Image: A New Zealand- based Caterpillar 630B s/n 14G468, ex W. Stevenson & Son, fleet no.344. It is equipped with the standard 630B scraper (s/n 10G305). As can be seen, it has been sitting for some time and the elements are beginning to take their toll.
In the late 1950s, there were advances in the motor scraper industry with new innovations appearing on an almost monthly basis. In 1959, to remain competitive, Caterpillar undertook a radical redesign of its existing (and very popular) DW20G three-axle tractor scraper, writes Richard Campbell.
Somewhat resembling its DW20 predecessor, this new tractor scraper, known as the 630A (52F series), was the second in Caterpillar’s new 600 series family of scrapers (the first was the 619), and was launched in 1960.
While the 630A did resemble the former DW20, the machine was a radical step forward for conservative Caterpillar in a number of areas.
For a start, the DW20’s former D337T diesel engine was replaced by Caterpillar’s all-new model D343T diesel, a six-cylinder in-line turbocharged and aftercooled diesel featuring twin overhead camshafts. The Caterpillar D343T was rated at 335 flywheel horsepower in the 630A and was connected to a new Caterpillar nine-speed barrel type powershift transmission with a torque divider, replacing the former DW20’s manual transmission and clutch.
Another innovation was the use of planetary final drives, a first for Caterpillar on a three-axle scraper.
A considerable amount of attention was paid to the styling of the tractor unit with more flowing, rounded lines and a nicely sculpted bonnet and radiator guard.
Fenders were fitted as standard equipment to both driving and steering axles to prevent splashing the operator whose area was very neat and tidy with a full set of gauges in a well-laid out dashboard,
Caterpillar designers paying a good deal of attention to the physical aspects of the operator’s job. The old rigidly mounted DW20 operators’ seat was replaced by a shock-absorbing seat, and all controls were placed within easy reach to further improve the operator’s lot.
Steering controls were power-assisted via a Vickers steering booster, while the steering axle itself was physically bigger and stronger and had a beefier mounting than the DW20.
Brakes were air-operated shoe type on the drive and scraper axles, synchronized to brake the scraper axle first to help prevent jackknifing on the haul road (a potentially fatal situation in a machine like the 630). Ready for action, a 630A weighed 31 tons empty.
A slight drawback
With all these changes, logic would dictate that the scraper would also have had an extensive makeover, but regrettably this was not the case.
At a time when nearly all of Caterpillars competition (apart from LeTourneau–Westinghouse) had converted to full hydraulic control for their scrapers, Caterpillar was still firmly entrenched in the 1940s with all cable control.
Caterpillar offered two different cable-controlled scrapers for the 630A: initially the 27- cubic-yard struck, 35-cubic-yard heaped No.482 series C (72E series), and soon after the machine’s launch, the model 630A (60F series) rated at 21- cubic-yards struck and 28-cubic-yards heaped.
Both the No.482C and 630A scrapers featured an air-operated cable-saver device to prevent double-blocking and subsequent cable breakage.
Despite the outdated scraper technology, the 630A was well accepted by the contracting community but only sold just under 200 units in the short time (1960-1962) the machine was in production.
Realising that the slow sales of the 630A were most likely due to the lack of a more modern hydraulically operated scraper, Caterpillar hastily produced an updated version of the machine, the model 630B (14G series) – along with an all-new hydraulically operated scraper, the model 630B (10G series) which was rated at 21-cubic-yards struck and 30-cubic-yards heaped.
This appeared midway during 1962 and found immediate acceptance among machine buyers.
The 630B tractor unit featured a later version of the Cat D343T diesel, rated at 400 flywheel horsepower – a considerable increase over the previous 630A model and, of course, fully hydraulic operation of all scraper functions. A fully equipped 630B weighed almost 35 tons empty.
The Caterpillar 630B remained in production up until 1969 until the 630 series was discontinued due to declining sales.
Not quite the end of the line
There was also another version of the 630B: the model 632, which used the same 14G series 630B tractor unit, but was mated to a very large 28-cubic-
yard struck, 38-cubic-yard heaped all-hydraulic model 632 (79F series) scraper.
This machine was only in production for four years, 1962 thru to 1966 when it was withdrawn from sale, making it very rare.
Optional extras
Optional equipment for the model 630 included a reversible fan, fuel tank cap lock, parking brake, and a windscreen with wiper.
No cabs are listed for the 630A, 630B or 632 machines and ROPS had yet to appear on OSHA’s radar so there is no mention of those either.
Some ancillary manufacturers offered optional trailing units for use with the 630A and 630B tractor – most notably Athey, who produced rear dumps, bottom dumps and side dump wagons in their ‘PR’ range of equipment.
The Hyster company, better known for their forklifts and logging winches manufactured a towed double drum sheepsfoot roller for use with the 630A and 630B tractor units.
A New Zealand connection
Two Caterpillar 630A and 630B motor scrapers were imported and were delivered new to
W. Stevenson & Son of Auckland, which put them into operation at the company’s vast opencast coal mine at Kopuku, in the northern Waikato.
They were used to replace ageing Caterpillar DW20 scrapers in the coal stripping operation then, later on, in the construction of the Drury to Bombay section of the Auckland motorway system. At least one of these machines, a 630B and its scraper, has been preserved and survives. No Caterpillar 632s ever made it to New Zealand.
For the model collector
There is only one model of Caterpillar’s 630 available: a 1:87 (HO scale) example that was originally manufactured by Umex in Germany back in the 1970s (and reissued by Roco several times subsequently).
The model represents a 630A with a 482C cable scraper, but due to the age of the model and the scale, is not very well detailed. Examples appear all the time on platforms such as eBay and at local swap meets.
Perhaps someone will take up the challenge and release a decent diecast in 1:50 scale one day.
Parting words from Jeremy Sole- a final column