imperial

Another beautiful day: 20+C, sunny and a light breeze. The children spent the day outside playing with friends and generally acting (literally) like monkeys while I also played with them, caught up on blip (check out the last three weeks; first one here!) and tinkered with more bikes.

This time the bike was my road bike; sadly neglected over the last year it's still in good form but had an odd click coming from the bottom bracket/cranks under load so time for a quick strip down and rebuild. Fortunately it's one of the newer style cranksets with an integrated spindle and outboard bearings so very easy to strip down. Make sure everything is thoroughly cleaned and it's a go. Splined spindle, self-extracting bolts, all very well thought out.

Of course, I couldn't find the cup spanner so had to go raking to the bottom of the tool box and unearthed this item. My father trained as a mechanical engineer and we spent many many wet weekends in the garage fixing things, working on bikes or doing model engineering - which leads directly to esoteric imperial bolt/thread systems.

1/2 W 9/16 BSF == 1/2" Whitworth, 9/16" British Standard Fine. One refers to the bolt diameter, the other the nut outer face distance (of course). Whitworth is well worth reading about...