Spur gear computations

**thehomeengineer** · Feb 16, 2018, 02:12 PM

Hi Marv
I was very lucky to have a very dear friend (Miles) who was mad for gear cutting. What he didn't know about the subject was incredible. Unfortunately, he is no longer with us. What was even more impressive about the man he was self-taught as he was a retired Medical Doctor.
He made his own hobs and had built a hob backing off tool and a small hobbing machine along with tool and cutter machinery to support his passion for gear cutting.
My Foden steam wagon needed a 111 tooth gear which is difficult to do with a manual 40:1 dividing head. (not impossible but a compound gear train has to be used)
Miles offered me the access to one of his gear hobbing machines and this was used to cut all the gear blanks for the engine. I have included some photos of the machine below and the finished gears.