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Derrick crane built for the Spanner II Christmas challenge 2010
For the past few years the Internet Meccano e-mail list, Spanner II, has run a Christmas challenge. This year the rules of the challenge are simple; to make a model using no more than 30 parts excluding nuts, bolts, washers, spring clips and cord. After a few false starts and lots of deliberation I decided to build a small Derrick crane, the result can be seen here. Small parts will eat away at the total so things such as pulleys and axles are substituted with stacked washers and bolts respectively. Brackets need to be used sparingly as these can easily use up the parts count. lots of the parts in the crane are angle girders, this saves using lots of brackets. The ball thrust baring complete, although made up from three pieces, is counted as one part as it is listed under one number (P/N 167) as a complete item. Crank handles are held in place with washers and spring clips. Spring clips are also used to secure the winding the luffing cords to the cranks. Pulley blocks increase the luffing power – utilising these helps to keep the parts count to a minimum. Slewing is a manual process!
The model works reasonably well although is a bit front heavy. This is always a problem with Meccano Derrick cranes as the prototype was always tethered. My large Derrick crane, I built last year, was also front heavy and had to be clamped to the table at shows to prevent it being accidentally toppled, but that did have a few more parts in it! I am pleased with this little model. I do enjoy a challenge as I usually end up building something I would not normally entertain – this time was different – I do like a nice crane, when Sue lets me build one! Talking of Sue… What are you building? My model has string…
…but it is not a crane! Leave him alone for five minutes and he is back in the hook draw planning to build another crane. Oh well, let me see, 30 parts… Have you ever looked at the modern corner bracket (P/N 133b)? we have nicknamed them ‘Wellie boots’ but the red ones also remind me of a Christmas stocking. My model is of a fire place with a garland of Christmas stockings hanging from the mantelpiece. The model contains exactly 30 pieces. The mantelpiece and grate used 23 pieces and the ‘glowing embers’ all 7 of them (red plastic spacer washers) made up the balance. The coal is black bolts and they don't count! Sue. |
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The first attempt at building the Derrick worked out to be 31 parts. Substituting the pulley in the hook block with a lamination of large and small washers rectified this. The same method was adopted to provide a pulley at the top of the jib for the hoisting cable to run over. Long bolts make the pivot points top and bottom of the central tower.
