Ok,
here are a few Excel chart results of some initial PE measurement.
I have only done a rough PEC curve and tried it just once.
I'm pretty satisfied this gear is a winner. I hope I don't chew this one out
and can, at a later stage , make a similar one from brass or steel
and duplicate the machining sequence.
This gear has so far (gone about a 1/4 of the way around the gear)
got a PE (without PEC on) of about +/- 5 pixels.
This is slightly over +/- 5 arc seconds with a conversion of 1.14 arc sec per
pixel.
Worm gear mark one had +/- 25 pixel drift (see post 117)
Thanks to Andrew (Mithrandir) and Sheeny for the tips in Excel.
Steve