What does this ring gear fit?

[1911 T Guy]

Does anyone know what this ring gear and pinion fit? Post here or email me at address in pictures. Thanks Dan 

 

[dustycrusty]

40 /  11 =3.63:1.   Model T Ford.

 

https://www.macsautoparts.com/model-t-ford-ring-pinion-gear-set-standard-3-63-1-ratio-40-tooth-ring-gear-11-tooth-pinion-gear-16-54007-1.html?utm_source=google&utm_medium=cpc&adpos=&scid=scplp16-54007-1&sc_intid=16-54007-1&gclsrc=aw.ds&&gclid=Cj0KCQiA1pyCBhCtARIsAHaY_5eSzEruIMczzJVqqeq9So_H7IMAB-LC8VpHAOV2K0T01vpvjifzeXcaAlv2EALw_wcB

[41 Su8]

These are hypoid gears, Model T had straight cut gears.

[Gary_Ash]

The gear set is 42 tooth ring gear and 11 tooth pinion, as stamped on the parts, for a 3.82:1 ratio.  Neither the 1349 ring nor the 2349 pinion numbers show up in my Hollander 1920s-1948 book.  I'm guessing that the 12 and 36 numbers indicate they were made in December, 1936.  Hollander doesn't show many R&P sets at 42-11, but mid-late 1930's GM products used them.  The GM part numbers were different, so maybe these were made by an independent company, especially as the numbers look hand-stamped.

[1911 T Guy]

I found a picture online for a 28 Chevy that looks a lot like this set. Could not see the back of pinion, to see if the shoulder was there. 
Anyone have a picture of 1928 Chevy ring gear? Thanks Dan 

[dustycrusty]

1 hour ago, 41 Su8 said:

These are hypoid gears, Model T had straight cut gears.

Thats it, I'm getting glasses!

[Layden B]

The pair are standard ratio for 1926-1928 Chevrolet K, V, X, AA, AB

Yes Chevrolet has a shoulder on the back of the pinion.

[Layden B]

Just for you Model T Guys, Republic Gear did make an aftermarket spiral set for Model T Fords, here is a set.

[1911 T Guy]

Ok looks like they are 26-29 Chevy. Thanks for the info. Dan 

[C Carl]

8 hours ago, 41 Su8 said:

These are hypoid gears, Model T had straight cut gears.

NOT hypoid. These are simply spiral bevel gears. Spiral bevel gears in which the input and output shafts lie in the same plane are technically called spiral bevel gears. Spiral bevel gears in which there is an offset, in other words, the input and output shafts lie in different planes, are technically called skew spiral bevel gears. In order to run extreme offset, clever engineers at Gleason developed hypoid in the early 1920s. In order to achieve this, they invented a hybrid between skew spiral bevel, and worm gearing. So that being the case, there is a sliding component to the contact face. And that is why hypoid, as must worm gearing, must use EP lubricants. I learned this from Marks’ Mechanical Engineers Handbook, 3rd edition, 1930. I have 1924, and 1927  Cadillacs, and I recommend Marks’ of just a few years more recent than your old car. Certainly an engineer will derive more from Marks’ than a mere civilian such as myself, but even if you, like I am , are not an engineer, you will get a lot out of these books. The state of the engineering art 80-90-100 years ago is very impressive and informative to anyone who looks into it.      -     Carl. 

[Layden B]

Not 1929 Chevrolet. The new AC 6 cylinder had a new rear axle too.

[C Carl]

Pre-, and immediately post-war editions of Marks’ , editions first through sixth, are 1916, 1924, 1930, 1941, 1951, and 1958, for anyone interested. I got my 1930 from the late, great Cliff’s Books which was on Colorado Blvd. in Pasadena, CA. Next was my 1958 from University of Washington surplus for two bits, yes, twenty-five cents (!). I needed to get my 1924 quickly, so my friend Alex Voss who was an automotive engineer in Detroit in a former life, found it for me. Alex is Books4Cars.com, or 206-721-3077 in Seattle.    -    Carl 

[C Carl]

And here, to give an example of Marks’ relative to the topic at hand , from 3rd. Ed. 1930 :

 

These pages are indicative of the relatively more easily understood explanations. High school algebra and trigonometry are sufficient for a mechanically sophisticated mind. For those of you who know higher mathematics, rest assured that plenty of topics are fully covered, and your calculus skills and engineering degree will serve you well. Other simpler topics are illustrated with easily comprehensible graphs, and I find those the most satisfying. I have to work very hard to wrap some of my head around portions of some other pages . At that, I only receive a partial understanding, but some understanding can be quite valuable , and some degree of understanding is far better than none at all.   -    Carl 

 

 

[Gary_Ash]

Based on Carl’s recommendation, I bought a 1941 edition of Marks’ Handbook on Amazon.  Admittedly, I am an engineer and physicist, but the book covers everything from steam engines to surveying to airplane propellors to industrial management, 2274 pages on useful info. If a young person studied the book in detail, it would be equivalent to a very good engineering education today, even using the 1941 book. The section on automobile engines explains how the dimensions for cylinder wall thickness, piston rod dimensions, and many other things were selected. Even the 1941 edition covers turbocharging and fuel injection.  It’s good entertainment for little money.