Berliner Fiber Gear Specification

[Django]

Does anyone know the correct pressure angle for a Berliner fiber gear? Cutting gears is a trade in itself and I have not cut gears since trade school, (many years ago). The fiber gear on my Canadian Berliner Type A is serviceable, but should probably be replaced at some time. I was also wondering if it is the same gear as those on early Victor Royals, (but with different mounting).

Thanks

[JerryVan]

Nearly every gear I've made for phonographs has been a 14-½ degree pressure angle. I'd be very surprised if the Berliner gear were any different. You probably already know that the O.D.=(N+2)/P.

It may be difficult to get a cutter for the pitch you need. Most cutters sold today only go up to 48P. Not sure what pitch you need. If you can't find one I may be able to help you.

[Django]

Nearly every gear I've made for phonographs has been a 14-½ degree pressure angle. I'd be very surprised if the Berliner gear were any different. You probably already know that the O.D.=(N+2)/P.

It may be difficult to get a cutter for the pitch you need. Most cutters sold today only go up to 48P. Not sure what pitch you need. If you can't find one I may be able to help you.

Thanks for the help. I have not cut gears in many years, so I will have to do some more reading since I want to get it right the first time. I figure that I will probably stack the blanks and do some extras while I am at it. I have an indexing attachment for my Moore rotary table, so I will just need the cutter, some calculations and time. I think that you are correct about the 14-½ pressure angle. I decided to go back to the first edition of the Machinery's Handbook to see what was the most common pressure angle in 1914, and the standard, and only angle described was 14-½, so it is likely.

[JerryVan]

The cutters usually have a "D+F" number etched on them. This would be your depth of cut after touching off on the O.D. However, if you like, I can tell you the what the measurement over wires would be if you give me the gear specs. It's more exact, but the D+F number is usually very close.

By the way, a Moore rotary is a darn fine thing! I guess you know that. I use a dividing head.