I suppose it was used as a counter, sort of like the counters on X and Y axis.
I forgot to take my cam today but I would say that it is most definitely wear, why so much I dont know but the teeth should be the full width all the way down. I have a pic taken a while back, its not very clear as I had to zoom in, but you can just make out what the teeth are like
I would probably go for the Alu, just because thats what Bridgeport used, but the steel would probably be easier to obtain a finish on.
Hood
