Gearbox Mesh Question

[sanddrag]

Perhaps the .005 was giving you too much spacing and the tooth face was not contacting the correct point in the tooth valley? What pitch and PA gears are you using. We use 20P 20*PA. Last year, we set them at the exact C-C distance and we had a couple tight spots. This year, we added .002 to that distance and it runs smooth as silk. We did however receive one gear from Martin that was 20P 1/2" face but 14.5*PA They don't even make those! It must have been a mishap in the manufacturing line. It ran but it was really super tight. We replaced it with another correctly made gear and again, smooth as silk.

I would look for other reasons your gearbox is tight other than the C-C distance. Is it tight in just one spot? Try to "time" the tightness to a specific gear. Also, get a really good magnifying glass and look at the interface between tooth and valley to make sure it all looks okay. This is how we found that our defect gear had a different PA.

EDIT: Last year with the exact spacing we dry ran it in to free it up. This year, there really was no run in required or performed.