Biaungdo Furniture Leg Mounting Plates, 4 Sets 5/16 Attachment Plates with Hanger Bolts Screws for Furniture Sofa Cabinet Chair Couch Seats Strengthen Weak Furniture feet Repair Plates

Why I reached for these mounting plates

A wobbly sofa leg is a small failure that makes a living room feel tired. I recently had two projects on the bench: repairing a broken leg on a mid-century sofa and adding short tapered feet to a low vintage cabinet so it could clear baseboards. For both, I used the Biaungdo mounting plates—simple 5/16-inch top plates paired with hanger bolts, T-nuts, and screws—to create strong, repeatable leg connections. They’re not flashy, but in the world of furniture fixes, predictable hardware is exactly what you want.

What’s in the kit

Each kit includes four flat iron plates with a welded 5/16-18 threaded boss, four 5/16-18 T-nuts, four 5/16 hanger bolts (wood screw on one end, machine thread on the other), a dozen M4 x 25 mm screws, and four small mesh rubber pads. The plates are zinc-plated (silver) and arrive cleanly stamped with four mounting holes around the perimeter. The finish is typical of zinc chromate or similar—it shrugs off shop humidity and fingerprints but isn’t meant for outdoor exposure.

On my bench, the threads were cut cleanly with no burrs, and the welded bosses were square to the plates—important so your legs don’t toe in or out once installed. The parts count is generous for a four-leg job, and the inclusion of both hanger bolts and T-nuts gives you two viable mounting strategies depending on what you’re starting with.

Build quality and design

The plates are adequately thick for furniture duty; mine didn’t dish or deform even when I cinched down a leg on the sofa that takes the brunt of daily sitting. The welds around the threaded bosses were neat, and the internal threads took a 5/16-18 bolt smoothly without cross-threading. The zinc finish is uniform with no flaking.

The screws are the weak link. They’re serviceable for softwoods and plywood, but for hardwood frames I preferred swapping to #10 x 1" or 1-1/4" wood screws with a washer. The included mesh pads are a nice touch; used between plate and frame, they help tame tiny squeaks and spread load slightly on soft frames. I also cut one to size as a foot pad under a tapered leg—crude but effective on hardwood floors.

Installation: quick and forgiving

On the sofa repair, I stripped away the old plastic corner block, squared the frame, and mounted a plate flush to the underside rail. I pre-drilled the holes (3/32" for the kit screws, 1/8" for #10 wood screws) and set the plate with four fasteners. The leg’s existing 5/16 stud threaded right in and seated firmly with no play. Total time: maybe 15 minutes including layout and pilot holes.

For the cabinet project, the legs were bare wood blocks with no hardware. I used the included hanger bolts to create my own studs:

• Mark center on the leg bottom and drill a pilot hole sized for the wood thread (I used 13/64" in maple; go smaller in softwood).
• Thread two nuts onto the machine end, jam them together, and use a wrench to drive the wood thread into the leg until the transition shoulder just kisses the wood.
• Back off the jam nuts and you’ve got a straight, solid 5/16-18 stud ready to meet the plate.

With the plates on the cabinet bottom, all four legs spun on easily and tightened up square. A final tweak with a level and the cabinet sat rock solid.

I also tried the T-nut method on a bed rail where I needed a completely flush underside. Drill a through-hole, hammer in the T-nut from the inside of the rail, and you can bolt a leg or bracket from below. It’s the cleaner option when you can access the back side, and it avoids adding the plate’s thickness.

Compatibility and the thread gotcha

These plates are 5/16-18 (coarse). That’s the most common thread for North American furniture legs, but not universal. If your existing leg has a 5/16-24 (fine) stud or an M8 metric stud, it will not fit these plates directly. You’ve got options:

• Replace the stud with the included 5/16-18 hanger bolt.
• Use a thread adapter (M8 to 5/16-18 adapters are easy to source).
• Skip the plate and install the provided 5/16-18 T-nut, then fit a matching stud or bolt.

Before you mount anything, check your leg’s stud with a thread gauge or simply test it in a loose 5/16-18 nut. A quick compatibility check saves you from tearing out screws later.

Load-bearing and stability

Neither the packaging nor product page gives a formal load rating, but in use the plates held up well. The repaired sofa leg has seen daily use for weeks with no creaks, no loosening, and no visible deformation in the plate. The cabinet feels as if it shipped that way from the factory—no racking when pushed laterally, which is the real test for top plates like these.

The caveat is wood substrate quality. Screws need something solid—ideally a hardwood rail or a plywood web. If you’re going into chipboard or a torn-out frame, add a backing block or corner brace first. The plate can only be as strong as what it’s anchored to.

Where these shine

• Repairing broken or pulled-out sofa and chair legs where the original insert failed.
• Adding legs to cabinets, credenzas, and nightstands to clear vents or baseboards.
• Building ottomans and footstools from bare blocks or pre-made legs.
• Swapping leg styles on furniture when the original hardware is missing or nonstandard.

The kit’s versatility is its strongest trait. Between the plate, hanger bolt, and T-nut, you can usually find a path to a solid connection without exotic tools.

Limitations and cautions

• Screws: The included screws are basic. For hardwood, bring your own quality wood screws and pre-drill.
• Corrosion: Zinc plating is fine indoors, but I wouldn’t use these for patio furniture or damp, unconditioned spaces long term.
• Overhead use: The listing mentions chandeliers. I wouldn’t use this kit for any overhead load. Electrical boxes and listed hardware exist for good reasons—use them.
• Thread standard: These are coarse 5/16-18 only. Not compatible with 5/16-24 fine without changes.
• Tolerances: On one of my kits, the accessory pack was missing a couple of screws. Not a showstopper, but have spares on hand.

Tips for a cleaner, stronger install

• Always pre-drill. It prevents splitting and keeps the plate from walking during installation.
• Use larger, quality wood screws for hardwood frames and a dab of wood glue in stripped holes.
• If legs squeak, try a thin washer or the included mesh pad between plate and leg shoulder.
• Tighten by hand first, then snug with a wrench—avoid over-torquing which can strip wood screws.
• If your leg studs aren’t perpendicular, drive the hanger bolts using a small drill-press vise for alignment.

Value and who it’s for

For a modest price, you get four complete leg connection points that cover most DIY and repair scenarios. The material quality is good for indoor furniture, the threads are consistent, and the hardware assortment reduces the number of extra trips to the store. If you’re a renter doing quick upgrades, a DIYer rescuing curb finds, or a pro who needs a dependable “fix-it” kit in the van, these plates make short work of loose or missing leg hardware.

Recommendation

I recommend the Biaungdo mounting plates for indoor furniture repairs and retrofits where a 5/16-18 connection is appropriate. They’re sturdy, straightforward to install, and flexible thanks to the included hanger bolts and T-nuts. Plan on bringing your own wood screws for hardwood frames and verify thread compatibility before you start. Within those bounds, they deliver exactly what they should: a solid, square, reliable leg connection that restores function without drama.