Continuing with that January 1912 issue of Industrial Engineering magazine … Imagine the courage it took to present a seven-page article on your gear system — complete with rating methods and design rules. Percy C. Day was several years away from joining The Falk Corporation in 1912, but he leveraged his explanation of gear tooth action and his staggered tooth “herringbone” gears of the “Wuest type” (When oppositely angled teeth meet in the middle of a herringbone gear, the alignment may be staggered so that tooth tip meets tooth trough; it is the unique defining characteristic of a Wuest-type herringbone gear, named after its inventor.) into that move across the Atlantic Ocean. The article reads surprisingly well 115 years later; if we re-published it in the current magazine very few changes would be needed. It represents an early recognition of the importance of limiting cutting errors, explains rolling and sliding tooth action very nicely, and presents a design philosophy that would not be out of place in a modern gear shop. The “standard” tooth proportions used in this paper are still in common use as AGMA 20 degree stub. The 23 degree helix angle is still popular and many designers continue to follow the face width guidance offered. How many machine components can trace their design origins that far back? Do any of you have old references you still use? (Editor's Note: For the full article referenced in this post, click here: Herringbone Gears - Percy Day)Continuing with that January 1912 issue of Industrial Engineering magazine … Imagine the courage it took to present a seven-page article on your gear system — complete with rating methods and design rules. Percy C. Day was several years away from joining The Falk Corporation in 1912, but he leveraged his explanation of gear tooth action and his staggered tooth “herringbone” gears of the “Wuest type” (When oppositely angled teeth meet in the middle of a herringbone gear, the alignment may be staggered so that tooth tip meets tooth trough; it is the unique defining characteristic of a Wuest-type herringbone gear, named after its inventor.) into that move across the Atlantic Ocean. The article reads surprisingly well 115 years later; if we re-published it in the current magazine very few changes would be needed. It represents an early recognition of the importance of limiting cutting errors, explains rolling and sliding tooth action very nicely, and presents a design philosophy that would not be out of place in a modern gear shop. The “standard” tooth proportions used in this paper are still in common use as AGMA 20 degree stub. The 23 degree helix angle is still popular and many designers continue to follow the face width guidance offered. How many machine components can trace their design origins that far back? Do any of you have old references you still use? (Editor's Note: For the full article referenced in this post, click here: Herringbone Gears - Percy Day)