The 14.5° Pressure Angle Standard for Involute Gearing - 200 YEARS OLD

The 14.5° Pressure Angle is a standard parameter used in gear design, manufacture and use. FOR 2 GEARS IN MESH THEY MUST HAVE THE SAME PRESSURE ANGLE and PITCH! The 200 year old history tells an interesting story and how this parameter became a STANDARD... https://bit.ly/3onfQon

There are really only 4 choices for commonly used pressure angles and they are;
14.5° Willis 1841 and possibly as early as 1820-Original Standard
20° Preferred Standard by DIN July 1927, AGMA 1981
25° Stronger-Noisy
30° Stronger-Really Noisy
Sticking with these standards will avoid high cost custom tooling.
Chapters
0:00 Intro
0:09 Definitions
1:12 History
1:57 Math & Theory
2:41 Practical Industry
3:24 14.5° The Moment of Creation
3:50 Modern Standards
4:31 Outro
There are other pressure angles but they are far less common; 15° An early German Standard, 22.5° and others higher than 30°. The 14.5° pressure angle decision by Willis and Brown was done before computers and late in the Industrial Revolution. 14.5° was practical and somewhat informed. Industry wanted interchangeable parts and gears and this was the solution. Gears with the 14.5° pressure angle are not the preferred standard anymore, but there are design niches where it is still the best choice.

There are many greats and notables in industrial gear history and this list will still leave some out: The person that invented the Antikythera Mechanism, Aristotle, Albrecth Durer, Gerard Desargues, Philippe de la Hire, Robert Hooke, Whitworth, Scheele, Pfauter, Fellows, Grant, Dudley, Buckingham and more can be found here... https://bit.ly/2LmFdbt

From the viewer "Martin E" (We are thankful and appreciative of quality feedback)
The British Standards Institute precedes all the others mentioned - it was founded in 1901 as the Engineering Standards Committee. Gear Specifications: The earliest I can find is BS 436 Specification for machine cut gears, dating from 1932, which was updated in 1940 and withdrawn in 1967 when BS436 was split to become BS436-1 though to BS436-5 those being replaced in 1996 by BS ISO 6336. The last update of 6336 was in 2019.

#pressureangle
#involute
#hobbingprocess

REFERENCES
1750 Euler, L., De Optissima Figura Rotarum Dentibus Tribuenda. In: Novi Commentarii academiae scientiarum Petropolitanae, 1750, pp. 119-135.

1733 Camus, C.-É.-L., “Sur la figure des dents des rouës, et des ai les des pignons, pour rendre les horloges plus parfaites”

1767 Euler, L., Supplementum. De figura dentium rotarum. In: Novi Commentarii academiae scientiarum Petropolitanae 11, 1767, pp. 207-231.


Willis R.E., "Principles of Mechanism: Designed for the Use of Students in the Universities, and for Engineering Students Generally (Cambridge Library Collection - Technology)", Longmans, Green & Co., London, 1841

Pfauter Hermann, Pfauter-Hobbing, "The Engineer's Handbook of Hobbing and Pfauter Hobs", Julius Springer, Berlin W9, 1936 especially pgs 121-126

Radzevich, Principal accomplishments in the scientific theory of gearing, Power Transmission, 2019, https://doi.org/10.1051/matecconf/201...

ATTRIBUTION
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