This is another model built with my 1930, red and green, outfit No7. The origins of this model SML6a Stiff Leg Derrick date back to 1929 when Meccano introduced their superb vertical steam engine. Included with the engine came a 20 page manual (shown top right) with illustrations for thirty two models using the engine. The two most outstanding models were a Mechanical Digger and a new version of the SML 6 Stiff Leg Derrick.  Full instructions for these it stated could be obtained from your Meccano dealer or direct from Meccano, Binns Road, Liverpool price 2d (1p) each. For some reason lost in history, the instructions for the Stiff Leg Derrick were never published by the company there was just one picture and a list of the parts to guide the would be builder. (shown below left) Meccano enthusiasts had to wait until October 1973 for full illustrated instructions when Meccano guru the late Bert Love published his own instructions in the Meccano Magazine Quarterly. Of great help to me was also an article published in The Sheffield Meccano Guild Journal June 2018 by John Bader who has also built the model. Not having the funds for an original Meccano steam engine I have used a recently purchased Kleinemeier Vertical Engineers Engine this is very similar in size and style to the original Meccano engine.The gear box used on the SML 6a crane is both neater and more compact than on the original SML6. The three operations slewing, luffing the jib and hoist are carried out by sliding gears to engage with the drives from the engine. When not running the engine it is essential to have the option of hand operation this I have done with a crank linked to the main drive. The triple-reefed pulley blocks make hand operation a very slow affair. Other changes I made to the instructions are (1) 2" pulleys with tyres under each corner to give greater stability. (2) An extra rod added below the winding drive shaft to clear the rear drum cord from catching the front drum, as a result of this I went back to the double flange wheel guides at the foot of the mast as in SML6. (3) Ratchet wheels and pawls on each winding drum for braking.(4) Modern black plastic spacers instead of washers for spacing on the pulley blocks. Page three of the Steam Engine manual shows the crane lifting 56lbs (25.4kg) of type metal (a lead alloy) this picture was also used in Meccano publicity. Clearly with all the gearing and triple sheaved pulley blocks it can lift a lot of weight. I have not tested this! Its a simple model and a quick build and I was very pleased with the model when completed it looks good in 1930’s dark red and green colours set off by the brass engine. The red triangular plates are perfect on the pulley block, note the use of moderen plastic spacers. Trivia The SML6a was not the first of the Derrick cranes to feature a new power unit, the original instructions of June 1925 featured the hazardous but short lived 100- 230 volt electric motor introduced in February of the same year.  When published later as SML6 a low voltage electric motor is thankfully shown. When I selected the parts I discovered two 5 hole strips had already bent to the correct angle for the top of the mast indicating that the original owner had built the model, the original SML6 leaflet was with the set. In the May 1927 Meccano Magazine there was an article entitled “A 62-ton Steam Derrick Crane, A good subject for a Meccano Model.” It was certainly very inspiring and gives a good idea of what these cranes were like in the real world at that time. I am indebted to fellow Sheffield Meccano Guild Member John Bader for his help, advice and borowing of some ideas in building this model of a Derrick Crane. Background of the Super Models and those I have built. Page created May13 2020 Revised JUne 27 2020
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Mast and jib base
Under construction
Engine and gearbox
Triple pulley block