Next Return Previous

Miller 8173 Microloc
(#1648, 2634)

Front Rear
Front Rear
Side Open for Rigging
Side Open for Rigging

Technical Details

I acquired my Miller rope grab on eBay from Dan MacMurray in 2009. I acquired another in 2017 as part of Bob Thrun's collection.

The Miller Microloc 8173 is 87 mm. tall, 75 mm. wide, and 30 mm. thick, and weighs 358 g. It consists of a hinged shell made from 2.4 mm. plated steel and a forged aluminum alloy cam. The cam face is concave, but in a direction perpendicular to the rope, an unusual arrangement. The cam has a button-head pin pressed through it, and the rear end is riveted to hold a flat washer. The head fits into a curved slot in the front plate, and the washer in the back forms a similar "head" that fits into a curved slot in the rear plate. The upper end of the front plate slot is larger to clear the button head so that the front plate can swing open. A carabiner in the cam eye will prevent the cam from swinging far enough to allow opening the device.

The front is stamped with "MICROLOC™," "an up-pointing arrow labeled with "UP," "HAUT," and "ALTO," "MILLER model 8173," and the following text:

Read, understand and follow all instructions
Failure to do so may result in injury or death
Use only 5/8" (16mm) Dia synthetic rope
Maximum capacity 310 lbs (141 Kg)
Instructions en Francais sont à l'intérieur.

The rear is stamped with "PB72773" in dot matrix font and the following text:

Meets OSHA, ANSI A1014 , Z351.9
and OSA Z259.2 .1-98
3 ft(0.9 m) Max lanyard length
Use only with locking carabiner
CE 0333 EN 353-2

The inside of the front plate is stamped with "MICROLOC™," "an up-pointing arrow labeled with "UP," "HAUT," and "ALTO," "MILLER model 8173," and the following text:

Lire attentivement les instructions d'utisation, Ne
pas les respecter peut engender des risques mortels
Utiliser uniquement un cordave de Ø 16mm (5/8")
Charge maximum de 141 Kg (310lbs)
Made in France


This is a very simple way to make a swing-open lever cam device. It works much better than the approach taken on the Gibbs Quick, and is simpler than the ones used for the Levistan or Reflex.