If A Gear Cutter Is Not Marked...

[CarlosA]

Do I just assume it is 14 1/2 degree pressure angle? I have some really old Browne & sharpe gear cutters that don't say. I want to track down some of the holes in my collection.

 

[dlane]

Houdy, , use them see what happens

 

[rgray]

Old and B&S. I would think it a pretty safe bet they are 14 1/2 deg.
I have seen suggestions for finding a gears angle by borrowing the grand kids playdough and rolling the gear through it. Then cut away the side so a visible "rack" is showing. You can then measure the angle with a protractor.
Should work the same rolling the cutter through the dough.

 

[ruralearl]

Hi Carlos, If the depth (D+f) is marked as this one is use the formula 2.157/DP = (D+f) for 14.5 degree PA; for 20 degree PA it is 1.800/DP = (D+f) . So the one in your photo is 14.5 PA as 2.157/48 = .0449. In my experience most old unmarked cutters are 14.5 as rgray said. Regards, Earl

 

[CarlosA]

Hi Carlos, If the depth (D+f) is marked as this one is use the formula 2.157/DP = (D+f) for 14.5 degree PA; for 20 degree PA it is 1.800/DP = (D+f) . So the one in your photo is 14.5 PA as 2.157/48 = .0449. In my experience most old unmarked cutters are 14.5 as rgray said. Regards, Earl

Thanks... I knew there must be some formula. Any chance such a formula exists for module cutters? Maybe it's the same?

 

[ruralearl]

Hi Carlos, I don't know, maybe something in Machinerys Handbook. There must be some metric experts here, too. Regards, e