[RedDevil]

Originally Posted by Xist

Curious. I am not sure when I last had enough sleep, but I usually use more precision than 2.54 cm per inch, although it took me a while to find anything more precise than that. Then I found 2.5400051 cm.

2.54 cm is adequate for me. 1 / 0.03937 = 25.400051.

Converting different English units is a pain, but from Imperial to Metric can cause your orbiter to crash.

Anyway, I need to figure out how to replace the alternator tensioner bolt on my Accord. Parts stores do not carry it. Either I drive seven hours for $15 or less in parts or I wait a week for shipping.

In theory I could fix my Civic sooner.

I would not bet money on it, though.

Actually, the inch is 2.54 cm exactly by definition: https://en.wikipedia.org/wiki/Inch

In 1946, the Commonwealth Science Congress recommended a yard of exactly 0.9144 metres for adoption throughout the British Commonwealth. This was adopted by Canada in 1951,[25][26] the United States on 1 July 1959,[27][28][29] Australia in 1961,[30] effective 1 January 1964,[31] and the United Kingdom in 1963,[32] effective on 1 January 1964.[33] The new standards gave an inch of exactly 25.4 mm, 1.7 millionths of an inch longer than the old imperial inch and 2 millionths of an inch shorter than the old US inch.[34]

As luck would have it, 2.54 was right in between the Imperial and the US inch.
Since then the inch officially is 0.00000000254 times the distance from the poles to the equator.

But it goes too far to call the inch a metric unit.
ISO_2848 defines a metric foot (30 cm) and inch (25 mm).
Which nobody really needs, of course.