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Notes on building a ferris wheel from the Master Builder himself, Marshall Ellis:
1. Wood: Hickory and oak work best. They're straight, have even diameters, and they're strong. You can get away with poplar for the tripods. I prefer hickory for the seat handles - super strong.
2. Tools: You'll want a sharp pocket knife, a good crosscut saw, a sharp axe, and a chainsaw. DON'T forget gloves for tightening the lashings, or else you'll get eaten alive.
3. You can get away with pretty small diameter stuff. For the tripods, 5-6" diameter minimum ought to do it. The butt ends shouldn't be real beefy I'd say no more than 8" - any more than that and lifting them will be a real problem.Since you'll be bracing them, they should stay plenty stiff.
For the long pieces that hold the seats and axle, oak or hickory, about 12-13 feet long each will do. Diameter doesn't need to exceed 4-5". Make sure they're staight and as evenly sized from one end to the other as possible. I'll usually cut the tree and then cut a section from that. It's real important that you get really straight trees, so take your time and look carefully. For the axle, 5-6" diameter and about 10 feet long ought to do it. Remember, you'll want to notch the axle where it crosses the long seat pieces, so don't go too skinny here. The axle blocks can also be about 4-6" diameter, and probably 5 feet long (you'll probably end up trimming them). I usually manage to get the axle blocks and the axle from one tree. Be sure to cut all of these long, that way you can trim to length.
For small pieces, like the seat handles and the "X" across the axle, cut down saplings and take the whole tree. (That way you can trim them to length). Look for stuff 1.5" or so in diameter.
4. Wood Needs:
5. Order of Construction:
1. Lay out the tripods and lash them about 4 feet from the tops. Place the longer pole in the middle. This needs to be a semi-loose shear lashing. 10 wraps or so ought to do it. Stand them up and position them so that they're right across from each other, about 6-8 feet apart. Go ahead and brace them on two sides - leave the inside opening unbraced. Stake down the long pole that extends away from the action.
2. Lay the long poles that hold the seats/axle out parallel to each other and sit between them to get the width right for the seats. Measure that with a piece of rope, and keep that piece of rope for sizing the other end. Cut a shallow, flat notch (.5" or so) in each pole to cradle the seat handle. Use the saw to cut parallel sections and then smooth it with a good knife. Lash one handle completely, then go to the other end, notch it, size it for the right width, and lash. For the width, think about what you'll need to do to get your elbows through. Maybe 3 feet wide?
When you lash the handles, I usually put them in about 8 inches or so from the end of the long poles. Mark the center of each long pole so you'll know where to center the axle. Square lashes for all of the seat handle lashes - 3 wraps and 2 fraps. Make sure they're super tight and neat. Soak them with water once finished.
3. Center the axle across the long seat poles, center it, mark where it will connect with the long poles, and then cut two shallow, flat notches on the axle where it crosses the long seat poles (Be sure that you notch the axle. Do NOT notch the long poles for this). Same as before: use the saw and flatten them with a good knife or axe. They should be about three-quarters of an inch deep. Make sure that you notch them so that they fit as tightly as possible to the diameter of the seat poles. Lash eash side with square lashings - probably 4 wraps and 3 fraps, but maybe 5 and 4. Look and see what works best. Make sure they're super tight and neat. Soak when done.
4. Line up one side of "X" lashing with a small diameter pole. Lash it down with diagonal lashes. On the second piece of the "X", this piece will be under a lot of pressure, so use a piece that's a little less thick for this. It will be key to make sure that you have someone anchoring the loose end while you tie the first end. Be careful here! It can be spring loaded, so as you bend it down, do it in stages and keep the pressure even. DON'T let go once you have it down or you could get whacked. Then do the mother lash where the "X" crosses. This one needs to be super tight. Diagonal lashes for all of these. Soak when done.
5. Move the wheel into the tripods (if it's not already there) and position it so that the ends of the axle are directly beneath the tops of the tripods. Sling the top of each tripod (a sling and biner work fine), tie off on each end of the axle, pass up through the biner, and hoist it up as high as you can get it and tie it off. Don't worry about getting it level - that doesn't matter at this point. Also, once you've got it tied off, make sure that you have each tripod braced off on each side. This will give you something to stand on and will also stiffen up the tripods.
6. Hoist up an axle block on one side and lash it in place. Remember to notch the blocks before hoisting. Make the notches about 1.5 inches deep, and make them flat and smooth. The blocks should go about 10 feet off the ground, but you'll have to eyeball it based on high long the seat poles are. If you lash them too high, it'll be hard for the kids to get up in the seats. Too low, and their feet will drag.
Once you have the first block in place, measure the height and repeat on the other side. These will be awkward to lash, but the lashes don't need to be super tight. The weight of the block against the rope will be enough. Just make sure the fraps are tight and you'll be fine. Probably 5 or 6 wraps and 4 or 5 fraps on these. Don't worry about soaking these.
Make sure of two things: 1. Get the height as even as possible. 2. Make sure that the axle block notches are right in line with each other so that the axle rides across them as a perpendicular angle.
7. Once you get the blocks lashed, untie the ropes and lower the wheel into them. If you've gotten the axle block heights even, then you should be fine. Attach your seats, pick your test pilots, and see how it rides.
Notes provided by Marshall Ellis
Safety notes: