Square metal threaded inserts provide reliable, high-strength connections for square tubing across a range of projects—from DIY furniture to industrial frames. This guide highlights five top options designed to fit specific square-tube sizes, with strong threads and secure retention. Each product features a star-type or threaded design to maximize grip and reduce slip. Whether you’re mounting casters, brackets, or accessories, these inserts help you achieve a stable, flush finish while maintaining ease of installation and compatibility with common screws.
Summary of selected products
| Product | Brand | Thread | Size (Outer Diameter) | Pack |
|---|---|---|---|---|
| Micro Traders Square Tubing Insert | Micro Traders | 1/4-20 | 19 mm OD square tube | 8 pieces |
| Outwater Double Star Threaded Caster Insert | OUTWATER | 3/8-16 | 1 inch square tube | 4 pieces |
| Metal Star Type Insert (1″) | Magic Hub | 1/4-20 | 1″ OD tubing | 4 pieces |
| Square Tubing Star Type Insert 1″ | Magic Hub | 1/4-20 | 1″ OD tubing | 4 pieces |
| Threaded Inserts For Square Tubing 1-1/4″ | Magic Hub | 1/4-20 | 1-1/4″ OD tubing | 4 pieces |
Micro Traders Square Tubing Insert
Designed for square tubes with an outer diameter of 19 mm and a wall thickness of 1.5 mm, this insert installs tightly without adjustment. It uses a 1/4-20 thread to match standard screws for a firm connection and stability. The internal plum flower spring design provides reliable grip, enhancing the connection between the nut and the square tube.
Outwater Double Star Caster Insert (1 Inch)
These steel threaded inserts are designed for square legs and provide a deep setting that stays secure. They feature a 3/8-16 thread commonly used with corresponding casters and flush fittings for a clean finish. They fit 1 inch square tubing across multiple gauges (16–18 gauge).
Magic Hub Star Type Insert (1″)
4-pack threaded star-type square tubing inserts with 1/4-20 threads. They fit 1″ outer-diameter tubing with 16/18 gauge walls and are designed to insert inside steel tubular legs. The zinc-plated finish helps resist corrosion and wear in general-use applications.
Magic Hub Square Tubing Star Type Insert (1″)
This 4-pack features star-type inserts for square tubing with a 1″ outside diameter and 16/18 gauge walls. It includes a zinc-plated finish and is designed to insert inside steel legs, offering a robust connection for furniture frames and similar builds.
Magic Hub Threaded Square Tubing Insert (1-1/4″)
4-pack threaded star-type square tubing inserts with 1/4-20 threads for 1-1/4″ outer-diameter tubing. The set is zinc-plated for durability and corrosion resistance, designed to insert inside steel legs to provide strong, reliable connections.
Magic Hub 1″ Square Tubing Inserts (8 Pack)
This 8-pack provides threaded star-type inserts for 1″ square tubing with 1/4-20 threads. They fit tubing walls of 16/18 gauge and are designed to be inserted into steel legs, offering a durable and unobtrusive fastener solution for frames and supports.
Buying Guide: Key Considerations When Selecting Square Tubing Threaded Inserts
- Tube size compatibility: Confirm the outer diameter and wall thickness of your tubing. Inserts come in various OD options (1″, 1-1/4″, 1-1/2″, 19 mm) and are designed to fit specific wall thickness ranges.
- Thread type and size: Common threads like 1/4-20 or 3/8-16 match standard screws and casters. Ensure the thread matches your fasteners for a secure connection.
- Connection style: Decide between star-type inserts (for stronger grip inside hollow tubing) and traditional threaded inserts. Star-type designs often offer better load distribution and retention.
- Material and finish: Zinc-plated or steel inserts resist corrosion and wear. For outdoor or high-moisture use, consider stainless steel options if available.
- Installation method: Some inserts require pressing or tapping into square or round sections. Check installation requirements and tools needed (punch, mallet, or press).
- Load requirements: Evaluate the expected load and dynamic forces. For caster applications or structural frames, select inserts with appropriate shear and pull-out ratings.
- Quantity per project: Plan packs that cover total connections. Buying in multi-packs often reduces cost per unit and ensures uniform performance.
- Finish aesthetics: Zinc plating and exposed inserts should blend with the project’s look. Consider flush or concealed installations when appearance matters.
In summary, selecting the right square tubing threaded insert involves matching tubing size, thread spec, and load expectations with a durable finish. Star-type inserts often deliver superior grip for heavier assemblies, while standard threaded inserts are adequate for lighter connections. Always verify compatibility with your fasteners and the environment where the project will be used.