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Picture of Make a light-duty block and tackle
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.
 
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Step 1: Pulleys and plates

Picture of Pulleys and plates
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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.

Step 2: Drilling the plates

Picture of Drilling the plates
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There are two sets of two plates - one has 4 holes and the other 3.  The most important aspect is getting the holes in both plates to be aligned to each other.  This is pretty easy as all you have to do is clamp them together and drill the pilot holes through both at the same time.  Then, as you step drill each one separately to size, your original holes will all remain aligned.  In the photo you can see my scratch line with the punch marks, with the second and third photo showing the finished holes.  I also rounded the ends of the plates to make it look nicer.

Step 3: Bolting it together

Picture of Bolting it together
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The first photo shows how the the plates and pulleys are arranged without the other plate.  You can also see the short sections of copper pipe - I used those instead of having the carabiners resting on the threads of the bolts and does look nicer.  The second photo shows it put together - what you can't see is that I have a washer on the bolts running through the pulleys that are sandwiched between the pulley and the plate.  This is to keep so much of the pulley from rubbing on the plate, creating too much friction.  I used an old trick or the "cheap man's locknut" as I call them - the third photo shows two nuts, the one on the right has been hit one time (forcefully but not too much) to deform it.  This will make it grip the threads of the bolt pretty well, just like a lock nut.  Or you could use a split washer too, in any case you need something to keep it on the bolt - it spins enough with the pulley that it won't take long to unthread itself.  Last shot is another look at the B&T.  It works really well and I am pretty happy with it. 
caarntedd3 years ago
Great instructable! How about six Pulleys?
I am what holds this jig together *note username* therefore you must give credit to me B-) This is fairly straightforward though, and it is completely 'moddable'. 5/5 for simplistic design and straightforward construction (as well handling the "I only have these to work with" situation).
oompa (author)  nutsandbolts_644 years ago
Credit awarded!
Don't spend it at in one place =)
Thank you!
KellyCraig4 years ago
If the wood pulleys were going to be exposed to weather, one could use a hardening oil (e.g, tung oil, linseed oil, walnut cooking oil) or poly finish on them to extend their lives. Thinning 50% with mineral spirits, the oil or poly would soak in deep, where it would remain as the oil or poly dried.

If you stayed with the project, you could keep adding finish every fifteen minutes and as long as the wood soaked up the finish. When it wouldn't take anymore, wipe off the excess, to avoid orange peeling (it will, if you allow it to set more than fifteen or twenty minutes). After the first application(s) dries, go to a 25% mix, which will go much, much quicker. Then do a final with about 10% for oil or straight for poly.
oompa (author)  KellyCraig4 years ago
Like I mentioned, you could really make a nice looking set - I have yet to paint mine and probably won't. This set will be under the overhang of a roof and used by 3 kids ages 7, 9, & 9 and I figured that they won't last that long anyway so why make them pretty? I might redo them nicer and heavier duty if they fail.
KellyCraig4 years ago
For those with a band saw, circle cutting jigs are remarkable for putting out circles limited only by what you set your jig up do do. Mine will make circles from 2-1/2" to 36". One six inch circle, for example, only takes around thirty seconds, or less.

Really excellent instructable, by the way. I can see all sorts of possibilities. Thanks much.
oompa (author)  KellyCraig4 years ago
Thank you!
KellyCraig4 years ago
A while back, I dropped a newly acquired Sears Router Crafter, which uses pulleys to move a router along rods. That cost me one of the pulleys. I was bummed and panicked, but had a lot of light plexi around and nothing to lose trying to make my own pulley wheel. Using the hole saw approach, I cut three pieces. The center was, of course, smaller than the two outer layers. Once glued together, I was back in business.

It seems one could use the same approach, using plexi, aluminum or thinner plywood wood for these pulley wheels. I was just wondering if there would be any advantage to doing so (e.g, keeping the ropes in position, etc.)?
oompa (author)  KellyCraig4 years ago
I thought of that too - using three discs sandwiched together with the middle section smaller than the outside discs. I would have had to wait for the glue to dry and my patience wasn't long enough that day. I tried the lathe work with my drill though and that whole process was so easy and fast I stuck with it. The sandwiched discs would certainly give you more depth for the rope so it would be less likely to ride up and out the outside of the pulley, but I haven't had that problem yet. BTW plexiglass is useful stuff, isn't it?
velcro24 years ago
Very nice B&T. I would like to add that I didn't see what thickness the plywood was. I probably missed it. I would think 1-1/4" inch Ply. Why didn't you consider solid wood? Wet damp weather will cause the ply to de-laminate over time. I would also suggest a copper sleeve or Teflon (bushing) on the bolts holding the pulleys. Good idea to blunt the corners (radius the corners) of the Aluminium brackets whilst you are de-burring the edges so as to make it "user friendly". Not sure why you didn't opt for fiber lock hex nuts. Also, did you consider using solid pins with washers and cotter pins for the pulley axles? All in all, a very nice, creative and inexpensive Instructable. Thanks.
oompa (author)  velcro24 years ago
Plywood is 14 mm - I live in Italy so they do things a little different here. Solid wood is probably better, I just used what I had on hand. I didn't show it finished i.e. painted so that will offer some weather protection. The sleeve is a great idea and I thought of that, but I didn't have anything on hand. Lock nuts are pretty cheap but 10 seconds to hammer a nut (I'll leave the double entrende alone) or 10 minutes to walk to the store that isn't open due to siesta at that moment - you can see where my decision went. A lock nut would be easier and a solid pin with cotters would work great, I went with what I had on hand.
DavidM454 years ago
Looks great, great job it figures out to be pretty darn strong. I might double up the hardware store alum. carabiners ... for sure the kids will be hoisting each other up before you know it. LOL at least mine would have.
oompa (author)  DavidM454 years ago
Ha - funny you mention that as I was planning on keeping the bucket small enough to prevent them from doing that. I am sure that one way or another they will figure something out!
EmmettO4 years ago
Oh, cool! I've had trouble with side by side pulley set ups twisting badly. This might work better.

I've also been thinking of making a light duty crane, I might have to figure out a more complex system to be able to lift what I want, but this gives some ideas. Thanks.