Threaded Tube Ends

Measure the inside diameter (round) or inside width (square) of your tubing at the end where the insert will be installed. This is the dimension that must match the insert's outside profile for a proper press-fit. Do not rely on the nominal tubing size stamped on the material, as actual inside dimensions vary depending on wall thickness.

We stock threaded tube ends with internal threads in the most common caster stem sizes including 3/8"-16, 1/2"-13, 5/8"-11, and other standard configurations. Metric thread options may also be available depending on the model. Check individual product listings for the full range of thread sizes offered.

Yes, when properly sized and installed. The load capacity depends on the insert material, the wall thickness of your tubing, and the thread engagement between the insert and caster stem. Steel and reinforced nylon inserts in heavy-wall tubing can support substantial loads. Always confirm the rated capacity of the insert meets or exceeds your per-caster load requirement.

Most threaded tube ends are press-fit inserts that you tap into the open end of the tubing with a rubber mallet. The insert's ridged or barbed exterior grips the inside wall of the tube to resist pull-out. Some models include an expansion feature that tightens as the caster stem is threaded in, further securing the insert. No welding, adhesive, or special tools are needed.

Caster Central carries threaded tube end inserts for both round and square tubing in the most common dimensions used for cart frames, shelving units, workbenches, and custom material handling equipment. Round inserts are sized by outside diameter to match standard tubing from 3/4" through 2" OD. Square inserts correspond to common square tube sizes from 3/4" through 2" across. Internal thread options cover standard caster stem threads including 3/8"-16, 1/2"-13, and 5/8"-11 among others.

Proper sizing requires two measurements. First, measure the inside dimension of your tubing at the end where the insert will be installed. The insert's outside profile must fit snugly inside the tube. Second, confirm the thread size of your caster stem. The insert's internal thread must match the stem's external thread exactly. A mismatched thread will either prevent installation or create a loose, unsafe connection. For gauge-wall tubing where inside dimensions vary, measure carefully rather than relying on nominal tube size alone.