Saturday, March 17, 2012


Oh pig, John's high racer needs bushes and bushes are very easy to make on a lathe but I am stupid and incompetent to a degree unparalleled even by an apprentice from Wisbech when it comes to a simple item like a bush and a complicated machine like a lathe.

I made bushes. I made them out of nylon. I inserted them in the swing arm pivot housing. I reamed them with my home-made reamer, which is a 12mm tube with an angled end, the edges filed smooth and then stoned razor sharp. I fitted the inner pivot tube and one of the little bastards bloody well rotated in the outer pivot housing, which has its ERW ridge inside left intact to prevent exactly this from happening. I was MAD.

I took it out and fitted a shim and put it back and did all the swearing that accompanies fitting a shim, and it still bloody well rotated in the outer housing so I was STILL mad.

I haven't got much machineable nylon left. It all came from World Hero Mr. Sleath, who used to live near me in Leicestershire and who used to build recumbent trikes and recumbent bikes and model boats and who kept a small wind tunnel in his garage and three lathes and a milling machine he made while he was a student and some inexplicable stone otters that he had trouble moving, when he moved, which he did no doubt as a pre-emptive measure to stop himself feeling lonely as soon as he found out I was about to emigrate. Anyway one day at a race in - what’s that place called - sort of not-quite-figure-of-eight-track not quite near Ashby de la Zouch - Curborough, knew I'd remember - he came up and dumped a bag in the boot of my car and when I got home I found it full of acetal off-cuts, and since acetal is as expensive as bronze I was one of the happier people who hadn't won any of the races, which I never did, except for only once when I sort of cheated. (Got in a train with Nick Martin, who had to brake at the finish line so's we'd come in equal first. You don't get that sort of sportsmanship in the UCI.)

A drill press, this morning. 2 reamers, 2 munted bushes, 1 hole cutter, 1 donor acetal offcut, 1 usual benchtop mess

So, out with the pre-munted nylon wheel and using a hole cutter in the drill press, and at slow speed so's not to melt the nylon, and lots of short cuts ditto, I hole-cutted (p.t. of to hole-cut. Like hacksawed, not hacksawn.) into being a 19mm rod of nylon with a ¼ inch hole down the middle of it and popped it the 3-jaw and proceeded to machine one end exactly a millimetre too small for the outer housing because I am really, really stupid and truly incompetent and unbelievably impatient and grossly careless and sometimes I hate m'self and I don't know why Mr. Knight of the village of Near Christchurch or Mr. English of the village of Near Canada continue to talk to me. Mr. English has just won a whole lot of accolades in America. His engineering is a bit better than mine and his bikes don't weigh quite as much. - He wishes to know, in passing, why there isn't a country called Canadia:

I just got back from the big (ie biggest) handbuilt bike show (the name does seem a misnomer; I assume they conveniently forget that all the Chinese, Taiwanese and Indians use their hands to build bikes too (Chinese are from China, why aren't Indianese from India? Something like the Canadians from Canadia. Or something) - Rob

So then - back to my bad machining again (we leave, with reluctance, Mr. English's geographical musings) - I said quite a lot of the words, quite a lot of times, that one does say on such occasions.

And I turned the rod around and machined the other end so it would be a really, really tight fit in the outer housing, and drilled - with a drill - a 12mm hole through it, and parted it off, and hammered it into the outer housing and when it had just entered I squeezed it into place with the vice and behold! it went in properly. Leaving too tight a 12mm hole, of course.

But luckily Scott at Rural Supplies had managed to get me a 12mm reamer. An or'nery reamer was $98, and an adjustable reamer was $28, so I'd ordered the adjustable one and was surprised, opening the grease-packed bag, to find it was made of blackened mild steel and was stamped India. So you get what you pay for.

Mind, my brother, who's a proper engineer like Mr. Sleath and Mr. English, tells me he buys

pretty decent machine tool parts from RDG in England.

And if RDG, whoever they might be, would care so send me one for nothing by way of gratitude at this free advertisement I shall be most pleased, but I expect they won't, because as far as I can detect the only people who read this blog are Room 3 St Joe's School, and I can't imagine too many of them will be in the market for machine tools.

But as things turned out it was perfect for reaming nylon because I could adjust it to take a succession of light cuts and end up with a good smooth firm fit, and so it proved and I was happy in the end, which isn't always the case when I've been in the workshop. Didn't even cut m'self this time.



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