Image: Mid-’70s-era International 412 with the optional factory cab fitted. Note that this is a soft cab, ROPS still having to make an appearance when this machine was originally delivered. As can be seen, the cab (and machine), are quite narrow, making for a ‘cosy’ work environment. Photo: Author’s collection
Released for sale in 1972, the International-Harvester model 412 found immediate acceptance among smaller contractors, agricultural contractors and building site developers. By Richard Campbell.
The model 412 was a direct descendant of International-Harvester’s previous model E200 and E211 elevating scrapers, the first of which, the E200, was introduced in 1966. The model 412 was a considerably refined offspring, featuring more options, more capacity and more power while retaining the nimbleness and versatility of its predecessors.
At only 8 feet (2.44 metres) wide, and with an empty weight of only 14 tons, the 412 was legally roadable just about anywhere, enhancing its flexibility and usefulness to potential buyers. Adding to the attractiveness of the 412, the entire machine was designed and built by International-Harvester, apart from the power shift transmission, which was supplied by Twin-Disc, making the 412 basically a ‘one-stop shop’ for parts.
The only other item not manufactured by I-H were the tyres!
Powering the 412 was an International DT-466, six-cylinder, turbocharged diesel, rated at 150 flywheel horsepower. The DT-466 engine was also used in other machines in I-H’s range, most notably as the rear engine in the models 433 and 444 motor scraper as well as some of the Hough PayLoader range, making for excellent parts commonality.
As mentioned previously, the power shift transmission was supplied by Twin-Disc and featured four forward and one reverse range, with first gear being a particularly low speed to give added rimpull when loading; especially important in an elevating scraper. Planetary final drives and a heavy-duty differential finished off the power train and permitted a top speed of up to 25 mph (40 km/h), very useful for roading the machine between jobs.
Steering was fully hydraulic using two double acting hydraulic cylinders with multiplier linkages mounted high up on the machine’s gooseneck. This arrangement permitted 90 degree turns to left and right with the added benefit that the multiplier linkage smoothed out the turns making them less jerky.
The bowl of the 412 held 11 cubic yards and was constructed of reinforced steel plate with box section gussets. This made it particularly strong and resistant to deformation in service.
The elevator mechanism employed 16 flights and was hydraulically driven from an engine mounted pump. The whole elevator assembly was spring dampened to help reduce loading shocks.
A three-piece cutting edge was used, the centre portion of which could be fitted with five teeth, if necessary, to break up particularly hard material. The cutting edge was also used as a strike off plate for levelling the fill, but this operation was a little awkward if cutting edge teeth were installed.
For ejecting the load, International employed a sliding floor with a bulldozer ejector.
International equipped the 412 with air actuated hydraulic shoe brakes on all four wheels. Tyre equipment was usually matching 23.5×25-16PR E2 tyres, but E3s could be fitted as a customer option.
The model 412 shared the great visibility the previous models E200 and E211 had and came ex-factory with an open ROPS structure, seat belt and a windshield. International also offered a ROPS cab for the 412 as a customer-specified option along with air conditioning.
Although the operator’s compartment was somewhat narrow, all operating controls were well laid out in a logical manner.
An air suspension seat was supplied for the operator (usually a Milsco), although some later models I have seen have been fitted with Bostrum seats.
A new model
Manufactured for seven years (’72–’79), the model 412 was replaced in 1979 by an upgraded version, the model 412B.
These upgrades were brought about by field experience with the original 412, the most notable upgrade being the de-rating of the IH DT466B engine to 125 flywheel horsepower, apparently to lengthen the engine’s life expectancy between overhauls. Very little else seems to have changed externally, transmission and drive train remained unaltered and cubic capacity remained the same. However, empty weight of the machine had now risen to 15 tons.
Enter Dresser
Dresser Industries Inc acquired International-Harvester’s PayLine Division (dozers, scrapers, haulers, excavators, wheels and track loaders) in 1982.
Dresser was a huge organisation, originally founded in 1928, with roots in the oilfield industry, and at one time had future US President George W Bush working for them. Dresser undertook an extensive overview of the International-Harvester product line to see what was profitable and discontinued quite a lot of the existing International models, including most of its motor scraper line.
One machine that was spared was the 412B elevating scraper, which remained in production, virtually unchanged as the Dresser model 412B until 1999 when it too was finally discontinued due to a worldwide downturn in sales of scrapers.
This is not quite the ‘end of the lesson’ however, as Dresser still had a card up its sleeve in the form of a US Army contract to supply a 12 cubic yard motor scraper for training soldiers in the use of heavy equipment.
What was different was the specification required an open bowl scraper, not an elevator. Dresser struck up a deal with the Rome Plow Company to supply quantities of its model R67H towed scraper bowls which were mated to suitably modified 412B tractor units, thereby creating a very serviceable open bowl scraper. Examples of these machines have now found their way into the public sector through Army disposal auctions.
Summary
Production of the International/Dresser 412 and 412B exceeded 3000 machines, making it the most successful (and long-lived) scraper that International ever manufactured. The machine was a contemporary of the Caterpillar 613, Wabco 111A, Michigan 110-11, Terex S-11E and Fiat-Allis 161.
For the model collector
Regrettably, the model world has not been kind to the International 412/412B as only one example, a 1:64 scale offering from Ertl, has ever been issued.
This has been released several times over the years in both International-Harvester and Dresser colours, but the diminutive 1:64 scale of the model, not to mention the rather poor detailing, precludes inclusion in any serious election of constant scale models such as 1:50.
It is to be hoped that at some stage a model manufacturer will address this oversight, as models of elevating scrapers are rare.
Parting words from Jeremy Sole- a final column