I've seen it many times with reverence to improved crank shafts. But here it is on a pinion thrust bearing. I don't recall ever seeing an explanation of what the letters stand for.
Ford had a unique (non industry standard) system for specifying "Types of Steel" used in manufacturing. The letters "EE" refer to Type EE steel.
For complete details on type "EE" and all other types there is a complete chart entitled "Steel Analysis Chart" on page 204 of the book "Shop Theory" from the Henry Ford Trade School. This chart include the metallurgical composition of each type of steel used by Ford.
There is another chart for bronze used for bushings.
Ron the Coilman
And this is from earlier post a few years ago by Trent Boggess, very useful info on "EE" steel.
John Wandersee was either the second or third man hired at the Ford Motor Company, in fact he work for Ford before it became Ford Motor Company. About 1907 C. Harold Wills told Henry Ford that they would need a trained metallurgist to help maintain quality control of the new chrome vanadium steel they were developing and which became famous with the Model T. Here is what Wandersee had to say about chrome vanadium steel in axle shafts in his Reminiscences which are in the Benson Ford Research Center:
“All during this period from 1908, when vanadium had been perfected in the heat treat process to be used in the Model T car, we were experimenting constantly on metals. On a lot of parts, like axle shafts, we got much better service and life on the manganese carbon steel properly heat treated than you would get out of a fancy alloy steel. For instance, when we were using chrome vanadium steel for the rear axle of the Model T car, after we had about 10,000,000 cars on the road, you could driver from here (Highland Park) downtown (Detroit) any day you wanted to and see two or three rear wheels laying on the pavement.”
“We had to stop that. We couldn’t redesign the Model T car but we had to stop that. We cut out the vanadium. It wasn’t so much cutting out the chrome vanadium as it was going to a different heat treat. We devised by proper analysis manganese carbon steel and then heat treated it to give us the designed results. We just dried up everything. We dried up our rear axle trouble and our crankshaft trouble. We had a lot of crankshaft breakage. We substituted manganese carbon there too, properly heat treated.”
The manganese carbon steel that Wandersee refers to is Ford Type EE steel. Most of you already know that the EE steel crankshafts were the best Model T crankshafts Ford ever made, and are highly sought after today.
According to Shop Theory The Henry Ford Trade School, the specifications for Type EE steel are as follows:
Manganese .70 - .90
Silicon .07 - .15
Phosphorus .03 max
Sulfur .05 max
Each part drawing in addition to the type of material used, will list a heat treatment code if steel is used. The heat treatment codes are located in Acc. 1701 in a section devoted entirely to heat treatments in the stacks at the Benson Ford Research Center. If you order a rear axle drawing, you should also ask for By the way, vanadium steel axle shafts made after 1919 have the name Ford in script stamped into the keyway. On EE steel axle shafts, Ford is stamped on the rough un-machined area between the two bearing surfaces. It can sometimes be hard to find.
The change to type EE steels appears to have started during 1926. Type EE steel crankshafts start to appear after July 1926 so they are mostly a 1927 model year feature. In addition to the crank and axle shafts, even the drive shafts were changed to EE steel as well.