Sunday, May 20, 2012

Tube bender

This week it went through my mind that Mr. Knight would like me to build a wooden three quarter inch tube bender more than he would like me to make a hardened steel one like his, and given the fact that that this surmise was either correct or incorrect, I have to admire myself for nearly getting the Right Answer. He nearly wanted me to build one. I betook myself to the lathe anyway, and for a happy hour sprayed myself and the inside of my overalls and the inside of my welly boots and the inside of my hair eyes socks and unmentionables with applewood shavings, and ended up with a variety of rollers with approximate three-quarter inch grooves in them. How does an applewood shaving penetrate overall, trouser, thermal, welly and end up on the inside of a sock? Why they bothered with the Large Hadron Collider when there are greater mysteries to be solved I do not know. I wore a hat and ear defenders and goggles and a face mask and the shavings penetrated all of them.



When I had rollers I made some bearing holes in some planks (applewood of course) and a handle (applew.) and using quite a lot of hands and knees and teeth managed to wriggle some clamps in place to hold a three-quarter inch tube firmly in place and then I applied a bending force. Luckily I had envisaged that a tube bender would be useful to make seat tubes.



Unluckily it was rubbish. It was as useless as a useless thing invented in the useless department of a useless laboratory by a rubbish inventor and made by a rubbish technician whose strength calculations were absolutely rubbish and it didn't work at all. It was weedy. It was pathetic. It was like a flimsy thing made out of three pounds of applewood and not like a stout unyielding thing made out of half a ton of cast iron. I jumped about on the end of the lever and had no effect whatever. When I looked at the tube it was still straight and although I narrowed my eyes and pursed my lips it merely smirked at me.

One of the rollers had got itself sawn in half and half remained untouched. In a prior retail expedition to the junk shop I had found one of those Odd Things that you don't understand but know you'll never see again so I'd bought it in case it turned out to be a Useful Thing and it sat about on a bench until Mr. Johnson pointed out that it was a pipe clamp. Mr. Johnson is a Member of the Diaspora who came to live in New Zealand forty years ago, and is related to Dr. Johnson who wrote the first dictionary so when he tells me something's a pipe clamp I incline to believe him. He owns a Myford lathe that was personally given to his father by Edgar T. Westbury. Edgar T. Westbury was a Director of Myfords, which fact was not advertised in any of the vast multitude of his Model Engineer magazine articles. There's nothing new about Product Placement.

Combining half-roller with pipe clamp was the work of a moment, and behold! there was an alternative tube bender.



Well it works, sort of, except with a lot more crinkles than nudging a bit of tube along in a vice, though it does have the mild advantage of allowing you to see how long your bent tube will be before you bend it, which I found difficult juggling tube and roller and vice and steel ruler.



The encouraging thing is that three-quarter steel tube is amazingly hard to bend. This means that when welded into a seat frame it will remain hard to bend, and the webbing will stay tight. Which is what everyone has already found empirically, so it isn't really news.

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