Step 1: Determine the Length of Pull of Your Generator
It is important to know how much cord is available so that you don't rip the cord off the machine. For this project, it was determined that there was about 50 inches of cord. The author planned to use 4 wraps of the pulleys with about 12 inches of pedal travel.
4 wrap x 12 in travel = 48 total inches of travel.
Step 2: Get hole saw to make the pulley
A hole saw to cut a disk from a Corian countertop scraps. They are about 1/2 inches thick. Four were cut for this project.
Step 3: Turn a Groove in the Pulleys
Use a lathe to put a groove in the edge of the pulleys so the rope would stay in. The author bored out the 1/4v hole to 3/8 with a 3/8 inches drill bit.
Step 4: Cut the 2x4 to Two 48 inches Pieces
If starting with an 8 foot long board, you can get two pieces 47-15/16, but that should be close enough.
Step 5: Locate the Hole for the Pulley and Drill
The holes were located about 1.25v in from the end and 1/2 inches from the bottom edge of the 2x4. This gives more material for pushing down on the axle bolt for the pulleys. The author wanted the board to press down on the axle bolt than pulling it down and splitting the grain of the board. The location of the hole by hitting the bolt with a hammer was marked. Then the center was punched and a hole was drilled it clear through the 2x4. A LONG drill bit is needed. Alternately, the hole can be marked and drilled from both sides, but that is harder.
Step 6: Mark the Pedal Board where the Pulleys Go
Washers were stacked in between the pulleys to figure out how wide the notch needed to be. Then the edges of the pulley were traced on the board to aid as a guide to cut.
Step 7: Use Jigsaw to Cut Slot for Pulleys
Step 8: Countersink the Bolt Head and Nut
A hole measuring 1 inches in diameter about 1/2 inches deep on both sides was drilled in the board. This had to be done so the bolt would not rub when the pedal moves.
Step 9: Bolt the Pulleys and Washers into the Pedal
Then a washer on each side of the pulleys was inserted to keep them from rubbing against each other. This would make them harder to turn. A nylock (nylon insert lock nut) is used to keep it from coming apart. The bolt should not be too tight or the fork will squeeze the pulleys and make them hard to turn.
Step 10: Measure the Travel to Figure out How long the Boards Should be and Cut
Although 18 inches is probably a good length it is good to know where this comes from. The author wanted 12 inches of travel so we put the board with the pulleys against the bottom frame piece (the other 48 inhces board) and marked the "start of travel." Then we swung the pedal up and marked where it moved 12 inches. Then we added about 2 inches for the pulley. All of this added up to about 18 inches.
Step 11: Mark the Upright Pieces and Drill the Pulley Bolt Holes
Each of the 18 inches uprights will have a 3/8 inches hole drilled in them to support the other set of pulleys. We put these holes closer to the edge of the board so that when force would be applied to them more wood would be in compression than tension. The first one was marked with the bolt, center-punched, and drilled. We use the first one as a template to locate the bolt hole for the second upright. The bolt was hit with a hammer to transfer a mark to the second upright. Then that upright was drilled. This way we knew for sure that the bolt holes would line up.
Step 12: Bolt the Hinge onto the Base Board
The "Base Board" is the 48 inches 2x4 that doesn't have a pulley bolted to it. It gets a hinge in this step. We traced the hinge to make sure it didn't move while we bolted it on. Then we drilled pilot holes for the 1/4 inches bolts. A washer goes under each bolt head. The 1/4 x 1.5 inches lag bolts we used to hold the hinge on. If you use a different style of hinge you may have to use flat head screws instead of hex heads like we used.
Step 13: Put in One Bolt on the Pedal to Line up the Hinge
The author laid the pedal board on top and traced the hinge for reference as well as we could. Then the author swung the pedal all the way up so we could put ONE bolt in the center of our hinge. We drilled a pilot hole for one of the 1/4 inches lag bolts and tightened it. Then we swung the pedal back down against the other board and moved it side-to-side to twist the hinge so both boards would be lined up against each other when the pedal was all the way down.
Step 14: Complete Bolting the Pedal Hinge Down
CAREFULLY, swing the pedal back up WITHOUT MOVING THE HINGE. Then mark the holes. Next, center-punch the holes and drill pilot holes for the remaining bolt. Next, bolt the hinge to the pedal.
Step 15: Make a Set of Gussets for the Uprights
A set of gussets is needed for the uprights. These can be any triangle shaped piece of plywood or OSB. Then the author cut in triangles and THEN realized the pedal would hit them on its travel downward. Next, put a set of guide strips on our uprights to keep the pedal from getting stuck on the gussets. An improvement on this step would be to trace the uprights on your gussets and include the guide strip in them as one piece. You might even be able to get away with NO uprights and just the gussets if they are made of thicker material and made 18 inches tall.
Step 16: Screw Gussets and Guide Strips to the Uprights
The author made a set of guide strips from some scrap material the same thickness as our gussets (again, you could integrate your side strips into the gussets as one piece if you like). A pilot hole was drilled and screwed upright to make two mirror image pieces. Note that the bolt holes are one the far edge of the boards from the pedal.
Step 17: Screw the Uprights to the Base Board
For this step, four 1-5/8 inches drywall screws and one 3 inches drywall screw to attach each of the uprights to the base board.
Step 18: Countersink the Bolt Head and Nut (if needed)
The pulley that bolts to the upright portion needs to be placed. The longest bolt we had was about 8v instead of the 9 inches I would have liked. We use a 1 inch spade bit to countersink the head and the place where the nut would go because of our short bolt.
Step 19: Cut PVP Pipe Bushings to Center the Pulleys
3/8 inches PVC pipe kicking was used to make a set of bushings. This centered the top set of pulleys so they don't wander. We put the pulleys and three washers through the uprights temporarily. Then we measure the gap we had to fill. Then we marked two pieces of PVC to fill this gap. Our pulleys were 1/2 inches thick (same as our plywood). We needed to fill about 3.5 inches so we cut the two pieces 1.75 inches long.
Step 20: Bolt the Pulleys on and Put a Rope on it
The pulleys were bolted on and then it was time for the rope. The rope was threaded through each of the pulleys starting by going from the hinge end. We went over the top of the first pulley. Then the rope goes around each of the other three. We tied our rope off on the bushing on top pulleys with a bowline so it wouldn't slip. Then we used the propane torch to cut and fuse the braided rope at the same time. We tied an additional bowline in the other end to put the pull start tee handle through. Note: We later untied the rope from the top bolt and tied it to the bottom pulley to change the ratio from 4-to-1 to 3-to-1. This makes it a little easier to start the generator.
Step 21: Ready to Test!
After the rope was tied, it was ready to test. The author recommends the motion of climbing a flight of stairs to operate. This started the engine very easily on the first time. I did reduce the ratio from 4-to-1 to 3-to-1 by tying the rope to the bottom pulley instead of the bushing. It works in that capacity as well, even though it reduces the travel to 36 inches.
Author: yeltrow