First page of the original instructions from the Meccano Magazine

Motor, twin out put gear box and hoist drives for jib and bucket.

Cab during construction I have since added a second sliding door.

One of my favourite features in the Meccano magazines from the mid 1950's was the "Model of the month" brief instructions and photographs were published in the magazine, duplicated more detailed instructions could be obtained free of charge by writing to Meccano Ltd at Binns Road Liverpool. The full series are available from MW Models in printed or digital format.

This well proportioned model of a Mechanical Excavator was originally published in June1956. At the time parts were finished in red and green but I thought the excavator would look attractive in yellow and zinc parts, these primarily were taken from my 1973 Number 10 Outfit. Please note additional parts to those in the number 10 set were required. I followed in principle the original plans but made a number of changes. I must say the photographs and building instructions are somewhat lacking with over use of the the phrase "can be seen from the photograph", which was probably fine if viewing the original photograph .

Fellow enthusiast Norman P. Brown has also built this model using red and green parts, his pictures shown on the NZ Meccano Gallery were an invaluable source of reference during construction. I changed the gearbox as he had done for a neat twin output version with forward neutral and reverse. This was designed by F. C. Dolman and had been described in the February 1968 edition of the Meccano Magazine. The gear box has the big advantage of using worm gears for the output giving braking when the drive is in the neutral position.

The original model specified the use of an E15R motor and a complicated reduction gearing I used a Meccano PDU with a rubber belt drive to the gear box.

After completing the construction of the rotation bearing as bearing described in the instructions using four brass, ½" pulleys these were over stressed by the weight of the superstructure. I had rethink and rebuilt it using a Märklin 80mm Hub Disc with ten ½" plastic pulleys this made the superstructure firm and stable.

One problem I encountered when using the zinc 19 hole girders for the bucket arm was that the steel used was slightly thicker than earlier painted parts and was a very tight fit between the jib girders. I overcame this by building up a compound arm from shorter girders which were of thinner steel.

At a late of construction stage I found it necessary to carry out a further modification to the hoisting and digger operating cords. The drives and motor were under some strain due to a lack of torque as the jib was raised I overcame this by lifting the initial lift pulleys higher in the cab. This change is shown bottom left.

Shown below is a Priestman digger from the nineteen fifties possibly the prototype for the Meccano model .Picture is shown courtesy of FreeFoto.com

Page created March 27 2014 revised October 06 2014