This is a copy of the Inside Ride Emachine Free Motion Floating rollers. It works fantastically.

Step 1: Supplies

-1-8ft section of 1.5" Diameter PVC pipe
-3-2x4's
-4-6 Rollerblade wheels, preferably equal sizes. Skateboard wheels could work also.
-2-3 2' 6" Metal rods the diameter of the inside of your Rollerblade wheels, mine were 1/4".
-4-6 Metal end caps the size of your metal rod. They look like little hats. One is shown in the picture.
-2-36" Black Rubber Tie-Down Straps.
-2 bolts with nuts. About 2.5-3".
-4 pretty large washers.
-Some screws and some nails.
-A hacksaw
-If your rollerblades came with small spacers, keep them, but if not it''s really not important.
-A countersink bit isn't absolutely necessary, but allows the screw head to lay flush.
-Wood glue if you'd like.
-Preferably small table saw, but jig saw could work with a steady hand.
-A basic set of tools would come in handy. A wrench, hammer, and screwdriver were useful.
-And obviously, your rollers.
-The first nine supplies(except the rollerblade wheels) cost me only $35 at The Home Depot.

Step 2: Split the PVC Pipe

First measure the length of your rollers. Then add 24"to that because that gives 12 inches of rolling space on each side, this is how long you will cut your PVC, if it adds to more than 8ft(I don't know of any rollers this long) it is OK, as long as you have at least 8 inches on each side. Make the cut there so you have your length of PVC. Now run this through the table saw long ways so it splits in half, you may have to flip it over and cut twice if your blade is not high enough, I did. Just make sure you don't twist the pipe too much while running through the saw. If you don't have a table saw and only a jig saw, just do your best and tell me how it worked.

Step 3: Cut the Wood and Screw the PVC In.

First line the wood up with your rollers so they are even and mark in 3 spots where you want to put the wheels on each piece of wood, add 6 inches to each side of those and mark that off. Don't screw within those marks because that is where the wheels are going to roll. Place the PVC on the wood in the center with the wood laying flat. Countersink if you can then screw in. I put in 6 screws on each piece of wood and it is extremely sturdy.

Step 4: Drill Holes for the Axle

This is pretty simple. Whatever the size of your metal rod is, that is the size drill bit you will use. My rollers had 6 legs that I drilled into, you may have to improvise if yours are different. I know of some with only 4 legs, I would say that wherever the rollers contact the ground, put an axle. Just drill holes for the rod in two or three spots on both sides, making sure the holes opposite each other are in the exact same position, so the axle is not crooked. Now make sure the belt that spins the rollers is in the position it needs to be to function. I made the stupid mistake of not doing this and I had to take apart the assembly after it was complete. Then slide the axle through, you should have to bang it through with a mallet, don't use a metal hammer unless that's all you have, it will make it difficult for the metal cap placement. Also, the axle is not supposed to spin.

Step 5: Attaching the Wheels

First, measure 2 1/2 Inches from the side of the rollers to the end of the metal rod, cut there with a hacksaw. Repeat on each axle until they are all done. Then put the spacers on if they came, if not then it is not a big deal. Then put the wheel on, then pound the metal end cap on with a hammer making sure you brace the other end so you don't just push the axle through. Do this do every one then put the PVC-wood combo under each side and depending on the size of your wheels the axle may touch your PVC, mine did. I ran the PVC-wood combo through the table saw with the guide on and almost ruined the PVC by cutting it too shallow. SO DO NOT USE THE GUIDE WHEN MAKING THE PVC MORE SHALLOW. Do it by hand and only shave off a small amount. If you made a perfect first split then you shouldn't have to worry about it.

Step 6: Making the Frame

First make sure your rollers roll in the PVC channel smoothly, and the two pieces of wood are parallel. Measure the distance from the outside of the two boards. This will be the length of the cross boards. Cut two of them and put them in place as shown in the picture below, vertically. Do this on each side. A brace in the middle is not necessary, i didn't use one and mine is sturdy, but you can place one if you want. Nail or screw these in and use glue if you want, I did, wood glue is very strong.

Step 7: Putting on the Rubber Straps

Put the rollers in their place on the frame and center them. Use larger screws and the large washers to tie down the strap to the wood as shown in the third picture. Then you will need a the bolt to tie the strap the the frame. Stretch the strap out until there is no slack but not so tight to where there is a lot of tension. Drill a hole through the strap and the rollers the size of the bolt. Make sure you put it in a spot where it does not impede the function of the rollers. Do the same thing on the other side. Now your rollers are complete!

Step 8: Optional Bumpers

Simply cut a piece of angle iron(4th picture), available at the home depot, cut as shown in photo 2-3. Do this twice. Now you have two pieces of angle iron about as wide as shown in picture five. Take the original axle from your rollerblades and put it through the short end of the angle iron. Pack it with washers to make it really tight, but make sure the wheel still spins. To ensure this you can use the spacers that came with the rollerblades right next to each side of the wheel and then put washers on. Put this on the outside of the rollers axle and replace the nut and you are good to go!