Forestry Memories

Chapelhall cable crane manufacture

The following was written by Jim Christie, Kinross area, who used to manage the Forestry Commission Chapelhall workshops near Airdrie.

"The change from Ford based units for cable cranes to Leyland based units with 2 speed power take offs (p.t.o.s) was not done in one step. The intermediate tractor version which I had introduced very soon after my transfer to Chapelhall is shown in the above image built in 1977. The Leyland tractor model number was 384 based on its 3.8 Litre 4-cylinder engine and this assembly happens to be the 150th Skyline built at the workshops. You will note that the equipment fitted on this machine was essentially the same as that had been previously fitted to the Fords.

Leyland also made a 344 Tractor which was required to market as a cheaper alternative to compete with other tractor manufacturer's ranges of models, but it was essentially the same as the 384 in that it had the same engine-block as the 384. Initially the 344 prototypes were down-rated by fitting a lower delivery Fuel-pump to 384s, but this made them difficult to start in cold weather so, in production they increased the compression ratio by fitting different high pressure pistons. A change to the over-all transmission gear ratio was also introduced to avoid it from competing too closely with the 384.
It was then sold at a cheaper price under the designation of 344 in spite of its 3.8 Litre engine!
On moving to Chapelhall I was able to negotiate the supply of these '344' tractors but fitted with the original 384 fuel pumps. This gave them a much higher HP since the engines also had the high-compression pistons. Critically the price agreed was as per the original 344.
At some point Leyland decided to re-name their range of Tractor models. The 344 became the 262. (2 wheel drive, 62 HP) and the 384 became the 272.They then began to develop a 2100 and 4100 both of which had 2 speed p.t.o.s. and it was my involvement in this that enabled me able to see the feasibility of fitting the 2 speed p.t.o into what was then the 262.

Below is the last model that I can give you any information about. This had the two speed PTO and carried the straw line on the drum fitted at the front to the tractor and was hydraulically driven by the standard Tractor hydraulic pump.( The tower raising ram was driven by the steering pump as explained previously)

How was the tractor raised on its jacks to allow wheels to turn to wind in cable?


The short answer to your question is -Yes, Chapelhall was using Ford Tractors as a base machine for the skylines when I took over the manager's job in 1978 after working as a Senior Design Engineer for Leyland Tractors at Bathgate.

At that time John Drummond was 'el-supremo' on Skylines and was adamant that since other companies (e.g. Jones of Larbert) were using Tractors which could send the empty carriage outwards much faster than the Ford based machines that the Commission was currently using.( This faster speed was the result of the Ford's two speed p.t.o.s,)John reckoned that our choice of base Machine should be reconsidered if we wanted to remain competitive in the out-put stakes.
While at Leyland I had been involved in re-vamping their middle range 344 tractor and also in the design of a new 100 hp tractor (Leyland 2100) which had a two-speed p.t.o.
By combining parts from both the 344 and the 2100 models I was able to write a specification for a "not for production" model that resulted in a more powerful version of the standard recently re-vamped 344 but with a 2 speed pto.
I approached Leyland, pulled a few strings, and they agreed to build us these 'Specials."

On delivery to Chapellhall workshop an adapter plate had to be built-in. This was manufactured by Chapehall and required the removal of the rear-end of the gear box in order to fit it.
One other change had to be made by Chapelhall and was required to make the tower power up and down. This simply involved in putting a diverter valve in to the power-steering circuit to supply the necessary pressure to the lift ram, and since there would never be an occasion when both these functions would be required at the same time this presented no problems.

Hope this is helpful.

Jim Christie 2019"

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Groups: Timber harvesters, processors, forwarders and cable cranes

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