Pipe couplings RK10 black

Tube connectors in the RK10 series join two round tubes into one continuous length without welding. The connector is made in PA6 and is pressed into both tube ends; the result is a straight two way joint that holds the tubes in line.

PA6 is a sensible material choice for exactly this part. The nylon is tough and impact resistant, it springs during the press fit and then takes vibration and handling without cracking. The material stands up to oils and most solvents found in a workshop, and it takes up a little moisture from the air, which in practice makes the part tougher still.

Compared with a connector in a softer plastic, PA6 gives a stiffer joint. The stiffness is needed here; the connector has to do more than stay in place, it also has to hold the two tubes in a straight line when someone leans against the frame.

The series covers 25 tube dimensions, from 15 up to 60 mm outside diameter, intended for wall thicknesses from 1.0 to 2.0 mm. Roughly half the length of the connector ends up in each tube; the exact length for each dimension is given in the data sheet. The surface is matte and the color is black.

Joining without hot work is the whole point. No welding certificate, no fire watch, no paint to touch up; you cut the tubes, press in the connector and keep building. In premises where hot work needs a permit, that saves both time and paperwork.

Typical uses in Swedish industry are lighter frameworks, display stands, carts, barriers and fitting details where round tubes are built together. The connector also works when a tube has ended up a few centimeters too short; splicing on a piece goes considerably faster than ordering new material and waiting for delivery.

Another everyday use is prototype building. Designers testing a frame in the workshop can recut and move joints several times in one afternoon, without booking the welder between each round; once the geometry is settled, the final structure can be welded or bolted.

In looks, the black matte surface blends in against both painted and bare tubes. The joint is visible of course, but it looks deliberate, rather like a sleeve, and it does not rub off or leave marks during handling.

Mount it like this: cut the tube ends straight, deburr them on the inside and then press in the connector by hand or with a rubber mallet until the tubes meet in the middle. A straight cut is everything. Ends cut at an angle give a joint that looks kinked no matter how well the connector sits.

The choice of dimension is governed by outside diameter and wall thickness together. A tube with a 16 mm outside diameter and a 1.0 mm wall has a different inside diameter than one with a 1.5 mm wall, and it is the inside diameter the connector has to fill. So measure both dimensions with a caliper on the actual tube; tube that has been in the store for a while can be something other than what the label claims.

Keep in mind at the same time that the joint is mechanical and not load bearing in the same way as a welded seam. For frames, racks and fittings it is plenty; for load bearing structures with point loads you should reinforce with a through bolt or choose another type of joint.

You pick the dimension as a variant on the product page. As simple as it sounds.

Do you have a specific application in mind? We will gladly help you choose the right connector.