Front	Rear	Top
Left	Right	Bottom

Pin installed (for 8.4-9.7 mm. rope)

Front	Rear	Top
Left	Right	Bottom

Pin removed (for 9.8-11 mm. rope)

Technical Details

I acquired two Mad Rock Mad Locks from Mad Rock in 2009.

The Mad Lock is made from a stamped aluminum frame, a stamped aluminum rope channel, and two pins. The frame is an irregular stamping with one large hole below the rope channels and a hooked opening to the side. The rope channels are formed by a second U-shaped stamping. The center of the U is notched so that won't wobble on the frame. The ends are closed by a rivet that passes through the channel piece, a rope block, the frame, a second rope block, and the other end of the channel piece. A second, removable pin passes parallel to the first, and is held in place by a machine screw. The end of this pin has two milled flats and the hole in the side stamping is shaped to match, so the pin cannot rotate.

The removable pin should be installed when using ropes with diameters between 8.4 and 9.2 mm. In this configuration (e.g., the red one in the photos), The Mad Rock Mad Lock is 45 mm. thick, and weighs 79 g. The rope channel is 32.8 mm. long with the pin removed.

The central rib is stamped "MADROCK" and printed with an arrow pointing to the words "Pull for less friction," "PAT.PEND." and "IE1." One side of the shell has a printed rigging illustration, the other is printed with "Read instruction," "8.4-9.7 mm" (by the hole for the removable pin), and "9.8-11 mm" (by the fixed pins).

Comments

Rig the Mad Lock by inserting a bight (single rope) or bights (double rope) in from the top (as shown on the diagram on the device) and clipping an HMS carabiner through the bight(s) and the large hole in the central plate. Make sure that the standing rope going to the belayee comes out on the side with the hook, and that the free end comes out over the fixed pin(s). Rappelling is done the same way.