Rock Climbing Gear Part 4
Cam placed in a crack.
The final piece of gear in this series is the cam. Most trad climbers cherish their cams more than any other gear. This is partly because of the price, ~$60 for what you see here, and because of the ease at which they can be placed. When climbing there is nothing more comforting than knowing you can drop in a cam in a few seconds if needed.
So more about this great tool. The stem is made from steel cable and has a steel axle that the cam lobes (the silver and green bits) rotate around. This particular one has two axles which improve the range, or the crack size variation it can be used in. While those cam lobes look just like semi-circular slices of aluminum they are actually a logarithmic spiral. Fancy eh? The reason for that shape is so the cam generates the same outward force regardless of the position of the cams. As the cams open the normal angle contact patch of the lobe remains the same. All engineering is actuated by the trigger you can see my fingers around in the right image. Do you believe that this piece is rated for 3150 lbs?