Wednesday, September 21, 2011

We invented the "Sidewalk Surfer".

The Boys of  Claremont were the first to make working skateboards. This was in 1961, as I recall. One member of the group saw an article in Popular Mechanic's magazine showing a simple design for converting a metal roller skate into a "Sidewalk Surfer." Like I said the design was primitive and needed refinement. The first step was to separate the the metal skate into two parts. The back part of the skate was nailed or screwed onto a 24" section of a 2X4 piece of wood. The front part of the skate was likewise attached to the front of the board. This created your "Sidewalk Surfing" machine. The device required you start by placing one foot on  the board. Then use the other foot to start pushing on the sidewalk to build up speed. When sufficient speed was achieved, the other foot was brought onto the board. This is were the surfing part began. The trick was to balance yourself on a 2X4 piece of lumber without falling off. Crashing could result in bruised egos or broken bones. Once you got the hang of how it worked, then you were ready for more speed. The search for the long run began. Incline was what you were looking for. In Claremont that was no problem. Since the city was built up against the foothills of the Sierra Nevada mountains, finding a hill was easy.
We tried little hills. Enough to give you the speed but you still felt like you were in control. Straight run with a gentle sloping to a flat area was the ideal situation.
Were we satisfied with what we had mastered? No way!  We were the Boys of Claremont and challenge and danger was our motto.
There was a new housing development being built in the hills above Claremont. The elevation was about 200 to 800 feet above that of the city. The roads had been put in but no houses. It was the ultimate run. It had wide lanes and winding roads going to the bottom. What could possibly go wrong?
Well, since we were still in jr. high, we had not been exposed to the science of physics. We didn't understand friction or inertia. First of all,  we were a 150 to 170 lbs object standing on a 2X4X24" piece of wood supported by four narrow metal wheels with unlubricated ball bearings inside. I don't remember the formula to calculate the amount of weight/force exerted on each metal wheel but I'm sure it exceeded its design.
Anyway we started down from the top of the road. Everything seemed to be going okay for me until I felt my skateboard start to shake violently.  I bailed off the board and took giant running steps until I gained control and was able to stop. I went back and found my skateboard only discover that my rear wheel had disintegrated. No wheel, no ball bearings, just a nub of an axle. First lesson learned. Friction multiplied by the force per square inch created enough heat to melt metal skate wheel bearings. As I stood there scratching my head, I looked down the hill to see my buddies approaching the first curve in the road. Instead of turning, I saw all of them ejected off their boards and fly through the air and make unacrobatic landings in the dirt beside the road.
Since to do this was my idea, I felt a little responsible for what had just happened. I watched to see if anybody was seriously injured. Luckily, everyone got up and dusted themselves off. As I stood there watching, I saw John motioning me to come on down. When he raised his arm and I could see blood flowing down the underside of it. I held my skateboard high in the air and pointed to the broken rear wheel to indicate I could not continue, thank god!
That's when I learned about inertia. That a body in motion tends to stay in motion and to change the direction requires the ability to apply energy to change the direction of that motion. Unfortunately, those who bit the dirt, found out the hard way that rigid metal skate wheels don't turn.
This didn't stop our quest for the perfect run. That was to go down the San Antonio flood spillway. But that's another story.