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I acquired my Macrograb from On Rope 1 in September, 2000.
The Macrograb looks and functions like a Type 1 Lever Cam Ascender, but it is marketed as a rope grab. The frame is milled from aluminum (much like the Rock Exotica ascenders). The rectangular-shaped rope channel is 20-mm wide. The inside of the shell has a milled depression that the cam forces the rope into. This spreads the load on the rope, and may increase the holding power of the ascender. It is claimed to help reduce rope damage under shock loading, but I can't confirm this. Rock Exotica pioneered this feature, and Petzl acquired it from them.
The cam has 5 rounded teeth, and is held by a cable keeper that doubles as a spring that applies a significant closing force to the cam. The keeper is attached to the cam by a small set screw. The cam axle is an 8-mm Allen-head cap screw secured with a locknut. The top of the rope channel is rounded off so that the rope does not bend over any sharp corners. In addition to the axle hole, the frame has three small holes. One is for the keeper, and a second, drilled from the side, accepts an set screw to hold the keeper in place. The third hole, through the back of the frame, does not serve any obvious purpose.
The front of the frame is stamped with an arrow pointing up, the Petzl logo, "12<Ø<19mm," "1/2"<Ø<3/4"," "EN567," "CE 0197," an icon showing how to rig the cam, and Petzl's "reading is dangerous" icon. The rear of the frame is stamped with "001966" which I assume is a serial number or date code. The frame spine is stamped with "USE ONLY APPROVED 12"-3/4" (12-19mm) SYNTHETIC ROPES," "CHECK UNIT BEFORE EACH USE," and "REMOVE FROM SERVICE AFTER SUBJECTED TO LOAD OR FALL." The rear of the cam has an arrow stamped on it, I don't know what it intends to show.
The Macrograb is a clunky-looking device. Its a shame that Petzl couldn't round the inside of the rope channel, after all, most of us use round ropes instead of square ones. The cap screw axle is a cheap way to mount the cam, and it makes it excessively difficult to put the Macrograb on rope or take it off. Petzl supplied a 5-mm Allen wrench for the cap screw but forgot to provide a wrench for the nut. This is rather surprising, since they included a 2.5-mm Allen wrench to remove the two screw holding the cable to the cam and frame! It really doesn't matter, most people will quickly lose both Allen wrenches.
The minimum rope size specified for the Macrograb means that it will only be of interest to the "bigger is better" crowd. They are welcome to it.
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I acquired my Micrograb from On Rope 1 in September, 2000.
The Micrograb is a smaller version of the Macrograb. The frame is milled from aluminum. The rectangular-shaped rope channel is 15.7-mm wide. The inside of the shell has a milled depression that the cam forces the rope into. This spreads the load on the rope, and may increase the holding power of the ascender. It is claimed to help reduce rope damage under shock loading, but I can't confirm this. Rock Exotica pioneered this feature, and Petzl acquired it from them.
The cam has 8 rounded teeth, and is held in place by a cable keeper that doubles as a spring that applies a moderate closing force to the cam. The keeper is attached to the cam by a small set screw. The cam axle is an 8-mm Allen-head cap screw secured with a locknut. The top of the rope channel is rounded off so that the rope does not bend over any sharp corners. In addition to the axle hole, the frame has two small holes. One is for the keeper, and a second, drilled from the side, accepts an Allen screw to hold the keeper in place.
The front of the frame is stamped with an arrow pointing up, "EN567," "9<Ø<13mm, "3/8"<Ø<1/2"," "CE 0197," an icon showing how to rig the cam,the Petzl logo, and Petzl's "reading is dangerous" icon. The rear of the frame is stamped with "00175L" which I assume is a serial number or date code.
The Micrograb is another clunky-looking device. Its a shame that Petzl couldn't round the inside of the rope channel, after all, most of us use round ropes instead of square ones. The cap screw axle is a cheap way to mount the cam, and it makes it excessively difficult to put the Macrograb on rope or take it off. Petzl supplied a 5-mm Allen wrench for the cap screw but forgot to provide a wrench for the nut. Things are even more hilarious than on the Macrograb: the cam set screw requires a 2-mm Allen wrench while the frame set screw requires a 1.5-mm wrench. In all, three wrenches are provided to be lost at the first opportunity.
I suggest that anyone seriously considering the Petzl Micrograb look at the PMI Grip-Tech Jr. before committing themselves.
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©2007, Gary D. Storrick