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Posts From October, 2010

Cardboard Box 

Labour Weekend, so my wife thought a good plan would be an expedition with some Danes to the top of Mount Arthur in the snow and promptly set off for the hut. Therefore I made a cardboard box and Mr McLeod, who isn't Danish, wasn't consulted and had organised a recumbent ride instead, made a tailfairing and Mr Schroder made a fork jig. To each of us our accomplishments: some climb mountains, some make tailfairings, some make fork jigs. And I make a cardboard box. - As a matter of fact I've been meaning to make the box for a while because the old one was getting worn out - it's on the back of the shopping trike and needed to be a whisker bigger because of the statutory size of New Zealand juice bottles, which prevent crisps and milk and grapes being bought at the same time. So I pinched a bike box from the shop because they're double-thickness corrugated cardboard, and set to with knife and PVA and little reinforcing sticks of willow and when it was all done, I carefully covered it inside and out with cut-up cotton shirts ostensibly to reinforce it but actually cos I fancied the idea and wanted to see if it would work.

 
Messrs McLeod and Schroder appeared and we went for a ride, Mr McLeod with his new tail fairing which was thin and flimsy and lightweight and insubstantial and rubbish all of which compelled me to assure him it wouldn't work, but in the event I was wrong. It worked exceedingly well. A roll-down at Ngatimoti said 38.8 kph without the fairing and 40.6 with, and whenever I followed him I found that I wasn't picking up a tow but was riding into immense turbulence which entirely validated his roll-down data. The tailbox was a single fold of corriboard, neatly sealed at the front with foam, and held in place with tiny light-weight rubberised cotton bands weighing nothing. Admittedly his drive chain was creating a series of hiccups, but nobody's interested in drive trains. They're only the means of testing the aerodynamics of single folds of corriboard. (And on the topic of hiccups the children who have decided I am to be knighted, presumably for services as yet unrendered, observed that the worst time to get hiccups is when the Queen is about to knight you. It is a prospect that doesn't fill me with alarm because I'm neither a rugby player nor a film producer and Her Majesty is not yet in the habit of knighting cardboard box makers.)


Mr Schroder had his fork jig with him which I shall probably have to nick sometime, and he tried to persuade me to ride from Rotoiti to Renwick with him but I declined because I'm pathetic and a wimp and it's a long way and he's too fast. Mr McLeod will have to go instead.
 
 
In the morning I nipped up Mount Arthur to see how they were all getting on and was much cheered to find that Dr Dane-Mollerup is another person who shaves his own head, doubtless to save having to discuss whatever in Denmark constitutes Leicester City with whoever in Denmark cuts hair. - By way of instigating stimulating conversation the barber in Barrow used to ask of each client:
'Y'suppor' Leicester City, er wha?'
Naturally I did not support Leicester City nor indeed any other team but I did not disclose this to the man because he had sharp implements and my throat to hand. Instead I bought a BaByliss and proceeded to shave my head with a Number 4, deeming that however ragged a mess I made in the mirror it would be preferable to a bimonthly discourse on association football. If you see a man with hair exactly half an inch long you'll know he has a BaByliss, and if there's a diagonal intrusive pathway mown out of the back of his neck only an eighth of an inch long, you'll know his wife declines to shave the last few bits for him with a Number 1.

Up the mountain was a Troll. He had appeared long after dark outside the hut, hopping about with a torch on his forehead and waking everyone up shuffling through his pack, and in the morning he set about advising people what not to do. Not to wear cotton shirts, not to wear cotton jeans, to choose different boots from the ones they had and to go on routes other than those they proposed. In short, to do what he was doing. Everyone ignored the Troll so he had to accompany them all day to give further advice, suddenly rushing ahead with his mountain sticks, randomly announcing which of the range is named Gordon's Pyramid and which Billy's Knob, and surprising people who hadn't ever seen him in their lives before by gratuitously pointing out the route to Salisbury Hut. He was most odd. He was covered in tattoos, very probably inflicted by mountaineers who had tired of his advice. I have a feeling he lives on the mountain, so when I next go up there I'm taking my cardboard box and I'm going to spend quality time advising him how to make one using inappropriate materials like cotton and we'll see who can be the most annoying and I bet it'll be me.





Penny trike 

Friday, October 22, 2010 9:33:04 AM Categories: Moving Bottom Bracket bikes penny farthing trikes
Meticulous care with the lathe - meticulous - and so I was only four thou out when I'd finished making the bearing housings. Four thou for heaven's sake! Again! Heigh ho, so what's new? I'm a rubbish machinist. But I own scissors, and Coke cans are to be had from the wayside. Neatly shimmed, the bearings sort of fit, after a fashion.

The frame angle is a Lowing Joint which is my favourite. The Lowing Joint is named after Dr Lowing who, in a series of complicated emails from the far side of the world, told me how to do this partic'lar weld which he calls a 'Double-D Joint'. When I finally understood I was so impressed that I renamed it, and the Lowing Joint it has now become in the great lexicon of recumbenteers, along with tadpole, which I rather disapprove of, and sitzhöhe, which I like.
 The rear axle got welded to a sleeve clamp so I can vary the wheelbase, and the vile handlebar got itself off that BMX which started the whole project off. No other handlebar would allow knee clearance, and I certainly wasn't about to waste time making one.

I had thought - being realistic - we would now have a completely ludicrous machine for riding round and round the house at a variety of speeds on varying numbers of wheels, destroying the lawn and various boy's (sic.) trousers. But the surprise was how much there was to learn from it.
 
The seat position puts all the body weight on the muscles doing the work and it's painfully uncomfortable but the seat needed to be well back to avoid putting the weight above a single wheel. Lifting oneself forward and up does make the thing dreadfully unstable because it isn't a bike. Ever ridden one of those Newton conversion trikes? Single back wheel from a conventional bike, but with two front wheels and Ackerman steering. I once rode one through the village along Warner Street, where there was a murder at number 12 and where Johnnie Johnson (1) was born at number 21. At the war memorial I got off and pushed it home. It was a Truly Horrible Machine. Effectively you're riding a bike because you're sat above the single of three wheels, and you're not allowed to balance because the second front wheel won't let you. Ghastly. I mentioned this to my brother-in-law who possesses a disabled child, and who is keen to get through money as fast as he can, and who was about to buy his daughter exactly this layout of trike for six hundred quid. I spoke of the shortcomings. He bought it anyway and whenever the child came to stay with us, she tipped herself off it into the road. (You paid for it, incidentally, not him. He applied for a government grant.)

When the wheelbase is long the trike isn't very stable, but is rideable. With a short wheelbase the weight is on the back wheels so the front wheel spins like a drag racer. But oddly enough, you don't immediately feel you need a wider range of gears. Your psyche seems to say, 'Ho, 26er, eh? I'm happy with that,' and you trundle along at double walking speed on the dirt roads of the orchard. But you soon realise the need both for a brake, and for footpegs for when you've wound it up to speed and don't want your knees to buzz like a Japanese motorcycle. And it has the remarkable sophistication of a reverse gear. And if you forget to tighten the clamps on the back axle it's a lean-steer trike. - Well, a lean-wobble trike.

Immediately, of course, thoughts of miniature penny farthings are provoked, either with a 29er front wheel which I can afford, or a 36er which I can't. 36er unicycles are to be had in New Zealand; I saw someone riding through the middle of no-where on one with a huge rucksack on his back. But Mr English, notified of the experiment, immediately discovered that 36er penny farthings are being made in Taiwan http://www.taiyingsystems.com/penny_farthing.php so now I fancy making a penny penny, which means a mountain bike wheel on the back too. Since this would be a FWD MTB fixie I imagine all the locals will get very enthusiastic about it. Or not. As the case may be.

1. Johnnie Johnson was Britain's highest scoring fighter ace of WWII. He shot down my wife's mother's fiancée. Probably.

Flanges 

Sunday, October 10, 2010 10:44:21 AM Categories: engineering problems penny farthing trikes wheel hubs
Right, attentive readers of these notes - I flatter myself - the attentive reader of these notes - assuming there is one, which is more than improbable - is aware that I am obsessed with the thought that quite soon all the oil will vanish and everyone will have to gather logs for their cooking balanced on their heads like the ladies in Darfur do. - The logs balance on the heads, not the cooking. - But anyway it seems to me every time I visit the dump I discover some cheery mortal has thrown away three quarters of a BMX and the remaining wheel has a 14mm axle. Ever picked up a BMX with a back wheel? Heavy. Ever tried to carry one home on your head? Cumbersome. Like logs in Darfur. And even carrying one on another bike's no good. So I need a better vehicle for dump recovery operations.
 
The BMX the cheery m. had thrown away had a wheel which, when coaxed apart, had had the wrong size ball bearings fitted, and when I replaced them with the right size, which ran on the unpitted part of the cone, I suddenly had a smooth bearing on a 14mm axle.
 
It is a fact that your brain immediately says 14mm = stub axles, if you chance to be a serial recumbent tricycle maker. You cannot help this. It's a reflex action.
 
I dived into the bookshelf and recovered my 2nd edition Bicycling Science and found the Oxtrike on p 325 and then on p 324 read that in Asia heavy loads of perhaps 330 lb, or 150kg, are carried on a single speed trike with a cruising speed of about 4-7 mph (2/3 m/sec.) Blimey! that's handy. - Any time you forget what 4-7 mph is, you can just back-calculate from knowing the velocity in metres per second. I do like David Gordon Wilson. Well of course everyone likes DGW. He designed the Avatar 2000. Which graced Richard's Bicycle Book. (Which actual bicycle - Mr Ballantine's, not Professor Wilson's - is now owned by Mr Wray, my spies inform me.)
 
So, quick calculation: cadence of 60 and a fixed gear of 26 inches gives a cruising speed of 4.64 mph. So that's 2.074707788 m/sec, Dave G.W., if you happen to be reading this. And if I want to go at 3.12928 m/sec, I can always pedal faster.
 
I was very pleased with myself and immediately decided to build a grown-up's child's tricycle. The pedals attach directly to the front wheel and obviate gears and chains and so forth, and all you need is the basic technology of the penny farthing.
 
Now I'll tell you about my flanges, and it's this - I got an old steel back hub and chopped it in half and bored the flanges to fit a cottered 5/8 axle and adjusted the cross-slide by one thou right at the end of the cut and for some reason unknown it jumped four thou and created a big floppy hole, like a thing that is floppy and not a thing that isn't floppy.
 
'******* ******,' I said to myself, 'but you're a *******; you've ****** it up again.' (I often say this to myself, because it doesn't matter what I'm doing, somehow I always manage to **** it up.)
 
So I got another lump of 5/8 from my tin of worn-out cotter-pin BB axles, and I ground the cones off carefully and made it a perfect fit on both my flanges. Then being warned in a dream that a 150 amp MIG isn't enough to penetrate 5/8 steel, I coated it with borax paste ready for brazing, and tack-welded both flanges in place and d'you know what - Juno Watt - both were square and parallel but the spoke holes weren't perfectly alternate.
 
'******* ****** but you're a ******* etc.,' I said to myself, and set about breaking the tack welds. And d'you know what, they wouldn't break. Had to saw them off. So I thought the MIG will actually weld it; I won't need to braze. So I sawed off the second flange's tack-welds and scrubbed all the borax off and replaced them and welded them up, and d'you know etc. etc. etc., now they aren't bloody well square. They *******  wobble. So I ******* went back to the box of old steel hubs and d'you ******* know what, I had absolutely none whatever that were suitable to machine 5/8 holes in. So now I'm ******* well stuck with wobbly flanges.
 
'Oh Damn and Blarst,' I said to myself, 'Better not show it to that ******* Knight or he'll know that *once again* I've accomplished a piece of ******* bad craftsmanship.'
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