On 2017-01-21, Bob Engelhardt wrote:
On 1/21/2017 2:04 PM, David Billington wrote:
There are some programs or javascripts on the net which will generate
gear profiles such as http://woodgears.ca/gear_cutting/template.html and
others so maybe try a few and print off the result to compare with. ...

Thanks - I tried that. It took about 6 attempts to get it printed at
full size, but it did. The problem was resolution: these teeth are only
3mm deep and 5mm pitch, so trying to match profiles is really hard. It
did look like 20 degree PA, though.

Hmmm ... Given that the lathe was from Taiwan (or maybe mainland
China -- not sure at that date) are you *sure* that it is an involute
gear which matches an Imperial DP? Look for "Module" gears to see
what you can find which is close to it in the metric world. It does not
really look like the usual involute profile -- of either DP. I'm not
sure what the pressure angles are for Module gears -- or whether they
even offer two common angles.

If that is the case, I'm not sure where you would go to get gear
cutters of the right size.

Your two sample images are both labeled "16 DP", but I do not
see a pressure angle label on either. I would guess that the one on the
left is the 20 degree PA.

Good Luck,
DoN.

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