Pipe coupling RK22 34 mm, matte gray

Plastic tube connectors work as a building system for anyone designing frames, workbenches, carts, machine guards and railings from standard tube. Instead of welding every joint you pick a connector with the right number of connections and assemble the structure like a kit. It goes faster than welding, and the structure can be changed afterwards: a leg can be moved, a shelf can be added and a damaged section can be replaced without taking the rest apart.

Planning is half the job. Draw the structure, count the joints and note which connector type each point needs; only then do you cut the tubes, since the connectors add a few millimeters per connection. A good tip is to dry assemble the whole frame loosely before the parts are tapped fully together, so that you have time to adjust cut lengths while it is still easy to pull apart.

The connector is molded in one piece in PA6 without metal reinforcement. That keeps the weight down and is plenty for shelves, racks and fittings where the joint is mainly held together by the stiffness of the tubes themselves. If you need to bolt the structure to floor or wall, or hang a load directly in the joint, there are sister versions with a molded in steel core and an internal thread in the same range.

PA6 is a tough engineering plastic that damps knocks and vibration better than an all metal joint. The surface is matte gray and colored all the way through, so scratches and marks from assembly are barely visible. The material handles oils, greases and normal cleaning agents, and for natural reasons it never rusts; in damp premises and wash bays that is a heavier argument than you first think. Unlike welded joints there are no sharp weld spatter or burrs to hurt yourself on here, and the rounded shape of the connector is kind to both hands and goods passing close by.

We see the connectors in workshops that build fixtures and material racks, at store fitters who assemble display stands and in maintenance departments that quickly need to repair or rebuild existing tube structures. Since assembly only calls for a cut off saw and a mallet, even someone without a welding certificate can build stable structures from steel tube, and the result looks well made without grinding or painting.

Dimensions and detail drawings are in the manufacturer's data sheet. If you need more connector types for the same build, you will find the whole tube connector program under the Fasteners category here in the web shop, with two way to six way connections for both round and square tubes. The tubes themselves you buy as usual as structural steel tube; the connectors are dimensioned to the standard sizes normally used for welded and cold formed tube.

With RK22 you build tube structures together without welding. The connector is a hinged two way connector for square tubes in nylon PA6, made for square tube 20x20 mm with a wall thickness of 2.0 mm; you cut the tubes to length, put the connector in and tap the parts together with a rubber mallet. No welding certificate, no surface finishing afterwards, no special tools.

This connector has a total length of 34 mm. Check both the outside dimension and the wall thickness of the tube before you order; the press fit relies on the inside dimension of the tube, and a tube with a different wall thickness gives either play or a connector that cannot be driven fully home. The hinged design lets the angle between the tubes be set, which is practical for angled braces and builds that are not square.

Questions about dimensions or fit? Call us and we will sort it out before you order.