Hospitality-grade floor protection · Sizing help before you order · Apply for a business account
Sizing help · Apply for a business account
Hospitality-grade floor protection · Sizing help before you order · Apply for a business account
Sizing help · Apply for a business account
A hollow rectangular leg has no way to take a leveling foot on its own. This insert presses inside and grips both the short and long walls with flexible ribs, bringing a pre-installed zinc-plated nut ready for any matching foot. Three tube sizes, M8 and M10 threads. Black and grey.
We make this size in production runs, so there is none on the shelf today. Tell us how many you would want and you go on the list for it. When enough people ask for a size, we run it, and the people who asked hear about it first.
We stock a limited range of tube sizes and wall thicknesses. Tell us the size you need and we will confirm availability and pricing by email.
Buying in volume? See business pricing & samples ↓
Standard rectangular tube plugs seal the tube end and protect the floor. But they cannot accept a leveling foot. Rectangular threaded inserts do both: they press inside the hollow rectangular tube with a ribbed PA body that grips both the short walls and the long walls, and they add a pre-installed zinc-plated steel nut that accepts any adjustable leveling foot with a matching M thread. Tube sealing, floor protection, and threaded height adjustment in a single press-fit installation for rectangular profiles. Also known as rectangular tube leveling foot inserts, threaded inserts rectangular furniture, or rectangular tube inserts with nut.
PA (polyamide) body for strength under load. Zinc-plated steel nut (Fe HDG) for corrosion resistance and thread durability. Rectangular threaded inserts are threaded inserts for rectangular tube legs on tables, desks, sled base frames, commercial fixtures, and any hollow rectangular-legged furniture that needs adjustable leveling. 3 tube sizes: 20 × 40, 30 × 50, and 30 × 60 mm. M8 and M10 threads. Wall thickness 1 to 2 mm. Black and grey.
Two components in one product. The PA body press-fits inside the rectangular tube and grips both the short and long interior walls with flexible ribs. The zinc-plated steel nut is pre-installed in the center of the PA body. A leveling foot screws into the nut, and the nut transfers the load through the PA body to the tube walls.
Align width to width and length to length. Push in by hand or tap with a rubber mallet. The PA body grips all four walls. The insert seals the tube end and anchors the nut.
Any leveling foot with the matching M thread (M8 or M10) screws directly into the nut. No drilling, no tapping, no additional hardware.
Turn the leveling foot to raise or lower that corner. Each leg adjusts independently to eliminate wobble and level the furniture on uneven floors.
Three tube measurements plus the thread size. Width (short side), length (long side), wall thickness, and the M thread of your leveling foot. All four must match.
Use calipers across each side of the rectangular tube, outside edge to outside edge. Record the short side (width) and the long side (length). Available sizes: 20 × 40, 30 × 50, and 30 × 60 mm. Always list the shorter dimension first.
Use calipers at the tube end. The wall must be 1 to 2 mm. Then confirm your leveling foot’s M thread. The 20 × 40 mm supports M8 only. The 30 × 50 and 30 × 60 mm support both M8 and M10.
Same press-fit installation as standard rectangular tube plugs, with attention to both rectangular orientation and nut direction. Two alignment requirements: width-to-width plus nut-toward-floor. A rubber mallet is recommended.
Everything a standard rectangular tube plug provides, plus adjustable leveling through a threaded connection. The National Wood Flooring Association (NWFA) recommends protective measures on all furniture legs, and rectangular threaded inserts deliver that protection while adding the height adjustment that standard plugs lack.
The primary function. Tables with rectangular tube legs wobble on uneven floors. Sled base frames sit unevenly when the floor is not perfectly flat. Rectangular threaded inserts provide the M-threaded connection that leveling feet require. Each contact point adjusts independently.
The leveling foot becomes the floor contact surface. Most leveling feet have base pads that protect floors better than bare metal or PE. Unlike leaving rectangular furniture legs on an unlevel bare metal surface, the combination of an insert plus a leveling foot provides both adjustment and protection. Browse our adjustable leveling feet for base pad options.
A unique application for these inserts that round and square inserts rarely handle. Sled base chairs and tables use rectangular tubing for the runners. The open runner ends are the natural location for threaded inserts and leveling feet. Rectangular threaded inserts press into the runner ends, and leveling feet screw in to provide adjustable contact at each end of each sled. This is especially valuable on uneven floors where the sled would otherwise rock from front to back.
Same sealed end as standard rectangular tube plugs. The PA body fills the rectangular opening and prevents moisture, debris, and insects from entering. On steel tubing, sealed ends prevent internal corrosion. The nut does not compromise the seal because it is embedded within the PA body.
Sled base furniture is the application where rectangular threaded inserts provide the most distinctive value compared to round and square inserts. Sled base runners are typically rectangular tubing, and the open runner ends are the natural location for threaded inserts and leveling feet.
A sled base has two runners, each with two open ends. Press a rectangular threaded insert into each of the four runner ends. Screw an M8 or M10 leveling foot into each insert. The four leveling feet provide four adjustable contact points. Adjust each foot independently to level the furniture front-to-back and side-to-side. On uneven restaurant or cafeteria floors, this eliminates the rocking that sled base furniture produces when the runners do not contact the floor evenly.
Most sled base dining chairs use 20 × 40 mm rectangular tubing for the runners. Heavier commercial sled base tables and benches may use 30 × 50 or 30 × 60 mm runners. The 20 × 40 mm rectangular threaded insert with M8 thread is the most frequently specified insert for sled base chair leveling. For sled runners that also need scratch protection along the bottom surface (not just the ends), pair with rectangular self-adhesive furniture pads along the full runner length.
Rectangular threaded inserts are designed for any hollow rectangular furniture leg or sled base runner that needs an adjustable leveling foot.
| Fits Tube (W) | Fits Tube (L) | Insert Depth (H) | Thread (M) | Static load (SL) |
|---|---|---|---|---|
| 20 mm (0.79″) | 40 mm (1.57″) | 14 mm (0.55″) | M8 | 80 kg |
| 30 mm (1.18″) | 50 mm (1.97″) | 16 mm (0.63″) | M10 | 120 kg |
| 30 mm (1.18″) | 50 mm (1.97″) | 16 mm (0.63″) | M8 | 80 kg |
| 30 mm (1.18″) | 60 mm (2.36″) | 16 mm (0.63″) | M10 | 120 kg |
| 30 mm (1.18″) | 60 mm (2.36″) | 16 mm (0.63″) | M8 | 80 kg |
Tube wall thickness is a fit requirement, not a tolerance.
| Specification | Detail |
|---|---|
| Material | Polyamide body with a hot-dip galvanised steel thread |
| Sizes | 5 sizes |
| Width (W) | 20 to 30 mm (0.79″ to 1.18″) |
| Length (L) | 40 to 60 mm (1.57″ to 2.36″) |
| Height (H) | 14 to 16 mm (0.55″ to 0.63″) |
| Head height (H1) | 5 mm (0.20″) |
| Tube wall thickness (T) | 1 to 2 mm (0.04″ to 0.08″) |
| Thread (M) | M8, M10 |
| Static load (SL) | 80 to 120 kg |
| Mounting | Pushes into the tube, takes a threaded foot |
| Colors | Black, Gray |
| Floor compatibility | Hollow tube legs |
| Minimum order | Sold in a minimum of 4, then any quantity you need |
Yes, if the sled base frame uses rectangular tubing and you need adjustable leveling at the contact points. Measure the tube dimensions at the point where you want to install the insert and leveling foot. The 20 × 40 and 30 × 50 mm sizes cover common sled base runner dimensions. The leveling foot screws into the insert at the runner end, providing adjustable floor contact at each end of the sled.
The rectangular tube sizes in this range (20 × 40 to 30 × 60 mm) are typically used on furniture where M8 and M10 provide sufficient load capacity. M12 is available on square threaded inserts in 30 × 30 and 40 × 40 mm for heavier loads on square-legged furniture. For M12 on rectangular tubes, contact Business Solutions.
Yes. Rectangular threaded inserts must enter the tube with the short side aligned to the short side and the long side aligned to the long side. The insert will not fit if rotated 90° because the two dimensions are different. The nut must also face the floor so the leveling foot can screw in from below. Two alignment requirements.
The grip mechanism is the same PA ribbed body. On rectangular profiles, the ribs grip two short walls and two long walls, which may compress to different depths because the wall dimensions differ. The overall grip is comparable to square inserts in the same wall thickness range. Both hold firmly at 1 to 2 mm wall.
Any leveling foot with M8 or M10 thread. The leveling foot does not need to be rectangular. Round-base leveling feet screw into rectangular inserts the same way they screw into round or square inserts. Browse our adjustable leveling feet range for M8 and M10 options.
Rectangular Threaded Inserts
Outfitting a hotel, restaurant, school, healthcare facility, or large furniture build? Superior Glide supports volume orders with bulk pricing tiers, free physical samples, and dedicated quote pricing for accounts placing larger orders.
Bulk pricing tiers, net terms for qualified buyers, and dedicated support for facility managers and procurement teams.
Hold the product, test the fit, check the finish. We ship samples free so you can evaluate before committing to a full order.
For orders above standard volume tiers, we’ll prepare a custom quote with consolidated shipping and your account’s tier pricing.
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