De Bruin wrote:Do these old drives with a big straight cut gear like this have any kind of viability/duration for/in continuous operation?
This is a good question. I am going to guess if you ran those drives continuously you would wear out the worm gears on the axles ten times and still not wear out those large spur gears connecting the motor to the worm shaft. I say that for two reasons. First, worm gears having sliding contact, which is high friction compared to spur gears, which have rolling contact. Additionally, the tooth stress in a gear is more-or-less inversely proportional to the gear diameter (all else being equal). That is, the small-diameter worm gears on the axles will have much higher tooth-stress than the large diameter spur gears. There can be mitigating effects, such as out-of-round or wobbly gears, but overall I'm betting those big spurs gears would last a long time -- if you could stand the growl.
Nortonville Phil wrote:..that PA it looks like a cast shell to me.
Agreed. Bob is not enamored with it and with good reason, but the collectors out there will value it as a piece of history (so, no, don't melt it down). My history-minded self just wants to know where it came from.
Nortonville Phil wrote:I wonder if Exacta ever made a copper PA.
I don't know -- The immediate post-war era produced a flurry of models. Only a handful sold in enough quantity to be well known (Varney Ten-Wheeler, GMC NW-2, Atwater F3, etc). Most other models have only scant documentation, if that. Some are rare enough to be mythical, and it's anybody's guess on those.
Jim