Backing Plate | 6-Hole 5/16" | Marine Grade 6061-T6
Part Number: 0067
Six-Hole Round Backing Plate
Precision CNC-machined 6061-T6 aluminum round backing plate with six 5/16" through-holes. Designed to pair specifically with SKU 0030 (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 0030 for perfect alignment. Chamfered for deburring only.
| Material | Marine Grade 6061-T6 Aluminum |
| Outside Diameter | 6.125" OD |
| Thickness | 3/8" (0.375") |
| Holes | 6 through-holes (5/16" dia.) |
| Shape | Round |
| Finish | Matte — tumbled, deburred, paint/powder coat ready |
| Pairs With | SKU 0030 — 6" OD 6-hole countersunk pad |
| Weight | 0.99 lb |
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 the backing plate, locking the assembly together and distributing fastener loads to prevent damage to the fiberglass.
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.
Does this plate replace a countersunk pad?
No — this backing plate is designed to work specifically in combination with SKU 0030 (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 complete the assembly. They share the same bolt-circle pattern for perfect alignment.
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- One Business Day Shipping
- Call us Mon.-Fri. 9:00 a.m. to 4:00 p.m. if in any doubt.
Due to this item's size and weight we can only ship it in an economical way via Less Than Truckload (LTL) consolidated land shipping, and only to the contiguous 48 States.
For shipping inquiries to AK, HI, PR, US-VI, and international shipping, please contact us first at sales@weldingworldinc.com.
All of the destinations above we can only serve as a Free Carrier (or FCA) modality, that requires the customer to contract and pay for their carrier service of choice. We can still ship the item, but only to a warehouse/receiving office within the 48-contiguous States.
In plain terms what this means is that if you want to ship your product to any non-contiguous US territory or internationally, you, the customer, has to provide us with the warehouse address of the carrier that serves your locality with an address within the contiguous 48-US States, as we do not ship overseas on our own.
