Those of us who own Model “M” Tractors with serial numbers prior to 52542, are unable to get assembly date or other information on them simply because no information is available. About ten years ago, I wrote to Deere & Company to try to get a build date for my tractor. I received a nice reply that stated that no records were available for my tractor, but that it was “built sometime between 10-31-49 and 11-05-50.” While knowing the build date is far from the most serious problem imaginable, it does add to the fun of collecting if more precise information can be obtained.

By studying the casting date codes that are located on many cast iron parts, I believe that an assembly time frame accurate to within a couple of months can be determined, and most dates can be ruled out. And, by studying casting date codes, it may even be possible to establish the model year of a tractor whose serial number plate is missing. The information that follows may not apply to the 1947, 1951, or 1952 model years, as I had no chance to study tractors built those years. But, that still leaves quite a few tractors to which it will apply.

Photo #1 shows the left side of the center frame of my 1948 Model “M”. Just below and to the right of my thumb, note the slightly raised area with a rivet head on each end (the M61T is the casting number of the center frame, and has no bearing on the date).

Photo #2 is a close-up of the area of interest. The casting code is 8/26B, which can be interpreted as the eighth month (August). The 26 is the day of the month, the letter “B” is for the year 1948, the second year of Model “M” production. Now we can begin to narrow down the build date; the tractor could not have been built before August 26, 1948. The serial number for this “M” is 24109.

The first serial number for 1949 is 25604, which places this tractor fairly late in the 1948 model year. However, a closer date can be found by checking the casting dates of other parts. There are five more parts to give a better clue, plus the dates on the starter, generator, and distributor. More on those codes later.

Photo #3 is the casting date of the cylinder block. It’s located just below and to the left of the carburetor and behind the lower water hose, and it’s difficult to see. This casting date is 9/15B, which is September 15, 1948, meaning the engine could not have been built any earlier than this date. Note: The engine serial number is located on the other side of the block and is stamped, not cast.

The other casting dates for this 1948 “M” are: Transmission case, 9/8B, located on the left side; righthand final drive housing, 9/14B, located below the seat frame and seen from the rear of the tractor; left-hand final drive housing, 9/17B, located below the seat frame and seen from the front of the tractor. Insofar as I can determine from the tractors I’ve looked at, “B” is for 1948, “C” is 1949, and “D” is for 1950. It would be logical to assume that “E” would be 1951, and “F” for 1952, but I cannot say that for sure.