These are my own version of Soap shoes, which can grind on rails, ledges, and anywhere else a skateboarder or Agressive inliner can. They use a pair of shoes, a sliding material (some sort of plastic is probably best),and some glue.

You can buy "real" ones for $50-$80 but that's expensive, I don't like how they look, and I think mine are as good or better than store-bought ones.

This is my first instructable, so bear with me.

Step 1: Materials

These are the materials you will need:

Shoes: I used my old New Balances, any shoe that has a relatively thick bottom layer (everything under your foot) would work

Slide material: I used a UHMPWE cutting board. It is perfect for this use, other dense, smooth plastics would work,(PVC, teflon, etc) I don't really know about metal.

Glue: I used "Welder" glue. It was really cheap, and it has held up well. Barges glue is probably perfect for this, but it is kind of expensive/hard to find. WARNING: Shoe Goo isn't good, although it sounds like it would be.

Tools: Hacksaw, bench grinder, vise, belt sander, sharpie, xacto knife. You can probably substitute for some of these.

Step 2: Design and Cut Your Plate

In this step you will design and shape the plate that will be doing the grinding. Place your shoe on the plate material, and trace around the bottom. Then, decide where you want the plate to be on the sole. I chose to put it about where my arch is, slightly farther back thasn the middle. This is your choice.

Then , use the hacksaw to cut out a square containing your plate. This step sucks. My advice is to put it as close to the corner as you can. Then use the saw to shape the plate, giving you a rough "blank" plate.
Now use the grinder to finalize the outline. I'd also round off the edges that are going to come into contact with the ground, cause they can get annoying.

Step 3: Shape the Plate Surface.

This step is pretty simple, but it is kind of time consuming. You have to carve a channel in the plate. The purpose of this is to fit on the rail, ledge, or whatever you are grinding on.
Its kind of hard to explain, so I made a picture that does it for me.
I used the grinder to carve out an arc, until the grinders umm... curve got too wide for the arc I had drawn. Then I used the belt sander, which took a little while. I also sanded the edge to make it easier to grind with your shoe at an angle.

Step 4: Cutting the Shoe

Now comes the fun part: cutting up a pair of shoes.
use the hacksaw and cut along the line at the front and back of the plate. cut so that is is deep enough to fit the whole plate, but not so deep that it cuts into the sole. Then, bend the front part back, allowing you (with a little difficulty) to cut along the lenght of the shoe to the cut you made where the back of the plate would be. smooth up all the cut parts, and try to make them as even as possible.
Since I am already using the shoes that I made, I used a different pair for this step.

Step 5: Testing and Gluing

To test the shoe, just duct tape tha plate into the cut out part of your shoe. Then jump on some edges, make sure the plate dosent bend or crack, and that it is in a good position on your foot. May be even try grinding a little, just don't be surprised if you fall on your butt the first few times. When you are done having fun, take off the tape, slather the hole in your shoe with the glue of your choice, push in the plate, clamp it, and let it dry and harden overnight at least. Read the label on your glue tube.

Step 6: The Last Step.

Once your shoes are done, its time to try them out. First, practice jumping onto a ledge or low bar, then work on sliding a little, and get your confidence up. Pretty soon you will be ready to take them around town and look for spots to grind. I have yet to be kicked out of any public place, but I have gotten in trouble in school for grinding on the stairs. They arent really anything but shoes, so I think youd be okay.

One warning: don't go to a skatepark until you are pretty good, or you'll just get in the way of the other kids and they'll get mad and kick you out. I've gotten some pretty weird looks when grinding with these, but most people think they are cool.

have fun, and don't break anything important. (like your spine)