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M-LAB

About

Better replacement parts for everyday products

M-LAB designs the small parts that break first and make a good product useless. We start with the part that fails, figure out why, and engineer a version that fits right and holds up. First up: the end caps that keep your camp chair’s bungee in place.

Step 1

Find the failure

Every part starts as a broken one. This is the cap that started it: the head torn away at the shoulder, where the shock cord pulls hardest and the original has the least material.

A failed black original-equipment camp chair end cap: the head has broken away leaving a jagged torn edge and a loose shred of plastic, with the shock cord still threaded through it

Once the shoulder lets go, the head cannot seat on the tube end any more and the cord pulls the cap down inside the leg. The tube end is left bare, the cord loses its anchor, and a chair that is otherwise fine ends up in the garbage.

Most of what we know came in the post. People send us the cap that failed, and we have replaced them on chairs from REI, Helinox, Cascade Mountain, Wildhorn Terralite, Parks Project and Trekology, among others. The size is set by the tube rather than the maker, though — even one brand ships chairs with different tube diameters — so it is still worth measuring yours.

Step 2

Redesign the part

Model it, print it, fit it to a real chair, then change what did not work and do it again.

Fusion 360 render of two M-LAB end caps with domed heads. The left one is cut away lengthways to show the hollow bore and the slot the shock cord passes through, with M-LAB embossed along the body. The right one is whole, with the size 11 marked on the side.
The current cap in CAD — cut away to show the bore and the cord slot, and whole with the size on the body. Not a dimensioned drawing.
How the M-LAB end cap worksCutaway of a chair tube with the end cap pressed in and the shock cord anchored in the cap. Head diameter is size plus 4 mm; the body matches the tube's inside diameter; caps are 27.5 mm long. How the end cap worksCutaway view, 10 mm cap shown.27.5Head Ø = size + 4 mmStops against the tube end and takes the cord load.Body Ø = pole inside ØMatches the bore; the cord holds the cap in.Cord anchorThe shock cord is tied off inside the cap.Tube wallYour chair’s tube. Measure its inside diameter.Schematic. Internal cord path simplified.

Three changes came out of that, and together they are why the cap is engineered to last longer than the original: a thicker shoulder where the original cracks first, a tougher material, and a rounded head in place of the original’s flat end, which tested better in most chairs.

Step 3

Make it, in sizes that actually fit

Eight sizes rather than one compromise, because a press fit only works if it is the right diameter.

A single-storey business unit in El Dorado Hills with M-LAB lettered on the glass door of suite 5, a tree and low hedge out front
Suite 5, El Dorado Hills. Everything is made and packed here.
A build plate covered in rows of finished black M-LAB end caps, still attached after a print run
One build plate, straight off the machine.

Engineered in the USA.

Earlier revisions

How the cap changed

The first version ended in a flat disc. The shipping cap has a rounded head and more material at the shoulder, which is where the original cracks and where ours has to not.

An earlier flat-headed revision of the end cap with a bungee cord knotted inside its side slot
An earlier revision. The shipping cap has a domed head.
Two end caps from an earlier revision, shown with flat disc heads and open side slots
An earlier revision.

Next

More camp chair parts to come

The end caps are the first part, not the last. We are working through the other pieces of a camp chair that fail early. No promises on specific parts or dates yet.

Broken something we should engineer? Tell us →

Two people sitting in low packable camp chairs either side of a small campfire in a pine forest, holding mugs