Portable Details

The track was constructed as a 10 foot circle. Then I added a 4 foot straight section to each side. Later I added another 4 foot straight for a 10 x 18 oval. Lastly I made two more curves and two more straights to make an 18x18 triangle. Seen here is the original design in 10x14 oval.

The top is made of 3/4" OSB and then painted with an oil based paint to protect it from the water. It has held up surprisingly well over the last 5 years. The top is 14" wide all the way around.

The legs are probably the most asked about design. It is modeled after some supports I made with rollers on top for supporting sheets of plywood in the workshop. The biggest disadvantage of these legs is their weight. However, they are very strong and stable. They also allow me to setup the portable by myself.

The upper half is a 2x4 with a 5/8" slot cut down the middle. The bottom half is another 2x4 with 1x4s screwed onto the sides to create a "U" channel for the upper board to slide in. The "U" channels is then screwed and glued to a small 2x4. That is screwed and glued to the cross leg and the cross leg has two 1x4 pads on the bottom. A 1/2 inch lag bolt goes through the lower 2x4 and slides in the slot. This design gives me about 14" of travel. What you don't see is that the upper half of the leg is held to the bottom of the top using a standard door hinge. So for transport the nut is spun off, the lower half of the leg is removed and then the nut is spun back on. The upper leg then folds up under the track and is held there with a bungee cord.

	The nut assembly is a hand made wooden nut holder basically. I cut the nuts on the table saw and chop saw and then sanded the edges, I then drilled a 1/2" hole in the center, placed the nut on top and traced out the part I needed to chisel out. I tried not to chisel it all out so that the nut would fit in their snug. Behind the nut assembly is a large fender washer and then a smaller fender washer. I didn't want the pressure of the nut to imbed the washer into the wood. So I needed a large washer for more surface area.
	One other detail is how the top is held together. In order to keep the top sections aligned I used the alignment hardware found on double hung closet doors. It keeps both of the tops at the same height. Then I purchased Draw Hasps to clamp the two sections together and keep them from separating. Overall it was a good design but after we started using it I found I needed more strength at the joints. I ended up making hold down clamps where I could slide a piece of angle iron in to keep the joint from flexing. The next time the track is up I will take some more pictures of the upgrades I have done. JRF