How to make wheels
How to make wheels for ammunition cart/ballista: By Baron Jonathas Reinisch
The following instructions are PER WHEEL
1) Supplies you'll need:
- 2' x2' x 1/2" piece of plywood
- 6 ft 1"x4"
- Radial Bearings (the ones with a lip like a train wheel, (see Fig1) Bore 1/2" O.D. 1 3/8" (from True Value / Ace/ Tractor Supply)(Lowes/HD do not carry the right ones)
- 1 1/4" drywall screws
- Sheet metal (a flat piece of duct work works great and is cheap)
- 1" roofing nails
2) set your chop saw to cut a 30 degree angle and cut 6 trapezoid pieces with the long side being 10 3/4 inches (see Fig 2 )
3) set your chop saw to cut a 90 degree angle and cut 2 squares from the left over
4) Glue and screw 3 of the trapezoids onto the plywood to form a half circle. Align the center trapezoid along one edge of the plywood. I recommend 1.25" drywall screws, that are screwed in from the back of the plywood so they are not seen on the pretty side. (See Fig 3)
5) Hold the other 3 trapezoids togeather by hand and line them up against the first three. Once aligned, clamp 2 in place then glue and screw the third. Remove the clamps from one of the two, glue and screw it. Then glue and screw the last one.
6) Use a yard stick to find the center of the wheel. Don't try to measure, simply line the yard stick up across each of the points and make a short line near the center. Where the three lines cross is the center, Drive a finishing nail through it.
7) Drill a small hole at the 1" mark on your yard stick, and another at the 10" mark (9 inches between the holes). You now have a big compass, use it to draw a 9" radius circle around the finishing nail.
8) Remove the finishing nail and Cut out the circle.
9) Find the center of one of both of the squares. Glue and Screw one of the squares into the middle of the wheel on the same side as the trapezoids.
10) From the back, use a small drill bit and drill through the nail hole all the way through the square on the front. (see Fig 4)
11) Glue and screw the other square onto the back side of the wheel, if you turn the square 45 degrees you can still screw into the back side of the wheel without hitting the screw heads for the first square.
12) From the front, using the same small drill bit, drill through the hole in the front square all the way though the back square. You have now maintained the exact center of your circle on both sides of the wheel.
13) Use a 1 1/8 hole saw to drill out the center of the wheel. You will probably have to drill from both sides. (see Fig 5)
14) One of the Radial Bearing should drop into the hole from each side of the wheel with the lip just catching so that it does not go completely inside the wheel. (see Fig 6)
15) Paint the wheel
16) Cut strips of metal that are just wider then the edge of the wheel from any piece of sheet metal. Then use the roofing nails, nail the strips around the edge of the wheel. Use a hammer and pound the metal edges so they are rounded over the edge of the wood.
To mount the wheel use a 1/2" steel rod as your axle hard mounted (not turning) to your frame. Slide your wheel with bearings onto the axle, then drill a small hole just outside of the wheel/bearing to put a pin though. (see FIg 7)
Repeat for the wheel on the other side.
I've used the same design for heavier loads, like Red who weighs a couple hundred pounds. Only design changes, use 1x4 on both sides of the plywood to make a fatter tire (still used 1/2" ply), and used 2x4 for the center squares instead of 1x4.