The Caterpillar DW10 scraper

The Cat DW10 was the second article of mine that was published in Contractor, in June 2002, and was a single page offering with only a couple of photographs. In the intervening years I have uncovered a lot more information (and photos) of the DW10 making it high time to revisit this charming little motor scraper.

Caterpillar missed a golden opportunity when it rejected Robert LeTourneau’s ideas for a motor scraper in 1937.

It took it well over a decade to catch up properly, and by that time there were other competitors in the marketplace vying for sales.

The first DW10 (1N series) was introduced in 1941, powered by a 90 horsepower Caterpillar D468 diesel engine with the exhaust exiting the machine under the body like a truck.

It featured a 5-speed direct drive transmission and vacuum operated Bendix brakes and was very stylishly art-deco in appearance with lots of sweeping curves and the headlights faired into the front fenders.

The 1N series DW10s did not have rear fenders though.

Cat did not manufacture a scraper for this machine, instead leaving it up to LaPlant-Choate and LeTourneau to supply suitable equipment and the controls to operate them.

LaPlant-Choate supplied the CW-10 “Carrimor”, a 10 cubic yard heaped hydraulically operated scraper and LeTourneau offered an adaptation of its model LS “Carryall” (the model DLS) cable controlled scraper which held a similar yardage.

Less than twenty DW10s were delivered with the LeTourneau “DLS” combination.

Although Caterpillar did not build its own scrapers at this point, it did manufacture a bottom dump wagon for use with the DW10 known as the W10 Wagon which held 11 cubic yards and was hydraulically operated.

World War 2 restricted production of the DW10 as plant capacity was turned over to the manufacture of much-needed track type tractors and munitions for the war effort.

As war restrictions were being lifted, a revised version of the machine, the 6V series, was released in 1946.

This was also powered by the D468 engine, now rated at 100 horsepower.

Some modifications, brought about by operational experience and manufacturing efficiencies, were incorporated into the 6V series DW10.

These included the removal of the headlights from their faired position in the front of the fender to a headlamp placed on top of it on a bracket and the introduction of rear fenders to protect the operator from flying mud and debris thrown up when driven at speed.

The vacuum brakes were deleted, replaced by a full air braking system.

Trailed equipment was now limited to the LaPlant-Choate CW10 scraper (as Cat had cut it’s ties with LeTourneau in 1944) or a revised version of the W10 wagon which now held 14 cubic yards.

Not a great many 6V series DW10s were manufactured before the type was replaced by the final version, the 1V series, in 1947.

Now the 1V series DW10 was quite a different beast to its predecessors and for the first time featured a scraper of Caterpillar’s own design, the No 10.

It also had a new engine, the 115 horsepower Caterpillar D318 which had a larger bore and more torque than the D468 used previously.

Design-wise the machine was very different from earlier models as well.

Gone were all the clean curves replaced by a chunky, matter of fact looking machine with an exhaust pipe projecting through the hood.

A change was made to the transmission early in production to strengthen it against the increased loads imposed by the new engine.

The No 10 scraper, which was basically a Caterpillar No 70 towed scraper fitted with rear brakes, had a rating of 7 cubic yards struck and 9 cubic yards heaped and was all cable controlled by Caterpillar’s own No 21 double drum Power Control Unit (PCU).

Features of the No 10 scraper included its eccentric cantilever rear stub axles, not supported on their outside, which could be adjusted for odd sized tyres, and the curved cutting edge, similar in design to the LaPlant-Choate CW10, which the No 10 replaced.

A major revision to the scraper in 1952 saw the capacity increase to 8.7 yards struck and 11 yards heaped and the replacement of the adjustable rear axle with a straddle mounted type and a switch to a straight three-piece cutting edge.

The apron sheave tower was also opened up which allowed easier access to the apron cable for reeving.

These modifications were also applied across the entire range of Caterpillar’s towed scrapers as well.

Design of the No 10 Wagon remained unchanged.

The DW10 remained in production until 1954 when it was replaced by the slightly larger and more powerful DW15.

Interestingly, for a period after the DW15 had been introduced, the No 10 scraper still remained available for use with the new DW15 tractor, no doubt to use up old stock.

The New Zealand Connection

Only two DW10s were imported into New Zealand by Caterpillar dealer Gough, Gough & Hamer.

These were both later 1V series machines with No 10 scrapers and originally supplied to W. Stevenson & Sons.

Stevenson used them for general earthworks contracts and later, in the early stages of opening up the Kopuku opencast coalmine in the Waikato.

Both had been disposed of by the mid-1960s.

At least one of the tractor units still remains intact in the hands of a private machine collector.

For The Diecast Model Collector

At the time of writing there has been only one model of the Caterpillar DW10 produced.

This was a promotional model to 1:24th scale by Reuhl of the United States and was used by Caterpillar dealers to promote the benefits of the machine to prospective customers.

The model was diecast and represented a later model 1V series DW10.

For the day this was a very well produced model with a number of working features including the bowl, apron and ejector.

It is highly sought after by collectors and Cat enthusiasts alike.

But the model is now rare – it was discontinued in 1955 – and a good specimen will set you back well over $1500 NZ dollars.

Reuhl also offered the rear portion, the No 10 scraper with a two-wheeled dolly marketed as a Caterpillar No 70 towed scraper.

These are also quite rare.

Brief Specifications – 1952 Caterpillar DW10 (1V series)

Engine:            Caterpillar D318, 4-cylinder, inline, naturally aspirated diesel engine rated at 115 horsepower at 1800 rpm

Transmission: Caterpillar 5-speed, constant mesh with 15” double plate clutch

Top Speed:     23 mph

Tyres:             Front: 12:00×20, 14 ply

Drive: 21:00×25, 20 ply

Scraper: 21:00×25, 24 ply

Steering:          Manual worm & recirculating ball with hydraulic booster

Turning Circle: 35’

Brakes:            Full air operated expanding shoe type on drive and scraper axles

Capacity:        8.7 cubic yards struck, 11 cubic yards heaped

Control:           All cable controlled via Caterpillar N0.21 PCU

Length:            37’ 6”

Width:             10’

Height:                        6’ 4”

Operating Weight: 15.5 tons (empty), 29½ tons (loaded)

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