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
In a kitchen, bathroom, or lab, a standard zinc nut corrodes where moisture sits. This square insert uses a stainless steel nut that resists it, pressing inside the leg with the same flexible-rib grip as the standard version. For 30 × 30 and 40 × 40 mm square tube, 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 square threaded inserts use a zinc-plated steel nut. Zinc works well in dry indoor environments. But in kitchens, bathrooms, food service areas, laboratories, and any space where moisture, steam, or cleaning chemicals contact the furniture, zinc corrodes. The nut degrades, the threads roughen, and the leveling foot becomes difficult to adjust or seize entirely. Stainless steel square threaded inserts replace the zinc nut with stainless steel that resists the corrosion these environments create. Same PA body. Same press-fit installation. Same leveling foot compatibility. The only change is the nut material. Also referred to as corrosion resistant square threaded inserts, stainless steel leveling foot inserts, square threaded inserts stainless nut, or waterproof square tube inserts.
PA (polyamide) body for tube grip and load transfer. Stainless steel threaded nut for corrosion resistance. Stainless steel square threaded inserts are corrosion-resistant square threaded inserts for hollow square furniture legs in wet, humid, or chemically active environments. 2 tube sizes: 30 × 30 and 40 × 40 mm. M8 and M10 threads. Wall thickness 1 to 2 mm. Black and grey.
The nut is the only metal component in a threaded insert. PA does not corrode. But a zinc-plated steel nut corrodes when exposed to the conditions common in kitchens, bathrooms, food service, healthcare, and industrial environments. Stainless steel square threaded inserts address this specific vulnerability.
Stainless steel resists all of these conditions. The threads stay smooth. The foot turns freely. The load capacity remains constant.
Same measurements as standard square threaded inserts: tube dimension, wall thickness, and thread size. Stainless steel square threaded inserts are available in 30 × 30 and 40 × 40 mm with M8 and M10 threads.
Use calipers across one side of the square tube, outside edge to outside edge. Confirm both sides are equal. The dimension must be 30 or 40 mm for stainless steel inserts.
Use calipers at the tube end. The wall must be between 1 and 2 mm. The PA body ribs are the same as standard inserts and require this wall range for proper grip.
Check your leveling foot’s thread specification. Stainless inserts are available in M8 and M10 only. For M12 in a corrosive environment, contact Business Solutions for custom options.
Identical to standard square threaded inserts. The stainless steel nut does not change the installation process. Align corners to corners, nut facing the floor, press in by hand, and tap with a rubber mallet until flush.
Every benefit of standard square threaded inserts, plus corrosion immunity at the threaded connection. The National Wood Flooring Association (NWFA) recommends protective measures on all furniture legs, and stainless steel square threaded inserts deliver that protection in environments where standard zinc-plated inserts would degrade.
The primary advantage. In commercial kitchens where floors get washed daily, in bathrooms where humidity is constant, in food processing facilities where acids and cleaning chemicals contact every surface, stainless steel square threaded inserts maintain smooth, functional threads for the life of the furniture. The leveling foot turns freely every time. No seized threads. No rust stains. No reduced load capacity from corrosion weakening.
A corroded zinc nut eventually seizes or fails, requiring the entire insert to be replaced. In commercial kitchens with dozens of tables, replacing corroded inserts is a recurring labor cost. Stainless steel square threaded inserts eliminate corrosion-driven replacement. The initial cost is higher than zinc, but the total cost of ownership is lower in corrosive environments because the inserts do not need replacement due to corrosion. Unlike leaving furniture unprotected in harsh environments, the stainless steel connection maintains function over the full service life.
In food service, healthcare, and laboratory environments, corroded metal components are a hygiene concern. Rust flakes can contaminate surfaces. Corroded threads trap bacteria. Stainless steel is the standard material for food-contact and hygiene-critical hardware. Stainless steel square threaded inserts bring that hygiene standard to the furniture leveling system.
Tube sealing, floor protection through leveling feet, noise dampening, and height adjustment. The stainless nut does not change any of these. The PA body seals the tube. The leveling foot contacts the floor. The threaded connection provides adjustment. Stainless simply ensures the nut survives environments that zinc cannot.
The decision between zinc and stainless steel is an environmental decision, not a furniture decision. The same table in a dry office uses zinc. The same table in a commercial kitchen uses stainless steel. The furniture design does not change. The operating environment determines the nut material.
Office buildings, conference rooms, residential dining rooms, retail showrooms, hotel lobbies, classrooms, libraries, and any standard indoor space with climate control and normal cleaning. These environments do not expose the insert to sustained moisture or aggressive chemicals. Zinc-plated nuts from standard square threaded inserts provide adequate corrosion resistance for the life of the furniture in these conditions.
Commercial kitchens, restaurant dish areas, hotel laundry rooms, bathroom and locker room furniture, pool deck furniture, healthcare examination rooms, dental offices, veterinary clinics, laboratories, food processing plants, brewery taprooms, winery tasting rooms, and any outdoor covered area. These environments expose the insert to regular moisture, steam, cleaning chemicals, or food acids that attack zinc plating. Stainless steel square threaded inserts are the correct specification for all of these applications.
If you are unsure whether your environment requires stainless, ask: Does the floor around the furniture get wet at least once a day? If yes, specify stainless. If no, zinc is sufficient. For environments that fall in between (occasional spills but not daily washing), stainless is the safer long-term choice because even infrequent moisture exposure accumulates over months and years.
| Fits Tube (W) | Fits Tube (L) | Thread (M) | Static load (SL) |
|---|---|---|---|
| 30 mm (1.18″) | 30 mm (1.18″) | M10 | 120 kg |
| 30 mm (1.18″) | 30 mm (1.18″) | M8 | 80 kg |
| 40 mm (1.57″) | 40 mm (1.57″) | M10 | 120 kg |
| 40 mm (1.57″) | 40 mm (1.57″) | 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 | 4 sizes |
| Width (W) | 30 to 40 mm (1.18″ to 1.57″) |
| Length (L) | 30 to 40 mm (1.18″ to 1.57″) |
| Height (H) | 16 mm (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 |
Choose stainless when the insert will be exposed to moisture, humidity, steam, cleaning chemicals, or any substance that corrodes zinc. Commercial kitchens, bathrooms, food processing areas, outdoor covered furniture, pool decks, laboratories, and cleaning-intensive healthcare environments all benefit from stainless steel nuts. In standard indoor office or residential environments with no unusual moisture, zinc-plated standard square threaded inserts are sufficient.
The PA (polyamide) body does not corrode. PA is inherently resistant to moisture, chemicals, and biological degradation. Only the threaded nut is metal, so the nut is the only component where corrosion is a concern. Stainless steel addresses the nut. PA addresses the body. Both materials resist the environments that destroy zinc.
Stainless steel has comparable strength to zinc-plated steel at M8 and M10 thread sizes. Load capacity through the threaded connection is effectively the same for all furniture and equipment applications. The difference is corrosion resistance, not mechanical strength.
These are the square tube sizes most commonly used in commercial kitchens, bathrooms, and food service furniture where corrosion resistance matters most. For stainless steel inserts in other square sizes or in round and rectangular tubes, contact Business Solutions for custom production.
Yes. The M8 and M10 thread interface is identical to zinc-plated inserts. Any M8 or M10 leveling foot from our adjustable leveling feet range screws into a stainless insert the same way. The stainless steel only affects corrosion resistance, not thread compatibility.
Stainless Steel Square 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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