Thread: Stupid Imperial Measure Question

Hi,
Is our membership measured in Short Planks?

Regards

Originally Posted by Bushmiller

........ I was completely unfamiliar with that being somebody who always has had difficulty getting his head around board feet. It does seem to me that much is dictated by local conditions. While you may well get a board a foot wide in Oregon (ahem, I mean Douglas Fir) it is more difficult to find something that wide in an Australian hardwood for example and if you did, by the time it had shrunk down from it's nominal width of 1" it would have severely cupped too........

Paul, a super-foot or a board-foot is a volume measurement. When the wood is cut to Imperial dimensions, it doesn't matter how wide or thick it is, it's actually quite easy to calculate how many super feet you have. If it's 6 inches wide and 1 inch thick, every lineal foot is half a super foot. Because 12 is divisible by so many integers, it's just as easy to calculate when the board is 9, 8, 4, 3, 2 or 1 inches wide, and 1,2 3 or more thick. It was a very useful measure, back in the day, because wood was priced by the super-foot & I'm surprised you weren't exposed to it in your milling days, but I guess you arrived on the scene after it had been buried by the metric system. Wood is still priced by volume (per cubic metre) but that's a big pile of wood, & it's a whole lot less easy for my brain to convert a cubic metre into x number of chests of drawers or tables!

As for cupping, shrinkage, splitting & surface-checking, well, I seem to recall that happened much the same with wood cut to either Imperial or metric units....

Cheers,

Originally Posted by IanW

Or, just 4 super feet (or board feet, depending which side of the Pacific you live on)...

no, no, not at all

12” x 12” x 4” is a very thick short plank

Woodturning blank.

Originally Posted by A Duke

Hi,
Is our membership measured in Short Planks?

Regards

How thick is that?

Then there is the good old standard measurement only found outside of major Australian cities, the country mile, ask any farmer, he will tell you how far it is, then there's the city slickers method of determining time "be with you in a sec".....10 minutes later or the the transport industry standard "next day delivery" they don't nominate the day (Sunday, Monday, etc)

What a coincidence the definition for a bunch of metric units have just been redefined

https://www.nytimes.com/2018/11/16/s...asurement.html

Originally Posted by ian

Nautical miles persist for navigation in part because 1 degree is approximately equal to 60 Nautical miles, with 1 minute of arc equal to 1 nautical mile.....

Not quite true, Ian.

A nautical mile is precisely one minute of longitude anywhere, and approximately one minute of latitude at the equator. In navigation, you therefore always scale from longitude.

Even the metric countries navigate in nautical miles and measure wind and boat speed in knots - a nautical mile per hour.

A few hundred years ago it was thought that the world was a little smaller and that a nautical mile was 6,000 feet or 1,000 fathoms long. Thus a fathom was a metric of a nautical mile. When the error was discovered the length of a nautical mile was left at one minute of longitude, but "adjusted" to 6,076 feet; a fathom is still 6 feet and there are now 1,012.667 fathoms to the nautical mile, a rather awkward relationship.

If the opportunity had been taken to simultaneously adjust the length of the fathom so that it remained at one thousanth of a nautical mile or minute of longitude then we would have a metric unit in navigatin. And iiif a metre had been defined at 1 fathom long then the navigation and other measurement systems would coincide......

Lots of ifs!


Cheers

Graeme

Originally Posted by Blocklayer

Dozen is another weird one. Funny how Australian chooks never went Metric with the rest of us in the 60's, and still lay eggs 12 to a box.
......

How true.

But I have just returned from a visit to Japan and China. The Japanese do not have a word for dozen and their chooks considerately lay eggs in batches of 5 and 10.

But the Chinese do have a word for dozen (dǎ in standard Chinese) and their chooks obligingly do lay eggs in batches of 12!


Cheers

Graeme

Originally Posted by GraemeCook

Not quite true, Ian.

A nautical mile is precisely one minute of longitude latitude anywhere, and approximately one minute of latitude longitude at the equator. In navigation, you therefore always scale from longitude latitude.

Even the metric countries navigate in nautical miles and measure wind and boat speed in knots - a nautical mile per hour.

A few hundred years ago it was thought that the world was a little smaller and that a nautical mile was 6,000 feet or 1,000 fathoms long. Thus a fathom was a metric of a nautical mile. When the error was discovered the length of a nautical mile was left at one minute of longitude, but "adjusted" to 6,076 feet; a fathom is still 6 feet and there are now 1,012.667 fathoms to the nautical mile, a rather awkward relationship.

If the opportunity had been taken to simultaneously adjust the length of the fathom so that it remained at one thousanth of a nautical mile or minute of longitude then we would have a metric unit in navigatin. And iiif a metre had been defined at 1 fathom long then the navigation and other measurement systems would coincide......

Thank you Graeme, we really should try and meet up over a coffee or beer some day.
When I said "approximately" I was being a bit pedantic and allowing for the fact that the earth is not a sphere, but an oblate spheroid (AlexS will know what we are talking about so the distance equivalent to 1 degree of latitude varies depending on where you are on the spheroid -- 6110 feet (1861 m) at the poles and 6050 feet (1843 m) at the equator. The international definition os 1852 m. Perhaps BobL will come along and convert that to the equivalent number of wavelengths of a Helium-Neon laser

https://youtu.be/txPcLOtbG3s

That's gold

Bit like ordering a hamburger but all you get is beef unless you order a bacon and egg roll then you get your ham

Originally Posted by ian

Thank you Graeme, we really should try and meet up over a coffee or beer some day. .....

Hi Ian

Too much white stuff north of the 45th parallel for me; but I'll put the coffee machine on for when you head this way.


Cheers

Graeme

actually, I was down your way in August