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Caving Report No 3

The Manufacture of Lightweight Caving Ladders

 

by B.M. Ellis - May 1958

Introduction.

During March 1956, one hundred feet of lightweight caving ladder were made; first a ten foot length which was tested under severe conditions to ascertain the suitability of the method used, then one twenty and two thirty five foot lengths these lengths being regarded as the most suitable for use in Mendip caves. This report deals, in detail with the method used in the construction of these ladders.

Detailed specifications will be found in later sections of the report, but the main specification of the ladders is:

Overall width of rungs     6"
Distance between wires  5 ¼"
Distance between rungs 10"
Method of rung fixing      Taper Joints
Method of ladder joining  "C" rings

The author's reasons for deciding on this method of ladder construction will be found at the end of the report. The method of rung fixing by the use of taper pins is not claimed to be original; the author copied the idea from the Westminster Speleological Group ladders that he had used for many years and found to be very satisfactory. On checking these W.S.G. ladders after several years of service no case of rung slip was found to have occurred, nor had any damage been caused to the wires by the method of rung fixing employed.

The report is divided into seven sections under the headings given below:-

  1. Materials required, their suppliers, specifications and cost.
  2. Preparation of materials carried out prior to assembly.
  3. Method of assembly of the prepared parts.
  4. Details of the jigs used.
  5. Approximate times involved in the different stages of manufacture.
  6. Tensile strengths, weights and bulk of the ladders
  7. Conclusions.

The March, 1956 prices of materials are quoted as a guide some of these prices fluctuate, especially that of aluminium alloy tubing. Names and addresses of suppliers are also given for reference. All these suppliers are recommended as being quick and helpful.

Let it be said, though probably unnecessarily, that the author is not an engineer but he did have the advice of one.