WORTLEY TOP FORGE MODEL ENGINEERS
Jeremy the Jeep -
By Gary Sutton
One day last autumn Bryan Donn approached me and offered to test my woodworking skills.
I have a part built Jeep that I started some years ago and it needs finishing off. Are you interested ?
I accepted the kind offer and the following week the kit arrived in the back of Bryans van.
Plans were supplied together with the MDF cut-outs which constituted the bodywork for the new baby.
On returning home, perusal of the plans left me with a number of challenges in order to complete the project. Where can I get wheels from ? What sort of motor and drive to use ?
In true Model Engineering tradition I set about collecting a kit of materials to enable the steering, drive, windscreen etc. to be constructed. Criteria were : cheap or free, readily available, could be modified from something which already exists.
In due course, the building of the bodywork began and the build rate accelerated over the Christmas 98 holidays. This consisted of screwing and gluing the MDF sections to softwood rails which reinforced the structure sufficient, eventually, to support the weight of one small boy, and / or one big one !
As the structure grew I began to realise why Bryan had decided not to complete it as the weight increased with each panel fitted. Having done sufficient to see how it would look I turned my time to acquiring the outstanding materials and re-assessing the design of some of the components.
Firstly the front axle was completed having re-designed the king pin area as I was not convinced of the benefits of the original nuts rotating around threaded bar solution.
After much deliberation, and ideas from many quarters, I tracked down a set of 4 wheels, for free, at a company which repairs wheelchairs. Great now I can build the stub axles and finish the front end off.
It was at this point that I realised how poor my welding skills had become and some of the work had to be re-done as the included welds were removed using bruit force and ignorance, as my Dad always says. However, the front axle and wheel assembly was completed and attached to the part rolling chassis, much to Marks delight. Is it nearly finished then Dad ? When can I ride in it ?. Hopefully before you leave home for University, son !
Now the drive mechanism ; chain drive was specified but I considered that the start up load, on the motor from standstill, was excessive considering the weight of the vehicle. I also had concerns about running the motor as a dynamo whilst rolling but not driving so I devised a cunning plan to start the motor in free running mode and then via a belt and jockey wheel tensioner gradually take up the drive. The jockey wheel had to be spring loaded whilst being loosely attached to the accelerator pedal.
A motor and gearbox from our old friend at Parkside was purchased and the fun began on how to harness the power from the output shaft to the single rear driven wheel. The wheels were of the 7 spoke variety, moulded from plastic and therefore having plenty of draft angle on them to enable withdrawal from the mould tool. This was certainly a challenge considering the basic workshop equipment I own.
In the end I milled 7 mating slots in a piece of 3 aluminium bar which was then bored out and the painstaking task of matching the draft angles was completed by filing.
The back axle came next and the Deep Cycle Battery was bought. It was now late March and the time had come for the first trial run. The drive seemed to work quite well but the motor seemed under powered and laboured, an issue which was later to come back and haunt me !
However, it stimulated mine, and Marks, enthusiasm that we could one day soon see Jeremy running around the Forge.
The inner and outer wings were skinned with aluminium and, for the first time, the traditional Jeep shape became apparent.
Much painting was followed by the wiring up and installation of switches to control : on / off, forward / reverse.
Jeremy was alive at last ! but the gravel drive and solid tyre combination limited Marks forays mostly to cruising around the Forge on Sunday afternoons. The school summer fayre saw Mark driving passengers around a couple of circuits of the playground, a task which was adequately performed almost non - stop for three and a half hours.
The Penistone Mayors Parade saw Mark and Daniel proudly sitting in Jeremy on the front of Less low loader as it wound its way around the streets.
Some weeks later disaster struck ! Over enthusiastic driving and carrying too many passengers resulted in the motor drastically overheating. Jeremy was left to cool down. Suddenly a plume of smoke appeared from under his bonnet and I rushed across to attempt to remove a battery strap only to be beaten by the cable, having melted the insulation, shorting and finally breaking the circuit.
Lesson learnt ; make sure that the circuits are properly fused ! Fuses are cheaper than motors !
Given time Jeremy will rise from the ashes this time harnessing a Sinclair C5 motor and hopefully with a folding windscreen to complete it.
It has been an interesting project which I hope will have
encouraged Mark and others of the merits of making something yourself and
understanding the principles of engineering, even if it is not right the first
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