yes! another excuse to bust out my favorite stationary – green engineering graph paper. the plan was to build a 12-foot-long teeter-totter with an approach angle of 20-22°. the materials needed are as follows…
for the plank (rideable area):
- 2 – 2x6x12″
- 6 – 1x4x11″
for the base:
- 2 – 4x4x2
- 6 – 2x4x7-1/4″
- 4 – 2x4x32″ (30° cuts on both ends)
- 2 – 2x4x30″
- 2 – 2x4x55.5″ (optional supports)
for the pivot box:
- 2 – 2x6x11″
- 2 – 2x6x11″ (can be slightly shorter in length)
and to hold it all together:
- 1 – 3/4″ steel rod (min length of 14″)
now you’re probably wondering what to do with all this wood. let’s start by building the base. lay the two 4x4x2 pieces side-by-side and nail on a 2x4x7-1/4″ horizontally against the 4x4s at opposite ends (looking at a side view). do this on both sides of the 4x4s.
you will want to place the last 2×4 pieces on the 4x4s at a point where when the side legs (2x4x32″) are attached to the 4×4, the legs can also be nailed to the side of the 2×4. find this point (it is roughly at 12″ from the top of the 4×4 to the center of the 2×4) and nail the 2x4s onto both sides of the 4x4s.
now looking at the connected 4x4s on the side without the 2x4s, position the 2x4x32″ pieces so that their 30° cuts meet and form a straight vertical line at the center of the 4×4. find the height on the 4×4 (approx. 10″ from the top of the 4×4 to the center of the 2×4 leg) that allows the far ends of the legs are level on the ground. check this on a flat surface (not the ground where you will finally place the base) and nail the legs on. repeat on the other side.
to build the pivot box, attach the 2×6 pieces so that the 11″ pieces are opposite each other and 10″ pieces are opposite each other.
put the pivot box over the base with the 10″ side being on the side with the legs. center (side to side) the box, then drill a hole (it should be slightly bigger than the diameter of your rod) through the box and the 4x4s above the legs where you will be putting the rod through.
now you can put the rod through the box and 4x4s. or you can consider putting pvc pipe through the hole first and then putting the steel rod though, this should prevent the rod from wearing into the wood (make modifications as necessary – drill a bigger hole, etc.). secure the rod on each end with washers and bolts.
with the base and pivot done, you can make the riding surface. simply lay the 2x6x12 pieces together and attach them by nailing the 1x4x11″ pieces along what will be the underside of the riding surface. leave about a 2′ gap in the center and space the three 1x4s evenly on both ends.
the last step is to nail this riding surface to the pivot box. if you just position the riding surface off center of the base & pivot box, the teeter totter will be weighted on the longer side which you can use as the approach side.