Thanks for all your help guys.
I realized that the part business for older machines is a total rip-off.
I expected this from companies but not form like minded machinists.
I always was under the impression, that a forum links like minded people together and that there is some kind of camaraderie.
But hey, that's obviously the world we are living in now . . .
And I have to admit that most of the tips and links I got here have been very helpful and got got the ball rolling.
Here is what we did to solve the problem with the worn out brass gear.
We removed the carriage gear box, took the brass gear out (almost no teeth anymore), counted the teeth to make sure the manual was right and did some calculation.
We also measured the worm gear carefully and and determined the depth and angle of the teeth to cut.
We still had some brass in stock which served as the raw material. The rest was just a lot of work but no rocket science and took us the whole morning.
The 6 keyways to fit the new gear to the shaft produced some head scratching, but we ground a proper tool and with the help of our rotary table and our milling head this was done in another hour or so.
It was a snug fit and with a few blows with a rubber mallet the gear was in place.
Assembling the gear box, sealing the bottom plate, which serves as a oil pan, lifting the gear box in place, doing the final assembly, filling up oil and looking proudly at our work was done in another 3 hours.
The final moment arrived. Power up!!!
Yippie, all runs smooth and perfect.
Took us 1 day, 1.5 guys and saved us about 1000 bucks for a new gear and about 500 bucks for a used one.
Thanks again to all, who tried to help!!!
Cheers
Latheskip