I just stumbled across an "advert" that resembles what I see on eBay. Very nice gears, but no sizes, tooth counts, or pitch. A pretty picture but no useful information. It brought to mind an old timers trick. With a piece of light sheet metal, roof flashing works good, cut a notch three point one (3.1) inches long. Wrap the sheet metal around the gear, the number of exposed teeth is the DP for that gear. If it is a very(!) large gear, make the notch 6.2 inches, if a very small gear, 1.6 inches. Then adjust the tooth count to match the multiple of the gauge.
The difference between 14, 16, and 18 DP gears is hard to judge by eye. Such a gauge is handy for that. It doesn't figure in pressure angle, but for older gears, 14-1/2 degree is a good guess. Metric modulus gears are simple enough to measure, sometimes DP is a problem. A quick and dirty solution.
EDIT: Corrected the larger size notch.
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The difference between 14, 16, and 18 DP gears is hard to judge by eye. Such a gauge is handy for that. It doesn't figure in pressure angle, but for older gears, 14-1/2 degree is a good guess. Metric modulus gears are simple enough to measure, sometimes DP is a problem. A quick and dirty solution.
EDIT: Corrected the larger size notch.
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