Friday, June 8, 2007

The Gearbox - Polishing the Outer Cover

So with the motor pretty much finished, it is time to turn my attentions to the gearbox - a 1958 Norton AMC 4 speed. First job is to get the outer cover polished so that I can send it off to have the leaky O rings replaced by proper oil seals, as was standard on the much later Mk3 Commandos - this is a service that Fair Spares America Inc ( in San Jose, CA undertakes at a reasonable price.

Once this is done, I will take the gearbox to Steve at European Cycles ( to check out the mechanical condition and see what is needed to make a reliable box out of it.

So, without further ado, on with the polishing. You can see from the photos that the old cover isn't in the best condition, with some deep gouges and scratches. First job is to give it a good clean with degreaser.

Once it was all clean, I attacked it with a fine file over the worst areas, and then 60 grit wet and dry paper attached to a disc on the drill.
Once I was happy that all the scratches and gouges were smoothed out, it was time for the jar of elbow grease and many grades of wet and dry, right up to 1500 grit. After a fair amount of back and forth between grits (my patience isn't the best) it was time for the buffing wheel and polishing compound.
I was actually pretty chuffed at how well it came out. There are still the remains of a couple of the deeper gouges, but they give it the character that a 50 year old piece of aluminium should have!