Manufacturing Corporation produced a variety of tractor models from
1946 to 1952, including the Model A, the D Series (D, SD, Super D and
Super D2), the E Series (E, EF, EW and EWF), the Super G (only one
built), the H Series (H, HFS and HFA), the I Series (I, IFS and
IFA), and the M (only one known--possibly a prototype).
A. Gibson founded the Gibson Manufacturing Corporation in Seattle,
Washington, in 1933, to build railroad cars to transport loggers and
supplies to and from logging camps. The company decided to capitalize
on the demand for tractors after World War II, and it began to build
small tractors as a sideline during slack periods. The Gibson trademark
was registered in 1943.
workers threatened to unionize, Harry’s son Wilber F. Gibson moved
tractor production to a new factory in Longmont, Colorado, in 1945. The
move may also have been motivated by the need for a more centralized
location for sales and distribution. Tractor production continued in
Seattle for a period after the plant was opened in Colorado.
March 2, 1946, The Longmont Times-Call reported: "Fifty-two small farm
tractors went off the assembly line at the Gibson Manufacturing
Corporation this week as the company went into production. The first 16
tractors left by truck and trailer for Denver, where they were
consigned to tractor dealers. Distribution of the remaining 36 will be:
ten to Boise, Idaho, ten to Salt Lake City, Utah, and a rail carload to
Phoenix, Arizona." These tractors were Model A tractors--the first
model produced by the Gibson Corporation.
Model A had a 42-inch wheelbase and weighed 875 pounds. The tractor was
powered by a one-cylinder, 5.9 hp., air-cooled, AEH Wisconsin
industrial engine, which was started with a rope-start. The
tractor had 4.00 x 12 front tires mounted on cast-iron hubs and 7.50 x
16 rear tires on one-piece wheels. The tractor had a three-speed
automobile transmission and an automobile differential with shortened
axles and independent, external, rear-wheel brakes. Company
representatives scavenged transmissions and differentials from salvage
yards in the Seattle area and refurbished them for reuse in the
tractors. A number of tractors were issued with Chevrolet transmissions
and Plymouth differentials; however, others were used as available,
including Borg-Warner T-96 transmissions--the same as those used in
Willys Jeeps, AMC, Crosley, Ford-Falcon, and Studebaker automobiles,
and Economy Power-King garden tractors, amongst others.
used automobile parts was a practice adopted by a number of garden
tractor manufacturers at that time, and it usually resulted in durable
and reliable tractors which were often overbuilt. At one point, Harry
Gibson was sued over a company claim that Gibson tractors were built
with all-new parts. The end result was that Gibson tractors varied one
from another, depending on what parts were available at the time.
built in the Colorado plant continued to have automobile transmissions,
but differential housings were specifically cast for the tractors. The
Longmont housings had "Seattle, Washington," cast in raised letters on
one side of the axle tube and "Longmont, Colorado," on the other. The
clutch consisted of a V-belt-tightening mechanism (4 A-belts), with a
chain-drive to the transmission. The Gibson Company claimed that the
Model A could pull a 13 1/2-inch plow and plow two to three acres in a
10-hour day, with fuel consumption of 1 1/2 quarts per hour. The Model
A had neither hood (engine cover) nor fenders; it was steered with a
tiller (lever) on the right side. Early Model A's were painted Ford
gray, with yellow trim. Later Model A's were painted Wisconsin gray.
Standard equipment on a Model A was a front blade raised and lowered by
means of a lever on the left side, towards the front, and an adjustable
hitch, raised and lowered with a second lever on the left side, near
the rear. Approximately 500 Model A's were built in 1946.
Model D was the second tractor produced by the Gibson Corporation. It
was four inches longer than the Model A, with a wheelbase of 46-inches;
it weighed 955 pounds. The Model D had 4.00 x 12 front tires. Early
tractors had 22-inch rear tires mounted on one-piece rims and centers.
Later Model D's had 24-inch rear tires mounted on detachable rims--the
same size rims and tires as those on Farmall Cubs. The rear wheels were
adjustable from a minimum tread width of 33-inches to a maximum width
of 54 1/4-inches.
early Model D's were powered by one-cylinder, 9 hp., air-cooled, AHH
engines started with hand cranks; most Model D's utilized the same 5.9
hp. AEH Wisconsin engines used on the Model A. The Model AEH engine was
started by wrapping a rope around a pulley mounted on the end of the
crankshaft and pulling. The Model D also had the same lever (tiller)
steering, V-belt-based clutch, and automotive transmission as the Model
A. The three-speed transmission produced forward speeds of 2, 4, and 7
mph.; reverse moved the tractor at 2.5 mph.
differential housing on the Model D was cast iron and produced
specifically for the tractor; like those on the Model A, each
axle-housing had "Seattle, Washington," in raised letters on one side
and "Longmont, Colorado," on the other. It has been reported that the
differential gears were the same as those in a Chrysler automobile,
but this has not been confirmed. Like the Model A, the Model D did not
have a engine cover (hood); however, fenders were optional. Although
rope-start was standard; a starter-generator system was optional. The
Model D was outfitted with the same front blade and adjustable hitch as
the Model A.
Model D's were painted Ford gray; later ones were Wisconsin gray. Front
and rear wheels were red; the rear rims were steel colored. The Model D
sold for $545, and it was produced from 1947 to 1949. Implements
available from the Gibson Corporation for its tractors included a plow,
cultivator, disc harrow, snow plow, angle dozer-blade, spring-tooth
harrow, and sickle-bar mower.
Model SD was basically the Model D, with the addition of hood, grill,
and fenders. The Model SD retained the lever steering used on Models A
and D. The Model SD weighed 1,065 pounds. Electrical and hydraulic
systems were options.
all owners/operators of Models A, D, and SD were pleased with lever
steering. It was not unusual to have these tractors modified locally
with automobile steering wheels and gear boxes; those from Volkswagens
Super D retained the features and options of the Model SD, including
the single-cylinder Wisconsin AEH 5.9 hp. engine. It was the first
Gibson tractor factory-equipped with a steering wheel. It weighed 1,105
Super D2 continued many of the features of the Super D; however, it was
the first Gibson tractor powered with a two-cylinder engine--the 12
hp., Model TF Wisconsin, L-head, air-cooled engine. The Super D2 had a
52-inch wheelbase and weighed 1,375 pounds.
Gibson Corporation touted Models Super D and Super D2 as having
"...simplicity of design and construction--your assurance of
long-lasting and trouble-free operation."
Model E was larger than the Model A or any of the Model D Series
tractors. It was powered by the same two-cylinder Model TF Wisconsin
engine used in the Super D2 tractor. Early Model E tractors had tiller
(lever) steering; most were issued with steering wheels. The steering
wheel was offset to the right side, and it reduced the
operator's visibility on that side. The Model E was available in four
versions; the basic Model E, a row-crop (tricycle) configuration; the
Model EW, a row-crop (tricycle) configuration with wide rear-wheel
adjustment; the Model EF, a standard four-wheel configuration with
front-wheel adjustment from 40 to 60 inches and standard rear-wheel
width; and the Model EWF, a wide-tread (84-inch) cultivating tractor.
The Model EWF could straddle two corn rows.
Model E was the only Gibson tractor with rear drop axles
(chain-driven). Tractors in the E Series each weighed 1,905 pounds.
Model E tractors had a rear hydraulic lift and both splined and keyed
PTO shafts on a transfer case mounted in front of the transmission. The
keyed shaft was for a pulley. Although an electrical system
was standard on most Model E's, some early tractors were issued with
magnetos and were started with a hand crank. Also on early Model E's, a
pedestal supported the rear of the hood and the gas tank; this pedestal
was initially replaced on later tractors with a sheet-metal
dashboard/firewall and finally with a cast-iron dashboard/firewall.
With the addition of side panels and decals, Model E tractors were
similar to the larger H and I models which came later.
from Model I on were full-sized tractors with four and six-cylinder
engines. Row-crop models, adjustable front axles, tire options, and
electrical and hydraulic systems were available in later tractors.
Model I Series was made up of the Model I, a row-crop (tricycle)
tractor; the Model IFS, with a standard fixed front axle, and the Model
IFA with an adjustable front axle. A six-cylinder ZXD Hercules engine
powered Series I tractors. The tractors had a 94-inch wheelbase, 5.50 x
16 front tires, and 10 x 38 rear tires; they weighed 4,000 pounds each.
A Model I was texted at the Nebraska Test Laboratory in May, 1949 (Test
# 408), and it was rated at 39.5 hp. (belt-hp.).
photograph of a Gibson Model M exists. However, nobody has gone on
record as owning such a tractor, so it might have been a prototype
which never made it into production.
Model G was believed to be the last Gibson tractor built by the Gibson
Corporation. Only one Model G tractor is known to exist, and it was
Wilbur Gibson's personal tractor. Mechanically, the Model G was
identical to the Model I. It weighed 4,512 pounds and was priced at
$2,170. The Model G varied from the Model I in that it had a higher
driver's seat, a steering wheel that was angled rather than vertical,
chrome trim, and a hood that could be raised to facilitate service.
Model H Series consisted of the Model H, a row-crop (tricycle) tractor;
the Model HFS, with a standard fixed front axle; and the Model HFA,
with an adjustable wide-front axle. Model H Series tractors were
powered with four-cylinder Hercules 1XB engines. They had an 86-inch
wheel base, 5.00 x 15 front tires, and 10 x 38 rear tires;
they weighed 3,650 pounds. The Model H was tested at the University of
Nebraska Test Laboratory in May, 1949 (Test # 407), and the tractor was
rated as a 25 hp (belt-hp.), two-plow tractor.
50,000 Models A, D-Series, and E-Series tractors were built; less than
500 each of Models H and I were produced.
Gibson Model A and Model D tractors were painted Ford gray; later
tractors were painted Wisconsin gray. Model A tractors had yellow
wheels; Model D tractors had red wheels. All other models were red with
steel-colored rims (some Super D tractors had yellow inner rims).
two longest-lived Gibson models were the Super D and Super D2--both
being built from 1948 to 1952 by the Gibson Corporation, and then again
during the mid-1950's to 1958 by Western American Industries.
the final years of the Gibson Corporation, there were also attempts to
produce a small Model 365 mower/tractor powered by a 2 1/2 hp. Briggs
& Stratton engine, and a Gibson Country Clubber--a two-seat
golf cart powered by a two-cylinder, electric-start, air-cooled engine.
There is no indication that either vehicle was actually produced.
Production of Gibson tractors was suspended in February, 1952, and the factory closed in June, 1952.
The Gibson Manufacturing Corporation was sold to Helene Curtis
Industries in 1952, and production ceased for seven months. During that time, only parts
were available from a Helene Curtis subsidiary--the Fox Metal Company.
Production interests were eventually leased to Western
American Industries, and that firm built approximately 1,000 Models D,
SD, and Super D tractors. An advertisement dated March 25, 1957, priced
the Model D at $760, the Model SD at $810, and the Model Super D at
a serial number on a Gibson tractor can be an adventure in itself. Many
tractors had serial numbers stamped on the right frame rail--sometimes
on the end of the rail itself. However, there were
exceptions, and some owners assert that their tractors lack serial
numbers. Also, a rumor has circulated that blocks of serial
numbers were skipped, so that the company could cite larger production
figures for publicity purposes. Serial numbers usually consist of the
model letter, followed by the production number.
to a lack of company records, many questions have been raised about the
production of Gibson tractors. These include: Did any of the tractors
produced in Seattle have the cast-iron differentials made specifically
for Gibson tractors? And, conversely, did any of the tractors produced
in Longmont have automobile differentials? How many Model A's were
built in Seattle and how many in Longmont? Why were both the Longmont
and Seattle locations cited on the cast-iron differentials? How long
did tractor production continue in Seattle after the Longmont plant was
up and running?
disassociating himself from the Gibson Manufacturing Company, Wilbur
Gibson designed and produced the PowerFlex 10 Tractor in
Berthoud, Colorado, in 1958 and 1959. After Wilber Gibson died in 1959, the entrepreneur
who had financed the enterprise took over production and added
his name to the tractor. The PowerFlex 10 became the Harvey PowerFlex
PowerFlex 10 and Harvey PowerFlex 10 tractors were assembled from used
Ford truck parts and left-over
Gibson parts. The tractors had 9.6 hp. single-cylinder Clinton
Red-Horse engines, and Ford truck clutches, transmissions, and differentials. Most tractors had three-speed
transmissions with shifting levers on the steering columns; a
few were made with
four-speed transmissions and transmission-mounted shifting levers.
Apparently, the only implement made for the Harvey tractor was a front
blade. It is estimated that between 50 and 60 PowerFlex 10 and Harvey PowerFlex 10 tractors were built in 1958 and 1959.