Pipe couplings RK15 black

RK15 is a straight two way connector with a steel core for round tubes in nylon PA6. The series covers round tubes from 16 to 60 mm outside diameter with a wall thickness from 1.0 to 2.0 mm, 23 versions in total, and you pick the dimension as a variant here on the product page. The connector is pressed into the tube ends and builds the structure together without welding; cut the tubes, put the connector in and tap the parts together with a rubber mallet.

The idea behind the tube connector system is simple. Every joint in a frame, a workbench, a cart or a machine guard gets a connector with the right number of connections, and the whole structure is assembled as a kit from cut standard tube. It calls for neither a welding certificate nor surface finishing, and the build can be changed when the needs change: a leg is moved, a section is replaced, a shelf is added without taking the rest apart.

A straight two way connector is used to join tubes lengthwise or to link straight sections in railings and handrails. With a range from 16 to 60 mm the series covers most things from thin pull handles to heavy frame tubes, and the same connector type can come back through the whole structure.

Work through the build before you order. Every joint adds a few millimeters per connection, so the cut lengths are set after the connector types are chosen, not before. Dry assemble the frame loosely before the parts are tapped together; that gives you time to adjust a cut length or change a connector type while the structure can still be pulled apart without tools. Write a simple pick list per joint while you are at it, that makes both ordering and assembly faster.

Inside every connector sits a molded in core of zinc plated steel. The core makes the joint considerably stiffer than a connector made entirely of plastic and lets it take up larger moments; that shows in tall racks, long unbroken tube lengths and structures that are moved often. On the outside the connector looks like its all plastic siblings, with the same matte surface and the same simple assembly.

PA6 is a tough engineering plastic that damps knocks and vibration better than all metal joints. The surface is matte black and colored all the way through; scratches from assembly and moving are barely visible. The material handles oils, greases and normal cleaning agents and never rusts, which makes the connectors useful even in wash bays, commercial kitchens and other damp environments where painted or welded joints quickly look worn. The plastic also insulates both electrically and thermally, so the joints are neither cold to touch nor conductive, a detail that is appreciated in handles and railings.

Choose the version by the outside dimension and wall thickness of the tube. The press fit relies on the inside dimension of the tube, so two tubes with the same outside dimension but different wall thickness call for different versions; measure with a caliper if you are unsure and check against the dimensions in the manufacturer's data sheet. The variant list here on the page shows exactly which combinations the series covers, so you never have to guess. Tube in ordinary structural steel, stainless or aluminum works just as well; it is the dimensions that govern, not the tube material.

We see the connectors in workshops that build fixtures and material racks, at store fitters who assemble display stands and in maintenance departments that repair or rebuild existing tube structures. Feel free to combine several connector types from the same program; the whole range of tube connectors, from straight joints to six way joints, is in the Fasteners category here in the web shop. Many builds mix all plastic connectors in lightly loaded points with steel core reinforced ones in the load carrying points, so that cost and stiffness end up where they do good.

Do you want to talk the structure through before you order? Get in touch and we will help you work out the joints.