The Allis-Chalmers 260E elevating scraper was one of the quartet of elevating scrapers which appeared in the mid 1960s to challenge LeTourneau-Westinghouse’s dominance in the 21 cubic yard elevating scraper market. By Richard Campbell
As was the case with its rivals, the Allis-Chalmers 260E elevating scraper was based on the marriage of an existing conventional motor scraper tractor (the successful open bowl model TS-260) with an elevating scraper bowl, in this case supplied by Hancock Manufacturing of Lubbock, Texas.
Hancock invented the elevating scraper design in the mid 1950s but the concept did not catch on straight away. It gained popularity with land development contractors who found it ideal for preparing land for irrigation. These first Hancock machines were towed behind agricultural tractors.
It was not until LeTourneau-Westinghouse (Wabco) introduced a production sized machine to the market that the idea really took hold, and, in so doing, LeTourneau-Westinghouse got a great jump on their competitors who were left playing catch up for several years afterwards.
Apart from modifications to the existing scraper draft arms and a boosting of the machine’s hydraulic capacity to cope with the hydraulic elevator motor’s voracious appetite, very little had to be done to the existing TS-260 to produce the 260E elevating scraper.
Released to the construction marketplace in 1965, the Allis-Chalmers 260E sold in moderate numbers and was fairly well liked by those who had to operate it.
But the machine had a flaw, and quite a serious one: Its engine.
As fitted to the 260E, the Allis-Chalmers model 17000 diesel was at the very upper limit of its capacity in this particular application and engine failures in early machines were quite common – some with as few as 40 hours on the clock!
As a short term solution Allis-Chalmers de-rated the engine from 355 horsepower to 306 horsepower to make it live a little longer but this of course had a detrimental affect on the machine’s performance and cycle times. Allis-Chalmers then switched to the higher displacement, 300 horsepower, model 19000, diesel in 1967 and this cured the problem.
During 1968 the entire tractor unit was redesigned and made considerably more service and operator friendly.
Utilising the 320 horsepower Allis-Chalmers model 21000 engine but retaining the original Hancock elevating scraper bowl, the new 260E-A (as the machine was now known) looked quite different with its modern styled tractor unit. Allis-Chalmers sold a good number of these scrapers as by now most of the original machine’s bugs had been ironed out and the 260E-A was a reliable performer.
This machine remained in production until 1973 at which stage Allis-Chalmers undertook a complete nose to tail redesign of their entire motor scraper range. The 260E-A’s replacement was the model 261, soon to become a member of the Fiat-Allis family of machines.
Total production run of the 260E and 260E-A amounted to approximately 700 machines.
The 260E described
As mentioned earlier, Allis-Chalmers fitted early examples of the 260E with a model AC-17000, six cylinder, turbocharged, diesel engine, rated at 355 hp at 2100 rpm.
Upgraded 260Es used the 306 hp AC-19000, which was also a six-cylinder, turbocharged, inline diesel.
Attached to the engine via single stage torque converter was a five-speed powershift transmission, manufactured by Twin-Disc. This was unchanged from the type fitted to the standard TS-260 scraper.
Allis-Chalmers utilized a bull gear and pinion final drive where, by the mid-1960s, most of their competitors had moved on to planetary final drives.
The entire engine, transmission and final drive assembly was encased in a sturdy ‘tub’ which helped to maintain critical gear alignments but did limit serviceability to an extent, especially access to the differential.
Air operated shoe brakes were fitted to all four wheels.
Compared to a lot of scrapers of the period, Allis-Chalmers’ hitch and gooseneck assemblies were of a very clean and elegant design. Both double acting steering cylinders were mounted low down on the hitch and were easily accessible for servicing. A centrally mounted ‘tree’ held all the hydraulic lines that passed from tractor to the scraper and made hose changing a much easier process than normal.
The elevating scraper attached to the 260E was rated at 23 cubic yards and of typical Hancock design, with straddle mounted rear axle, outside braced bowl sides, fixed cutting edge bulldozer type ejector and a drop down strike off edge mounted to the retracting floor to maintain a nice even fill.
Mounted on the right hand side of the elevator frame was a two-speed hydraulic motor which powered the 18 flight chain assembly, turning at a nominal 256 feet per minute at rated engine speed.
For hard packed materials six bolt on teeth could be fitted to the cutting edge.
The operator was positioned just above the left front wheel well, and was provided with a torsionally sprung seat.
Allis-Chalmers used an unusual half-round steering wheel, the shaft of which bisected the two-piece instrument panel. Comprehensive instrumentation was provided for the operator so he could monitor the machine’s internal condition.
Visibility to the cutting edge was exceptional and probably the best of all the elevating scrapers in the 21 cubic yard class. All around visibility however could be classed as average – there being quite a blind spot to the operators right.
I have done a few loads in a 260E (in Australia) and found it to be a relatively smooth riding and docile beast.
A New Zealand connection
Although the TS260 conventional scraper was sold to New Zealand contractors in small numbers, I cannot find any record of a 260E elevating scraper (or 260E-A for that matter) ever being imported, either through the franchise holders CablePrice or through private importation.
New Zealand contractors were even slower than their American counterparts at embracing elevating scrapers and, by the time that the idea had really caught on in this country, the Allis-Chalmers 260E was sadly no more.
However, working examples of both the 260E and 260E-A can be found across the Tasman in Australia and over in the United States.
If there is an Allis-Chalmers 260E in New Zealand I would love to see a photo.
For the modeller
While no models have been produced of the 260E or 260E-A, a model is available of its conventional brother, the standard open bowl TS260. This was manufactured in the 1960s by Lesney (the ‘Matchbox’ people) in their King Size range and is to approximately 1:87 (HO) scale.
Even with the passage of time this is still a good little model and with a bit of effort an elevator assembly could be scratch built by the enterprising modeller and fitted to represent an early 260E.
Examples of the Matchbox Allis-Chalmers TS260 can be picked up from online auction site Ebay for very reasonable prices.
Brief specifications – Allis-Chalmers 260E (mid-production)
Engine: Allis-Chalmers model 17000 6-cylinder, inline, turbocharged diesel, rated at 306 flywheel horsepower at 2050 rpm
Transmission: Twin-Disc 5-speed full powershift with one reverse gear
Top speed: 26.7 mph
Brakes: Air operated S-cam shoe type on all four wheels
Standard Tyres: 29.5×25, 28 ply
Steering: Full hydraulic, 90° each side
Turning Circle: 33’ 4”
Capacity: 23 cubic yards
Elevator: Full hydraulic powered by vane type motor
No of Flights: 18
Maximum speed: 256 ft per minute
Length: 37’ 6”
Width: 11’ 6”
Height: 11’ 7”
Operating Weight: 29 tons (empty), 56 tons (loaded)