Two weeks ago a boy and his sis' came to use my shop, advice, and help. They chose basic thin-car designs that were easy and quick to build. I cut the cars from the blocks but they did the scroll saw work and they used the drill press to create a weight cavity. We melted and poured lead and they nailed the weight right at 5.0.
They each did all the work on the axles, using grit from 600 to 2,000, and the mags polish with micromesh. In my opinion, the new wheels are pretty good so we just ran them over a hand lathe to make sure they were square and clean. We did find one bad wheel that needed to be replaced.
They did a great job applying graphite, and we made sure the cars rolled straight. The kids weren't up to spending any more time, so we didn't go through a full alignment.
And the cars were spectacular! The girl had the absolute fastest overall car out of 75 (she was in sibs class), and the boy took 2nd place overall in the scout class. He wants to align the car before Districts so I'm sure we can squeeze a bunch of speed out of it.
I popped into their race today and it was pretty cool seeing them beat the perennial winners.