On eBay at the moment are 2 sets of circular pitch gear cutters described as No 5 and No 7.
The pitch on the No 5 is given as .6283 on 2 of the cutters and .4488 on the No 7 gears.
I imagine that the No refers to which number in a standard set of 8 cutters but the Circular Pitches given don't seem to match with any of the tables.
Can someone enlighten me?
Brian