Ok, I think I am on the verge of understanding some of this. Please let me know if I am dead on, close, or not even in the same state.
So im reading more on differences between backlash and tooth thickness, and I think I had one of them headaches with pictures.....you know, an thought.
So for example, using the same part specs I started this thread with.
I have this part, specs are:
Pitch Diam = 1.120 ( .03 smaller from standard)
Number Of Teeth = 23
DP = 20
PA = 20
MOW = 1.23405 ( .0864 wires )
So here is my thinking, and please tell me if I am starting to grasp this.
1: They call out a pitch diameter smaller than standard which tells me the gear has been reduced.
2: I should not assume, but for the sake of this I will. Ill assume half the pitch diam of 1.120 is the Gears portion of the Gear / Pinion Operating Center Distance
3: chugging out calculations, to thin the teeth enough to obtain a working pitch diam of 1.120, the teeth need to be thinned by .01092".
4: So this reduction in gear tooth is probably the same increase in pinion to allow the pinion to mesh at this 1.120 pitch diameter with the gear( tight mesh )
5: More chugging calculations show that with a tooth thinned by .01092" with .0864 wires my MOW is 1.240388, not the 1.23405 they ask for.
6: Now leaving the tooth thinned at .01092 putting me at a 1.12 Pitch diam, I add a bit of backlash into the mix, dropping my MOW down to what the print calls for. .01092 Tooth reduction, with .002405 backlash, I get the proper MOW.
Can I say that this gear has been reduced to operate at 1.120 pitch diam, with .0024 backlash?