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Building a 1:8 Scale Panther: Part 2

The Gear Box... ‘The Thing’

On hearing it run for the first time when I collected it I commented to the supplier that it was, even being new, very, very noisy. I was told this was usual, he had heard worse and it would loosen up. I ran the ‘thing’ for about 10 hours in cycles and the noise if anything increased. Thankfully I have another good friend, a university qualified engineer, and I took it to him. After a thorough examination his only comment was that it was “One of the worst engineered pieces he had ever seen in his life”. Maybe I had a bad one!

John, my friend agreed to ‘sort it out’. Some three weeks later he invited me to go to his house. His explanation as to the problem amazed me. He showed me gear teeth under a microscope and commented that he thought they had been cut with a chain saw! The major reason for the noise was that the teeth on the gears did not mesh properly. He then got into a deep conversation regarding ‘pitch dead centres’ of gears etc.

In simple terms to the layman it would appear that the teeth are too few for the diameter of some of the gears. His conclusion was that the gear diameter of particular gears had been dictated by the diameter of the bearing that the gear shaft would run on. The gear had to go through the bearing mounting holes to be assembled and that was that, like it or lump it. He also changed some further 4 gears and 8 bearings as although the tank was new, some gears were very, very poorly made and some bearings had seized or had been damaged to such an extent when fitted no longer functioned. So now some $300 US poorer I have a gearbox that is very, very efficient, quiet and uses less than half the amps as it did before modification and will last.