Step 1: Obtain Parts
1 2"x1/2" Mending Brace
2 1"x1/2" Corner Braces
2 Hose Clamps of appropriate size for the upper shaft of your trekking pole (smaller the better)
Some Gasket Material (I found this rubbery pipe mending stuff in my closet, but I imagine an old bicycle tire inner-tube would work well)
1 3/4" long Screw
1 3/4" long Thumb Screw
2 Lock Nuts
6 or more Nylon Washers
All Screws, Nuts and Washers are 1/4"x20 thread.
Step 2: Assemble
Start by attaching the three braces as shown with the non-thumb screw, four nylon washers, and a lock nut. Don't tighten the lock nut all the way down. Leave it loose enough that you can rotate the mending brace, but tight enough that it will stay where you put it.
Next, attach the thumb screw to the other hole of the mending brace with the other lock nut and at least one washer on either side of the brace. Orient the screw so it is facing the opposite direction of the first screw, unlike in the photo (so that the first screw doesn't get in the way of the camera). Tighten similarly.
Step 3: Mount
Next, slide a hose clamp all the way up to the handle, then place the mount against the gasket stuff so that the mount is sticking out on the left (right if you're left handed) side of the handle (from a 1st person perspective), place one of the gasket pieces over the top flange, slide the hose clamp over it, and tighten just enough to get it to stay. Repeat for the lower half and adjust until the mount is in the right spot. Now tighten the hose clamps the rest of the way, but not so tight that you risk denting your trekking pole.
Mount your camera, loosen/tighten the lock nuts to taste, and you're done!
Step 4: Use
Admittedly this project isn't perfect compared to a real monopod. The mount is slightly wobbly when taking photos one-handed and there is no mechanism for tilt or pan. Still, my pictures are remarkably crisper using the monopod with both hands vs. freehand, especially with longer exposures. Also, since my camera is very light, I can drive the pole into the ground at slight angles if necessary.
Anyhoo, I hope you've enjoyed my first instructable. Happy shooting!