[sdiy] Metric OT rant

jorgen.bergfors at idg.se jorgen.bergfors at idg.se
Tue Aug 13 15:11:29 CEST 2002

>You do learn interesting things when you least expect it. Many thanks

>Where did you find that info? (I could not find it at C. E. Johansson's

I think I got it from an old friend, who is extremely knowledgeable in all
things mechanical. We were repairing steam locomitives together, years ago.
That's where I learned most of my metalworking skills, at least those for
working with larger items.
On the (old) steam engines metric fasterners were seldom used. The main
problem was to figure out if the nut or bolt was Witworth or UNC.
By the way, before we had the metric systen in Sweden, a swedish inch was
24,75 millimeter. There were frequent problems because swedish and british
inches got intermixed.
An interesting example was when a certain railway was built. They ordered
the locomotives in England, using eglish feet for the track gauge. The
english company thought it was swedish feet, so they converted to english
The company which got the order for the rolling stock correctly interpreted
the track gauge as english feet. But the tracklayers thought it was swedish
feet. So when everything was delivered, they had one width for the track,
another for the locomotives and a third for the cars. It turned out the
locos were the most difficult to change, so they changed the wheelsets of
the cars and relaid the entire railway line. That's why this line had the
uniqe track gauge of 1093 millimeters.


P.S. for a while (1863 - 1888 I think) Sweden even had decimal inches,
which means 1 inch = 1/10 foot (and that was a swedish foot). It of course
resulted in even more confusion, so then they gave up and adopted the
metric system.

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