A tractor scatchbuilding project in large scale
Back in the early part of the last century steam power was grudgingly giving way to internal combustion. Unlike today where there are just a few small firms building equipment, there used to be hundreds of smaller, regional makes. This is a model of one of them. Kinnard & Sons, later Kinnard-Haines, of Minneapolis, Minn. built a range agricultural implements that they called "Flour City" line. From 1909 to 1927 they built 5 models of simple robustly designed tractor in 4 sizes. Only about 25 of these tractors still exist, and today are highly prized by collectors.
The 12-24 Junior
Belt Pullley..................26 x 71/2 in
Front Wheels.............................. 38 x 5 in.
Traction Wheels...........60 in., Face (R-12 in., L-14 in.)
Length.........................................152 in.
Width..........................................84 in.Wheel Base..................................92 in.
The 20-35
Belt Pulley .............................................................................. 26 x 8
*Traction Wheels .................................................................... 6 ft. x 18 in.
Front Wheels .......................................................................... 42 x 8
Wheel Base ............................................................................ 9 ft.
Width Outside Trac. Wheels ................................................... 80 in.
The 30-50
Belt Pulley .............................................................................. 32 x 9*Traction Wheels ................................................................... 7 f t. x 24 in
Front Wheels ......................................................................... 48 x 9
Wheel Base ............................................................................ 11 ft.
Width Outside Trac. Wheels ................................................... 96 in.
The 40-70
Belt Pulley......................... 34 x 10*Traction Wheels .................................................................... 8 ft. x 24 in.
Front Wheels .......................................................................... 48 x 10
Wheel Base ............................................................................ 13 ft. 6 in.
Width Outside Trac. Wheels ................................................... 111 in.
The 40-70 Special road tractor
The following is my build log of the 40-70, in approximately 1:22 scale, including catalog and restored tractor pictures used for reference to help others build their own model Flour City tractor.
Step one: the frame-
The prototype frame is made from I-beam and angle iron. For modelling purposes we can easily substitute either styrene or brass. I chose to use styrene, Plastruct brand, because it was available locally. The I-beam is 5/16", the angle 3/16" and 1/8". The length of the main sills are 7-1/4" the length of the platform extension 2"
The front casting was fabricated from plexiglas and wooden coffee stirrers. Using the corner of the stock piece to form the diagonals saves layout time and cutting. (Note: I fixed the crooked pieces as soon as the glue was tacky enough that they would stay put.
The engine crossmembers are H-beam. I used some pieces from an inexpensive Lionel accessory casting set intended for use with o-scale trains. (Please note: there should only be three of these, not four, I chose not to correct my mistake on this model, but will on the next one.
My crossmembers are simplified. The following pic by Mr. Bruce Flatmoe of his 40-70 under restoration shows the proper shape. This won't be the last corner I will cut to ease construction.
Back to the front end again, another picture of Mr Flatmoe's tractor for reference--
The pedestal is a smokejack casting, again from the Lionel set. another simplification, the decking, wood coffee stirrers from the local convenience store.
Step 2: The wheels-
The rear wheels on the 40-70 are eight
feet(!) in diameter and 2 feet wide with 32 spokes (2 rows of 16 each).
To make these, I used 4" pvc drain pipe (4-1/4" in diameter), 7/8"
'old-fashioned' wooden spools from the local craft shop, and 1/8" x
3/32" strip basswood to make them.
laying out the spokes- 
Painting the inside parts before assembling the second row is easier than trying to wedge a paintbrush between the spokes!
Rear wheel assembly. The gears are E-flite EFLH1453 Main Tail Drive Gear B400 ($3.99 ea). The design is all wrong, but spoked gears the same size were $14 apiece!
The front wheels are made the same way using 2" pvc pipe (the wall is a bit thick, copper or brass would be better if you can find it!) with a 5/8" spool for a hub. The prototype has either 14 flat spokes or 18 round ones. My model has 16 flat spokes simply for ease of layout.
Step 3: The front axle-
a couple wood wheel pegs, a piece of square plastic tube (3-7/8" long), a few bits of channel, some bent wire, and a 1/4" flat washer.
On to page 2
a couple wood wheel pegs, a piece of square plastic tube (3-7/8" long), a few bits of channel, some bent wire, and a 1/4" flat washer.
On to page 2