Friday, July 16, 2010

A 19/32" Bicycle Cone Spanner (Wrench)

I'm restoring an elderly, long neglected Raleigh Grand Prix 10-speed road bike to road worthiness. It's proving to be an interesting project, not least for some of the arcane tooling and methods that one must come up with to deal with some aspects. Bicycle mechanics is a world apart from all other mechanical work that I'm familiar with. A masterful bike mechanic is a real mechanic who understands the nature and the interrelationships of a bike's components, and can make them work harmoniously; he's not just a parts swapper.

One of the arcane bits of tooling requirement that I came across was for a 19/32" spanner for the cones and jam nuts on the wheel axles. Good luck finding one of those.

But 15mm spanners are readily available, and 15mm is just shy of 19/32"; like so:

19/32" = 15.08mm (i.e. 15mm + 0.08mm = 19/32").

What that tells us is that you only need to widen the jaws of a 15mm spanner by 8/100ths of a millimetre and you have a 19/32" spanner.

I have a 15mm spanner on hand, but it's a top quality one that I didn't want to mess with. The local bike shop had a two-piece set of medium quality cone spanners for $9.95 -- a 15mm and a 16mm. I didn't already have a 16mm, so I bought the set to get me a 15mm spanner that I wouldn't mind modifying, and a 16mm to add to my collection of useful standard tools to have on hand.

The spanner is made of pretty hard tool steel, but it's not file-hard. A few firm passes with a suitable mill file were all it took to get the spanner's jaws opened up a bit, and voila, a 19/32" cone spanner:

'Spanner' vs. 'Wrench'

This is one of English's little quirks that has long puzzled me.

The words are interchangeable, really. The Brits seem to use the word 'spanner' for a wrench of any kind. In Canada and the USA, we use the word 'wrench' for most anything that one would think of as a more-or-less ordinary sort of wrench, reserving the word 'spanner' for specialized forms of wrench, such as these thin ones for bicycle axle cones and jam nuts.

In any event, I now have a 19/32" spanner/wrench/implement-for-dealing-with-Raleigh-cones/whatever.

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