End Face Connector for Aluminium Profile M8 M10 up to 50 mm Series with Spring Clip

The spring clip is an assembly aid, not a structural part

Take the clip off and the connector still works — it will carry exactly the same load. What changes is how hard the frame is to build. Without the clip, the bolt sits loose in the core bore of the member and falls back out of reach as soon as you let go of it. You need one hand to hold the member, one to hold the bolt and one to start the thread, and most people do not have three.

The clip clips onto the connector and presses against the inside of the core bore, which holds the bolt at the mouth of the hole. The member can then be offered up to its neighbour and the bolt started with one hand. It also centres the connector in the bore, so the thread goes in straight rather than cross-threaded. On a frame with dozens of joints that is the difference between an hour and an afternoon.

End connector or anchor connector?

Both connectors fix into the end of a profile and both give a hidden joint, so they are often confused. The difference is the mechanism, and the mechanism decides how you assemble and disassemble the frame.

The practical rule is about access. If you can reach the end of the member and you want the frame to come apart again, use the end connector. If the end is inaccessible but a side face is open, the anchor connector becomes attractive. If neither end nor side is accessible, you are looking at a bracket or an inner bracket instead — see the anchor connectors range for the alternative.

The end face has to be square, and the error multiplies

An end connector seats on the end face of the member. If that face is not square to the axis of the profile, the whole member is tilted, and the tilt grows with distance. The relationship is simple: the deviation at the far end equals the end face error multiplied by the length of the member and divided by the width of the section.

Put numbers into it and the size of the problem becomes clear. A 0.1 mm squareness error on a 40 mm wide section is a slope of 1 in 400. Over a 2 m member that is a 5 mm deviation at the far end — five millimetres, from a tenth of a millimetre of saw error.

Two conclusions follow. First, the end face has to be machined, not just cut. A saw cut is typically square to within a few tenths of a millimetre; an end face connector joint wants the end faced on a machine to better than 0.1 mm. Second, the wider the section, the less the error is amplified, because the denominator in the formula is the section width. That is one more reason a large section is more forgiving than a small one.

Assembling an end face joint

1. Face and tap the ends as a pair Cut, face and tap both ends of each member in one setup. Tapping to a depth of at least 1.5 times the bolt diameter gives full thread strength.
2. Fit the clip to the connector and push it into the bore The clip holds the bolt at the mouth of the hole. Check it is seated squarely before offering the member up.
3. Bring the members together and start the thread by hand Start the bolt by hand for the first two turns. If it does not go in freely, the members are not aligned — do not force it.
4. Tighten in a sequence, not one at a time On a multi-bolt joint bring all the bolts up to half torque first, then finish them. Tightening one bolt fully before starting the next pulls the joint out of square.
5. Check the frame diagonals before final torque Once the bolts are tight the geometry is fixed. Check the diagonals with the bolts just nipped up, and adjust before finishing.

Frequently asked questions