Allis Chalmers HD-10

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AC HD 10

The HD-10 was a fairly popular machine in its time. Photos follow here on three different ones. The first one is a restored model that I found and photographed sitting on a truck in Gaston, Oregon in the summer of 1998. This machine appears to be equipped with a Carco winch and an angle blade. There seems to be both hydraulics and cable on the front. I didn't walk up to the machine to see just what it did. In the past it was not all that unusual to see a hydraulic tilt blade with a cable lift, but I am not sure what I am looking at here. The canopy is sort of typical of dozers in Oregon of this era that were used for logging. Long before ROPS was invented by the Feds, all Oregon logging dozers had to have a canopy, and sweeps were required (that being the angle pipes from the front of the machine up to the roof line.) This canopy was not designed for roll over protection. Rather it was suppose to fend some of the brush off and deflect falling trees. A rear screen was provided to stop flying rigging as well. Newer safety rules have provided further protection.

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AC HD 10
This precious old machine isn't a VanNatta Machine. Rather. it is a family heirloom of Nohr Engineering . You can see in this photo a typical example of a multi-part cable control for lifting the blade. This was standard on most dozers until around 1960. A small winch spool driven off the front of the engine tended to lifting the blade. A lever controlled the lift, hold release sequence.

Once hydraulic blades became available the industry switched quickly by popular demand. Cable blades had their problems. They went down only by gravity so if the digging was hard, you had available only the weight of the blade to force it into the ground. Hydraulics first appeared on smaller dozers and grew to the largest of them. The larger dozers, of course, were more functional with the cable blade because the big blades were heavier anyway than those found on small dozers.

A universal disadvantage of the cable blade was that if the dozer ever became mired in the 'yuck' you couldn't use the blade as a 'jack' to lift the tracks out of the goo so you could throw what ever under th tracks to get your machine back up to normal ground level.

Not having seen this machine for real, but looking at the manifold in the photo, my guess is the the power unit in this dozer was a Jimmy 4-71.


Here is a photo of another HD10 that was generously furnished to me. This photo was taken around 1954, and depicts an HD10 Allis Chalmers with a Baker Dozer and a LeTourneau scraper (not shown) . Notice how crude this blade seems as compared to the blade on the Nohr HD-10 in the upper photo. ONe of the evolving things in blade design is a change in blades from a large blob of iron to a more carefully shaped cutting instrument.

However, this blade did have a modern feature which made it a forward looking blade. It was hydraulic controlled. Though not well shown in this photo, the loop over the top of the dozer behind the operator served a purpose. There were two vertical standing hydraulic cylinders which lifted the 'bail' over the dozer and thereby lifted the blade. Many of these early machines did not have enough frame or superstructure 'out front' to support the stresses of lifting the blade so on very old dozers you often see some sort of a superstructure added to the dozer to handle the lifting. Notice how this dozer has only what appears to be a sheetmetal radiator grill. .

It seems odd now, but the early engineers of these machines thought they were building a tractor to pull things, and the blades were an aftermarket idea. It wasn't until later that the manufacturers started building the things with the idea that a blade would be 'standard equipment'.

Special thanks to Elmer Anderson who provided this photo which features his father. He reports that this dozer is still running in the Toledo Iowa area.

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