Straight Steel Plate 4PCS 15.7in x 5in Heavy Duty Flat Mending Plate

In this review the Straight Steel Plate 4PCS are evaluated for homeowners, carpenters and DIYers who need a simple but robust solution to repair or strengthen wooden frames and posts. The bottom line: these flat mending plates stand out for their thick Q235B carbon steel construction and black powder coating, which together deliver reliable strength and corrosion resistance for post to beam connectors. If you need a no-nonsense bracket set to reinforce 6x6 lumber connections, this kit is practical and ready to install.

Key Features

• Heavy duty steel: Made from Q235B carbon steel with a 0.12in (3mm) thickness to resist bending and keep joints square under load.
• Corrosion protection: Black powder coated finish provides rust resistance for long-term outdoor or indoor use on pergolas and trusses.
• Generous length: At 15.7in x 5in the plate spans wide connection points so it can bridge damaged or weakened areas for a solid repair.
• Fastener ready: Twelve 0.27in (7mm) diameter nail holes per plate accept the included flat head screws for a strong, flush fastening pattern.
• Complete kit: The package includes four plates and 48 flat head screws so a multi-point repair can be completed without sourcing additional hardware.
• Versatile use: Designed to join vertical and horizontal beams, the plate suits truss frames, pergolas, wooden houses and heavy furniture repairs.

Who It's For

This product is aimed at property owners, deck and pergola builders, and handypersons who need to repair wobbly or broken wooden frames quickly with a sturdy metal solution. It is especially useful where 6x6 lumber or similarly large posts are involved and a long, flat strap is needed to spread the load across a joint.

Those who should look elsewhere include users seeking decorative hardware or custom-shaped connectors; these are straight, functional flat plates rather than ornamental brackets. Also, if stainless steel or marine-grade hardware is required for constant saltwater exposure, consider a different alloy.

Pros & Cons

Pros

• Sturdy Q235B construction provides reliable strength and resists deformation under load.
• Black powder coat improves corrosion resistance and gives a neat appearance on outdoor structures.
• Includes 48 flat head screws so multiple plates can be installed immediately without extra purchases.

Cons

• Not stainless steel; in very aggressive coastal environments additional corrosion protection may be advisable.

Specifications

Material	Q235B carbon steel
Finish	Black powder coated
Plate size	15.7in x 5in (400mm x 127mm)
Thickness	0.12in (3mm)
Number of holes	12 per plate, 0.27in (7mm) diameter
Package contents	4 plates and 48 flat head screws

Our Verdict

The Straight Steel Plate 4PCS kit is a practical, value-oriented choice for reinforcing post to beam connections and repairing truss frames. Its thick Q235B steel and powder coated finish make it a durable option for most outdoor and indoor wood repairs, and the included screws mean projects can start immediately. Recommended for homeowners and builders who prioritize strength and simplicity.

Frequently Asked Questions

Can these plates be used on 6x6 lumber?
Yes, the plate length and hole pattern are well suited to reinforce connections involving 6x6 posts and similar large timbers.

Are screws included for installation?
Yes, the package contains 48 flat head screws so all four plates can be fastened without buying additional fasteners.

Will the powder coat prevent rust outdoors?
The black powder coated finish provides good corrosion resistance for general outdoor use, though stainless steel may be preferable in harsh coastal environments.