Massey Harris Model 20 Combine

May 2012 026The Model 20 was introduced in 1938 making 2013 the 75th anniversary of this design, the first commercially successful self propelled combine.

In 1911 Massey Harris (MH) recruited an Australian engineer, Tom Carroll, a specialist in harvest machinery. Mr. Carroll worked upon the MH Model 1 a stripper type combine and when this proved less than successful he helped redesign the MH Model 3 combine. In 1917 he had progressed to the MH Model 5.

By 1936 Mr. Carroll had come to believe in a self propelled combine. Mr. Carroll was aware of the Sunshine Combine produced in the 1920s by the Taylor McKay Company of Australia which Massey Harris had done business with and owned a part of. As well, Mr. Carroll had seen in Argentina pull type combines that had been converted to self propelled machines.

Mr. Carroll had an ally in MH’s newly appointed General Manager, James S. Duncan who readily agreed to allow Carroll’s design team to work on a self propelled combine design. In 1938, eight pre-production prototypes were delivered to farms in Argentina for a field test program. Feedback on their performance was so positive that production was authorized immediately with new combines being delivered to customers early in 1939.

The Model 20 was equipped with a 16ft table which was wide by 1930’s standards. More importantly the machine was equipped with a 37 inch cylinder which gave good capacity for the time. The layout of the MH-20 was similar to a modern combine. The operator station was right of centre of the machine, just behind the table which gave an excellent view forward. The table could be equipped with a pick up or a knife and reel making the machine capable of straight cutting given proper crop conditions. The grain tank was behind the operator position on the left side of the machine. The MH-20 was built on a steel girder chassis and was powered by a Chrysler six cylinder truck engine. This engine and some driveline components were used in some models of MH tractors. The engine was hung out on the right side of the combine where it was accessible but exposed to the elements.


While the MH-20 was heavy and expensive, it was popular with customers who were pleased with its maneuverability and capacity. Sales of the MH-20 totaled 925 machines over two years, 1939 and 1940. The Model 20 was succeeded by the Massey Harris Model 21 which sold in the thousands giving MH a majority share of the rapidly emerging market for self propelled combines.


Tom Carroll’s role in the success of the MH-20 was recognized with the award of a Gold Medal in 1958 by the American Society of Agricultural Engineers to recognize his contribution to combine development. Along with the first successful self propelled combine, Tom Carroll helped introduce to the farm machinery business mechanical improvements such as welding, roller chain, oil bath gear sets, ball bearings and detachable tables which made combines easier to transport.


The MH-20 in operating condition in the Museum collection comes from the Westwood Family of Rapid City, Manitoba. Mr. Harold Westwood, who farmed in the Rapid City area and operated the Massey Harris dealership in the town of Rapid City, purchased the combine new in 1938. Harold farmed through the 1950s and sold the combine to a nephew sometime in the early 1960s. The nephew used it for a few years and then parked the machine. Harold’s grandsons, Allan and Laurence Westwood, purchased the machine in 1983 and returned it to operating condition. The machine was donated to the Museum at that time.

The Expo at the 2013 Threshermen’s Reunion features the Massey family of companies. If you have equipment built by Massey Harris, Sawyer Massey, Massey Harris Ferguson, Massey Ferguson or any of the firms purchased by the Massey family such as Wallis or Wisner, you should consider bringing it to the Massey Expo. You can contact the Museum office at 204-637-2354 to make arrangements.

The Museum is open year round and operates a website at which can provide visitors with information on Museum events and location.

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