Front	Rear

Top	Open for Rigging

Technical Details

I started making my Bat Climber around 1980, but did not finish it until 2004.

My Bat Climber is 52 mm. tall, 156 mm. wide, 42 mm. thick, and weighs 239 g. The side plates are 3.3 mm.6061-T6 aluminum, and the cams are cut from 12.7 mm. 6061-T6. One cam axle is made from a 7/16" UNC bolt secured with a lock nut, the other is 3/8" (9 mm.) and is secured with a hitch pin.

Comments

Jack Speece described the Bat Climber in 1968 (Shippensburg Grotto Newsletter, v. 3, 3), and Bob Thrun devoted a few sentences to them in his book Prusiking. I eye-balled my version from the drawing in Bob’s book, but instead of putting a straight toothed cam surface, I used a smooth circular one - for no other reason than I haven't gotten around to milling teeth. Jack & Bob note that the Bat climber has no advantage over a single-cam climber like the later Gibbs. Mine, frankly, is a lemon, but part of the reason is the cam angle that I used. Since the two cams rotate independently, the original Bat Climbers had a safety pin on each side to keep one cam from closing before the other. I didn't put a safety catch on mine, and it is practically impossible to get the cams to close simultaneously. Interestingly, this is why mine actually hold - the sharp nose at the bottom of the first cam to close digs into the rope, providing enough friction to get the ascender to hold. Maybe if I sharpen this nose, it will cut the rope in two, and you won't have to put up with any more of my bad jokes.

At some time I might make a more faithful copy of the original to see how it works, but until then, I'll leave this one in the collection box.