Friday, June 5, 2009

Wheel discs

In between discussing how best to transport his stone otter collection on moving house, Clive Sleath once told me that he used foam for wheel discs. We will not enter into a discussion of Clive Sleath's sanity - this is the Internet, after all, where innocent children roam - but it always struck me that foam would be an excellent wheel disc and so it proved until I left a bike leaning against a pleasant wayside oak in the sun and the air inside all the little closed cells expanded and the foam became all mountainous and started rubbing against various frame parts and whatnot.

Corriboard is the stuff for wheel discs: like foam it is free: all you need is some pre-loved estate agents' signs. - The signs are pre-loved, not the estate agents. We will not enter into a discussion of estate agents etc etc etc though they don't collect stone otters as far as I'm aware, nor three-foot model hydroplanes a small steam traction engine a home-made milling machine a very small wind-tunnel and three lathes. (Quite an interesting place, was Clive Sleath's garage.) 3mm thick corriboard is good for 406 wheels, though you might manage 4mm thick for the flat side of a dished 700c rear wheel and not need to cut out a slice of cake. (This may become clearer later, depending on how eloquent I'm feeling this morning.)

My pre-loved estate agents' signs have bullet holes in them. These are real bullet holes and not those foolish stick-on things that adorn Saunders' wife's car (whatever for? Conversation starter? 'I see you have cheap imitation bullet-hole stickers amusingly placed on your car. Why, pray? Do tell') and I know they're real because I stole them off the rifle range, where some keen-eyed lad had arrived to sight in his rifle and then discovered he had nothing to shoot at. Apparently this is very common. Ross Fitzsimmons, who is a keen rifleman, once told me that 'you're not a real hunter until you get to the hut and find you've forgotten the bolt of your rifle.' (Apologies to all English people reading this, since I'm aware that everyone in England now eschews such things as rifles. Which fact pleases me inordinately because they're all out there busily buying A Certain Book to read up on catapults, bless them.) - Along comes a hunter in his Ute and unloads all his shooting gear. Hunters all have Utes. Wild animals are going to be perfectly safe when the oil crisis comes, because hunters cannot function without a Ute. - It is an Australian word, and means Large Bulbous Ugly Japanese Pick-up Truck. - Anyway then he finds he hasn't got a target, so back down the road, shortly to reappear with an estate agent's sign. He expresses his love for this sign with his rifle, and then drives off again leaving the sign several Coke cans and a fag packet, and all his empty cartridges which I pick up and carry off home so that John can indulge in Trench Art. You can still buy solder in New Zealand.

Early Learning Centre Buyers have thus far not made John any approaches. In passing, his violin teacher is puzzlingly optimistic if she imagines he is going to practice that atonal A Thomas piece she gave him last week. It's horrible. Really, truly horrible. I have this theory about why A Thomas isn't as famous as Bach, but we won't go into it right now.

Okay: what you need is Apparatus, and the special thing for wheeldisc making is a stick with a nail in it. More elegant tools have been made, some by chimpanzees, but a stick with a nail is all you need for corriboard. For a 406 wheel, drill another hole 198.5mm from the nail and into it screw one of those square-headed screws that are all the rage with builders. File the tip of this screw so that it's as sharp as a scalpel. Whack the nail right through the stick, and screw the scalpel far enough to protrude 2mm. Spread the estate agent sign on the carpet, bonk the nail through it where you propose the middle of the disc will be, and if the scalpel-screw is sharp enough, it cuts a perfect circle in one quick sweep. Try cutting it with scissors and it'll take half an hour and still be a bit wonky.

I always try cutting the middle hole in the same way - same diameter as the centre of the hub, natch - but it never works and I always resort to a Dremel. Next, pair of scissors, and cut a radius across the diagonal of the corriboard grain. This theoretically prevents buckling. Then cut out a 'slice of cake' to turn the thing into a cone. You cut another radius about 3/4 of an inch away - I did measure this, and cunningly wrote it on a bit of paper but I mislaid it because I am incompetent, but it was either 18 or 23 mm (can't remember which) at the circumference - and tug the two edges together to make your cone. Fix with duck tape. Do not spell this duct tape, which is wrong. You don't get duct cotton. (I state this to annoy all who hold the contrary view.)

Now apply to the wheel, and using a Phillips screwdriver whack in nine equidistant holes about an inch in from the circumference, and use 6mm nylon nuts and bolts to hold it to the identical wheel disc on t'other side. And then all you need to finish the job is to apply a bandage to your hand where you impaled it making the matching holes. A minor irritant is having to undo all the nylon bolts looking for the valve. Cleverly made holes and flaps always fail and eventually make click-click-click noises. Another minor irritant is trying to cut out a hole in the corriboard to get your wheel magnet close enough to the sensor for the computer to work. Another minor irritant is that it does, actually, slightly swell in the sun. Another minor irritant is that I keep increasing the number of minor irritants, wherefore I shall now stop.


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