Simple Wheel Preparation

Most of these techniques will apply to even the most-restrictive "wheel rules." All of those which I've read allow at least smoothing the outside diameter of the wheels to remove mold flash and irregularities. The rest covers similar cleanup to the axle hole and should be allowable, but please check your wheel rules to be sure.

All of the steps below are things that you can do with your son. I wouldn't trust 8-to-10-year-olds with power tools unsupervised, but this is a good opportunity for a little cooperative work and training. Also note the safety goggles. Please protect your eyes and get him in the habit of wearing protective eyewear whenever using power tools!

Tools and materials you'll need:

  • Safety goggles for both you and your son
  • A variable-speed electric drill (A drill press is even better)
  • A bench vise or stand for the drill
  • A wheel-turning mandrel (available from the Scout Shop or from your local hobby shop)
  • A small block of hardwood, about 1/2" x 1" x 2"
  • 220-grit aluminum oxide (dry) sandpaper
  • 400-grit and 1500-grit wet/dry sandpaper
  • Powdered Pumice (from the hardware store)
  • Polishing compound (I prefer "Maas Polishing Creme" from
    Maas International
    P.O. Box 128
    La Grange, IL 60525-0128)
  • A couple of soft cotton rags
  • A dish or margarine tub to hold water
  • A 3/16" drill bit
  • Pipe cleaners (the big fuzzy "craft" kind, not the skinny ones you'd use on a real pipe)
  • A pair of pliers (needle nose are preferred)

Steps in preparing the outside diameter of the wheels:

  • Clamp the drill in the vise, attach the wheel to the mandrel with the supplied screw and chuck it in the drill.
  • Tear off a piece of the 220-grit sandpaper to fit around the wood block. Running the drill at low speed, carefully sand the tread area of the wheel just enough to take off the mold "flash" at the outside edge of the tread and smooth the tread area down to take out the "dimple" which is typically where the wheel was cut off the "sprue" or mold tree. Also sand the inside edge of the tread just enough to remove the mold flash which is usually there, as well. Use light pressure and keep the sandpaper moving to avoid building up heat and scuffing or melting the surface of the wheel!
  • Using first the 400-grit and then the 1500-grit wet/dry sandpaper, wet, further smooth the tread (both the main flat surface and the inside edge) to remove the scratches left by the relatively coarse 220-grit sandpaper. As you use finer and finer abrasives, you can speed the drill up, especially with the wet/dry sandpaper and the pumice, since the water will keep the wheel cooler. Don't forget the inside edge of the tread!
  • Tear off a small piece of the rag, wet it, and dip it in the pumice. Polish the wheel with the pumice to get it ready for final polishing.
  • Using another piece of the rag and the polishing compound, bring the tread area to a near mirror finish. Remember to polish the inside edge of the tread, as well, since it will rub against the guide rail on the track. This final polish can be done at a relatively high speed if you are careful not to press too hard.

Steps in preparing the axle holes of the wheels:

  • Holding the wheel in one hand, and the 3/16" drill bit (or countersink bit) in the other, carefully clean up the mold flash at both ends of the axle hole. You don't want more than 1/16" of countersink depth, just enough so there is no ragged flash to run against the axle and cause drag.
  • Take a 3" length of the pipe cleaner and bend it back on itself. Using the pliers, crimp the wire center of the pipe cleaner so it is tightly folded. Chuck the cut ends of the pipe cleaner in the electric drill so the folded end is sticking straight out.
  • Put some polishing compound on the pipe cleaner and press the wheel over the pipe cleaner with the electric drill turning slowly.
  • Polish the inside of the axle hole by running the pipe cleaner with the drill and moving the wheel back and forth so the polishing compound is spread over the pipe cleaner and buffs the inside of the hole. You are after an absolute mirror finish here, since the surface finish will determine how much drag there is between wheel and axle.

A few more things to do for the finishing touches:

  • Take a small piece of 400 grit wet/dry and lay it face up on your work surface. Add a few drops of water and hold a wheel with the inside hub facing down. Move the wheel in a circular orbit, rocking it around the axis of the axle hole until all of the flash and rough edges are gone from the hub.
  • Repeat this process with the 1500 grit to further smooth the hub. You should end up with a just barely noticeable "crown" to the hub (higher in the center, lower on the edges) which reduces the surface area in contact with the car body and further reduces friction.