Introduction: Foldable Grappling Hook for Harvesting Spam
... spam signs, that is. Vertical litter.
I've been wanting to remove a number of unsightly and illegal signs from trees and utility poles around here. However, I need to be able to reach them and I'd like to do it from my bike.
So I made this foldable grappling hook to tear down the signs.
This instructable will show you how I did it.
Warning: THIS IS NOT SAFE TO CLIMB WITH! IN FACT, DON'T EVEN PULL HARD ON IT! This wasn't designed with safety in mind; it was designed to pull down plastic signs. DO NOT TRUST IT WITH YOUR SAFETY!
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Step 1: Gather the Parts
I built this out of parts that were available at my local hardware store.
1 - 3 foot long (48 inch) piece of 3/8 inch aluminum rod stock
3 - 1 foot long pieces of 3/16 inch vinyl coated cable
3 - 1 foot long pieces of 3/32 inch vinyl coated cable
9 - wire rope clamps that will go around the 3/8 inch rod stock and one piece of 3/16 cable
1 - snap clip
1 - ring (I used one that screws closed, but that isn't necessary)
20 feet of nylon line, with the cut ends fused using a flame so they don't fray
Step 2: Make the Hooks
I made the hooks from a 3 foot (48 inch) long piece of 3/8 inch aluminum rod stock.
First, I used a hacksaw to cut the rod into 3 equal lengths 16 inches long. I used a file to smooth the sharp edges.
Then I used a vise to hold the rods near where I wanted to bend them, and bent them by hand.
I put bends in at about 4 inches and 3 inches from either end.
Step 3: Assemble the Parts
Everything here just screws together, held by the wire rope clamps. Make sure that you get the nuts on these clamps really tight! I found that a nutdriver wasn't enough; I ended up using a 1/2 inch open end wrench to do the final tightening.
It'll be easiest to clamp the 3/16 (fat) cable pieces to the hooks first, making sure that any curve in the cable is facing the same way with respect to the hook. Then attach the other ends to the ring using three more clamps.
The small cable pieces are clamped (two ends at a time) to the hooks so that they keep the hooks from spreading when under load. See the photos.
The snap ring should be attached to the nylon line. I used a bowline knot; two half hitches or similar should also work.
I found that it was easiest to hang the hook from the nylon line (attached to an overhead object) to do the final adjustment. You'll probably have to loosen the clamps and twist things around to ensure that the hook opens evenly with all the hooks facing outward at the right angle. Then tighten the clamps really well!
I also found that a rubber band attached loosely around the cable near the hooks helped the form of the hook when it was opened. Experiment to see what works best for you.
Step 4: Fold the Hook
Because the hook is joined by wire rope, it can be folded into a compact package.
I used a "One Wrap" (hooks on one side, loops on the other) Velcro strap to hold the hook closed.
Just fold the hooks over until they're all facing the same way, and tighten the strap.
Step 5: Make a Carrying Box From Spam Signs
This will be the subject of a separate Instructable, but I thought you might like to see what I am carrying this hook with when I go on my sign-harvesting forays.
I made this box from a single 18 x 24 inch sign that I removed from a tree in the neighborhood. Just score one side at the bends, bend, and use Gorilla Tape to reinforce the bends and edges.
You could use duct tape, but it won't be as strong or last as long as Gorilla Tape.
The door is held closed by a tape flap and a piece of Velcro.
The box is attached to the bike luggage rack by another two pieces of industrial-strength Velcro (I had to tape down a couple of small pieces of sign first to build up the height of the underside surface so the Velcro would reach down to the Velcro on the rack).
Step 6: Go Harvest Some Spam!
Now get out there and beautify your neighborhood!
The second image in this step is a PDF file that I print out, laminate, and attach to trees and poles that I have cleaned of spam if they had lots of signs on them.
For more information on sign spam, please see http://www.causs.org
Happy spam harvesting!