Needing a block and tackle for my kid’s tree fort I didn’t want to go overboard with some store bought mechanism although with a bit of shopping you can find them fairly cheap. All I needed was something light duty and simple – I did try to make a double pulley similar to my antique set, but I had problems getting the double side-by-side pulley to sit perfectly balanced. Then I had the idea to keep it really simple with all the pulleys in one plane so this is what I came up with. This is not a complicated project by any means, I was surprised at how easy it was to make and can easily be manipulated (bigger/smaller pulleys, heavy duty materials, etc.) to make something really interesting. It works well and holds more weight than you would need – I used 1/16” aluminum which has a tensile strength far higher than anything my kids will haul and the #8 bolts will ensure that their arms or interest give out long before the B&T does!
Materials are plywood, sheet aluminum, nuts and bolts, and a couple inches of half inch straight copper tubing. I used simple hand tools and an electric drill and had them put together in about 4 hours worth of time.
Step 1: Pulleys and plates
First thing is the pulleys - depending on what kind of system you want (2/1 or 3/1 or 4/1 . . .) you need that amount of pulleys. I decided that my plates were long enough to make a four-to-one system so I made four - this means that hauling a 100 pound load will actually be 25 pounds on the rope that I am pulling. Pretty cool. Yes, I am easily impressed. I used a hole saw to cut out my discs (keep in mind they can't be the same size or you will have interferance with the rope as they run around the pulleys) and then used the drill as a lathe with a round or rat-tail file to form the groove for the rope. A bolt through the disc can be chucked in your drill to hold it. It took me about 5 minutes for each disc. The aluminum plate I cut out from some angle plates I had, labeling them 1 and 2 as to not confuse them. The last shot shows both discs with the rope around them - I grooved it deep enough that 3/4 of the rope sits below the outside edge of the pulley. They could be deeper if you are a belt and suspenders type person.