Vitamin K asked me to share how I shave my razors.
Note:
I do also shave scout wheels when I build cars to show my students the difference wheel mass makes at the finish line. For those who have not read my previous posts, I am an 8th grade physics teacher who uses pinewood derby cars accompanied by a technical journal as my students' final exam for my class. The kids each build a car and I help them discover the force, inertia, friction types (and reduction), velocity, acceleration, average speed, etc.
Back to shaving wheels without a lathe.......
Materials needed:
[list type=decimal][*]Drill press set at low speed[*]Pro Wheel mandrel (I buy mine at Maximum-Velocity but most hobby shops have one)
[*]2 small washers to use with the mandrel between the shaft and screw so it does not reshape or scratch the bore of the wheel.[*]wood rasp like this one
[*]wire brush to clean the rasp[*]utility knife with a fresh blade[*]1000 grit sandpaper[*]plastic polish[*]leather or soft cloth to apply polish[/list type=decimal]
Process for Ranger wheels
Ranger wheels are solid chunks of plastic, instead of the hollowed out ones. They are heavy, the hole can be off-center, they are molded from the edges, and most of them have flaws in the plastic. Here is a before and after:
I place the wheels in the mandrel between the spacers and screw it tight. Then I use the rasp to remove the plastic on one side of the wheel by keeping the rasp level (I have been known to tape the small yellow tubes inside bubble levels to the rasp to make it as perfect as possible) and applying gentle pressure. The plastic comes off in thin strands. As the plastic builds up on the rasp, I brush it onto the floor with a metal brush and continue shaving. Once the side of the wheel I am working on is flattened to the depth I desire, I use the utility level with the wheel surface to shave the rough surface. Be careful here not to melt the wheel. Slow and steady for no more than 6 seconds at a time. I then wet sand it (while still spinning) to polish it up. Once it is smooth, I remove the wheel, flip it over and repeat the process. When the wheel looks good, I use the plastic polish to really make them shine. Sometimes I drill holes in the finished wheels to lighten them up even more (These wheels are a softer plastic than the scout wheels, so I cannot go to thin).
For the scout style wheels:
I use the same mounting process, but I use the utility knife to first slowly carve the running surface off of the wheels by bringing the razor edge, held perpendicular to the wheel surface, in contact with the wheel to cut off the bulk of the wheel surface to get rid of friction. The remaining part of the wheel tread should be about 1-2 mm thick. I then smooth out the inner side of the wheel (the side facing the car) to a high gloss shine using the sandpaper and polish. This keeps the part that can contact the rail slick. I then use the rasp to remove material from the outer edge (hub cap looking area) of the wheel. I finish the job by sanding the area smooth and polishing as before.
CAUTION........expect to destroy a few wheels in this process and expect this process to take time. It takes me about 15 minutes to make a really good wheel, but it used to take me about 30 minutes. It does get easier with practice.
Note:
I do also shave scout wheels when I build cars to show my students the difference wheel mass makes at the finish line. For those who have not read my previous posts, I am an 8th grade physics teacher who uses pinewood derby cars accompanied by a technical journal as my students' final exam for my class. The kids each build a car and I help them discover the force, inertia, friction types (and reduction), velocity, acceleration, average speed, etc.
Back to shaving wheels without a lathe.......
Materials needed:
[list type=decimal][*]Drill press set at low speed[*]Pro Wheel mandrel (I buy mine at Maximum-Velocity but most hobby shops have one)
Process for Ranger wheels
Ranger wheels are solid chunks of plastic, instead of the hollowed out ones. They are heavy, the hole can be off-center, they are molded from the edges, and most of them have flaws in the plastic. Here is a before and after:
I place the wheels in the mandrel between the spacers and screw it tight. Then I use the rasp to remove the plastic on one side of the wheel by keeping the rasp level (I have been known to tape the small yellow tubes inside bubble levels to the rasp to make it as perfect as possible) and applying gentle pressure. The plastic comes off in thin strands. As the plastic builds up on the rasp, I brush it onto the floor with a metal brush and continue shaving. Once the side of the wheel I am working on is flattened to the depth I desire, I use the utility level with the wheel surface to shave the rough surface. Be careful here not to melt the wheel. Slow and steady for no more than 6 seconds at a time. I then wet sand it (while still spinning) to polish it up. Once it is smooth, I remove the wheel, flip it over and repeat the process. When the wheel looks good, I use the plastic polish to really make them shine. Sometimes I drill holes in the finished wheels to lighten them up even more (These wheels are a softer plastic than the scout wheels, so I cannot go to thin).
For the scout style wheels:
I use the same mounting process, but I use the utility knife to first slowly carve the running surface off of the wheels by bringing the razor edge, held perpendicular to the wheel surface, in contact with the wheel to cut off the bulk of the wheel surface to get rid of friction. The remaining part of the wheel tread should be about 1-2 mm thick. I then smooth out the inner side of the wheel (the side facing the car) to a high gloss shine using the sandpaper and polish. This keeps the part that can contact the rail slick. I then use the rasp to remove material from the outer edge (hub cap looking area) of the wheel. I finish the job by sanding the area smooth and polishing as before.
CAUTION........expect to destroy a few wheels in this process and expect this process to take time. It takes me about 15 minutes to make a really good wheel, but it used to take me about 30 minutes. It does get easier with practice.
