11 August 2019

Making a steering wheel.

The Morgan 4/4 already had a wood steering wheel the Mota Lita but it is really substantially aluminium alloy with only the rim made of wood and that is plywood with little intrinsic strength, having laminations that are radial and so adding no rigidity.
A recent wandering through a classic car show sparked the idea, seeing a 1914 Hupmobile with its wooden spoked wheels and a crude wooden steering wheel that has stood the test of time.
Having already made a few wheels for toys for my young grandchildren I knew it could be done for the Morgan and set about the job with a wooden mould onto which the timber would be built up in laminations approximately 1/16th in thick. Cascamite resin glue was used for the outer rim and its a sticky job requiring glove protection for my hands.
Firstly the laminations are cut and planed to size and steam softened over boiling water in a pan. Allowed to cool and held to the mould with crocodile clamps. The tricky bit is ensuring full contact between the layers. There are probably better methods than mine such as vacuum bagging or wrapping with string to exert sufficient pressure. But this was to be a prototype and seems to have succeeded but admittedly, could be bettered.

Spokes most of which were rejects. Note the sharpened one drove through the redwood plank.

Hub and rim moulds

The outer rim is easier to fabricate than the inner hub because the clamping has more space to fix the clips. For the hub I resorted to laminating the outer layer free of the mould; after setting, the inner laminations were inserted and clamped from the inside as they naturally expanded to meet the surface of the outer layer. The ends of all the layers were feathered at both ends and tapered so that there were no but-ends or gaps. Once completed the two rings were lined up and marked out for drilling. Holes go into the outer rim from the inside approximately ⅓ in deep so as not to penetrate through to the outside. The inner hub was drilled to the full depth so that the spokes could be inserted from the centre of the circle and out through to the rim.
Spokes were cut from mature bamboo and approximately 3/32 in diameter. Each one drove through a suitably drilled hole in a piece of steel bar to ensure they were of a similar size.
Finally, the whole thing was sanded smooth and a coat of linseed oil applied. If you are not sure of the strength of bamboo to make spokes I can confirm that it is more than adequate, having driven a sharpened test spoke through a 1 ¼” plank without any harm to the wooden “nail”. 

With the steering wheel now in place, I am delighted with the result and tested with a drive out to Bristol. Further drives around Devonshire including Dartmoor and the narrow lanes have confirmed the wheel to be a success. Lighter in weight and more sensitive to the way a Morgan gives back road surface feeling. 

Also fabricated is a new gear stick knob to match the wooden dash, replacing the alloy one that was cold to the touch.

For previous attempts at wheel building, see earlier post: Balance Bike

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