Hello group,
I want to play around with some gear hobbing. Nothing fancy, but would like to tinker with it.
I want to cut two spur gears that mesh together, one having 100 teeth @1.9894 dia. and the other having 20 teeth @ .3979 diameter. This will give me a ratio of 5:1 and a tooth pitch of .0625. When I draw this up in CAD, I notice that the teeth will bump into each other as they rotate through.
For the hob, I plan on turning it on a lathe with a custom ground threading tool to match the tooth form. The actual hobbing will probably be done on my mill as there is more room on that machine for fixturing the blanks etc.
I am pretty sure that the shape of the threading tool is not going to be the exact shape of the tooth form. I suspect that the hob is going to alter the tooth shape to "automatically" provide the tooth shape to provide the clearances so that the points of the teeth don't rub as they rotate together.
Does anyone have any experience with home shop hobbing that can provide some pointers?
I have plenty of machining experience, but and pretty stupid when it comes to gear machining (except for making the blanks).
TIA!
Chris