Intended as a larger version of the Euclid S-7 which had proved to be extremely popular, the Euclid S-12 never really fulfilled its obvious potential. By RICHARD CAMPBELL
Back in the February 2006 issue of Contractor, we had a look at the Euclid S-12.
The original article was quite short due to allocated space limitations and in the mean time a lot more information has become available to give the machine the coverage it deserves.
Designed in 1953, the prototype was tested over a period of months at GM’s proving grounds and found to be suitable for production.
The Euclid Earthmoving division of GM had high hopes for the S-12 as its smaller sibling, the seven cubic yard capacity S-7, was selling well and making all manner of inroads into the fleets of smaller contractors.
Intended as a work-alone utility machine, or a scraper that could be used in groups for higher production, the S-12 seemed to be the ideal tool for the intermediate-sized contractor.
With a bowl holding 12 cubic yards struck and 16 cubic yards heaped, this was a useful capacity for its intended tasks.
It also filled a gap between the smaller utility machines and the larger bulk earthmovers
The production version of the S-12 was known by Euclid as the 78FOT-29SH and was introduced in 1954.
Originally delivered in dark green “Armington Green” paint, this soon gave way to the more familiar pale lime “Hi-Lite Green” which GM launched in 1955.
Unfortunately for Euclid, the S-12 was not the big seller that it had hoped.
Probably the biggest drawback to the machine’s success was that it was never issued with a powershift transmission or even a torque converter, all production models having a Fuller manual gearbox and clutch.
While this was not an issue in the 1940s, when all machines had manual transmissions, the earthmoving world had now advanced, and the S-12 didn’t really make the grade.
The new breed of scraper operators didn’t like manual transmission machines anymore.
Another issue was size.
While the S-7 was only eight feet wide and legally roadable, the S-12 measured almost twelve feet wide which meant that it had to be shifted from job site to job site by transporter, somewhat limiting its flexibility.
Why GM/Euclid never ever fitted the S-12 with a powershift transmission is unknown as the GM 6-71 powerplant used in the S-12 was already in service in other Euclid machines with powershift transmission setups and giving no problems.
Euclid manufactured just under 750 S-12s before the type was discontinued in 1965.
Production was entirely at the Hudson, Ohio plant, no S-12s being built outside of the USA.
The Euclid S-12 Described
Of conventional Euclid design, the model 78FOT S-12 was essentially a scaled up S-7.
Power was supplied by a General Motors 6-71 diesel rated at 218 flywheel horsepower.
Attached to the engine was a Lipe-Rollway 15½” single plate clutch with an air booster to make the operators day a little easier.
Transmission was a Fuller 5F1220 5-speed type giving the machine a top speed of approximately 23 mph on the flat.
Braking was provided by fully air operated expanding shoes on all four wheels.
Standard tyre was usually 24.00×25 with a rock tread.
Euclid’s steering system comprised two double acting hydraulic cylinders acting against the hitch and capable of reverse action during a full 90 degree turn for maximum power.
The 29SH scraper was also of conventional Euclid design with a roll out ejection system.
All the hydraulic cylinders used were single acting with gravity returning them to the ‘down’ position.
Twin link arms and rods connected the bowl to the lift cylinders.
Cutting edge penetration was entirely dependent on the weight of the bowl on the cutting edge, meaning that pre-ripping was usually required in harder soils.
A four-section reversible and interchangeable cutting edge was used meaning only a single person was usually necessary to perform an edge change out.
Just as a matter of interest, a spotting feature of the S-12 scraper are the lifting link arms which have a central stiffening rib above the lift cylinder mounting point. No other two-axle Euclid scraper has this feature.
The apron, although hydraulically controlled, was attached to its link arm by a length of ¾ inch cable.
It was a true radial arc design and during loading, the weight of the material inside the bowl assisted in the gravity closing.
Early production models of the 29SH scraper have holes in the rear wheel hubs (like the S-7), later versions do not.
A substantial push block brought up the rear of the machine.
For the operator, the control layout was basic with clutch, brake and throttle pedals on the floor and the gearshift stick to the operators right.
The bowl controls consisted of three levers, bowl up/down, apron up/down and ejector forward and return.
These were all directly connected to the hydraulic control valve through a short link which made for precise control.
Full instrumentation was provided on the dash panel.
Most S-12s were fitted with some form of suspension seat (there were two types) although others just had the circular sold plinth type which meant your bum did all the cushioning!
While almost in a class of its own, the S-12 did have some competition.
There were not a great deal of options available for the Euclid S-12.
A fully enclosed cab with a heater and defroster could be installed along with a windscreen wiper which was also available on those machines just equipped with a windshield.
Operationally, the scraper could be exchanged for an Easton-,manufactured 18 cubic yard hydraulic rear dump or a 19 cubic yard capacity Euclid 130W belly dumper.
Very few of these last two options left the Hudson factory, almost all S-12 production being scrapers.
The New Zealand Connection
Only one Euclid S-12 was ever imported by NZ distributor Clyde Engineering.
This was originally delivered to Burnetts Motors of Ashburton, however the machine spent most of its working life with J.C.Anderson’s of Invercargill.
The machine apparently still exists, a very rare beast indeed and worthy of preservation.
For the Model Collector.
Things are very bleak on the modeling front with no models of the Euclid S-12 available in any scale.
In light of the machines low production numbers this is probably not surprising but unfortunate none the less.
Models of Euclid machines in general are very few in number, due I’m told, to some ridiculous trademark licencing problems.
Brief Specifications – Euclid S-12 Scraper model 78FOT-29SH (1957)
Engine: General Motors 6-71, inline, 4-cylinder two cycle diesel rated at 218 flywheel horsepower at 2100 rpm.
Clutch: Lipe-Rollway 15½” single plate, air boosted
Transmission: Fuller 5F1220 constant mesh manual transmission
Top Speed: 23 mph
Brakes: Air operated expanding shoe type on all four wheels
Steering: Full hydraulic, 90° to each side
Turn Circle: 31’ 2”
Tyres: 24.00×25, 26 ply, E3
Capacity: 12 cubic yards struck, 16 cubic yards heaped
Operation: Fully hydraulic via four interchangeable, single acting hydraulic rams
Length: 35’ 3”
Width: 11’ 2”
Height: 9’ 6½”
Op.Weight: 23 tons empty, 43½ tons loaded