Thread: Stupid Imperial Measure Question

Originally Posted by artful bodger

There was an older patternmaker who worked next to me in a busy shop who had a rule that was in inches however the graduations between the inches were tenths,twentieths etc.
Came in handy when you got a drawing that specified tenths of inches. It did sometimes happen.

And in patternmaking, the scales are distorted to allow for cooling shrinkage of the casting. Different scales for different metals, too.

Cheers,
Joe

Originally Posted by ian

actually, I was down your way in August

Next time.

When I first started work, the gauge plates for river gauges were of two types. Where the gauges were manually read daily, they were in feet and inches. However, where there was a recorder, the gauges were feet and decimals of a foot. Some of these recorders had a chart that was changed weekly by local readers, some of whom had enough trouble dealing with feet and inches, let alone feet and decimals.
My (perhaps faulty) recollection is that when I was a surveying student 50 years ago, the nautical mile was defined as the distance subtended by one minute of arc on the surface of the earth at the equator. Since then, the standard geoid has been redefined at least twice, so that definition would no longer hold. Another consequence of these changes is where a grid reference from one system is used to try and find a position using a map or GPS based on another.

Originally Posted by AlexS

When I first started work, the gauge plates for river gauges were of two types. Where the gauges were manually read daily, they were in feet and inches. However, where there was a recorder, the gauges were feet and decimals of a foot. Some of these recorders had a chart that was changed weekly by local readers, some of whom had enough trouble dealing with feet and inches, let alone feet and decimals.

I remember those days.
Road plans drawn in decimal feet, a table of conversions (decimal feet to feet and inches) stuck on the wall beside the door, when the better answer was to give everyone a tape marked in decimal feet.

My (perhaps faulty) recollection is that when I was a surveying student 50 years ago, the nautical mile was defined as the distance subtended by one minute of arc on the surface of the earth at the equator. Since then, the standard geoid has been redefined at least twice, so that definition would no longer hold. Another consequence of these changes is where a grid reference from one system is used to try and find a position using a map or GPS based on another.

apparently it's even more fun now.
farmers plowing paddocks need to allow for either relativity, or the precession of the axis, or continental drift, or all three, if they want this years furrows to be in the same place as last year's. I don't fully understand why, but I understand that one land management practice is to try and plant this year's crop in the same narrow row as used last year.

And, the Systeme Internationale is changing. Delegates from 60 countries voted in favor to upgrade the reference standards for meter, kilogram and so on.
The chunks of platinum/iridium standards are changing sizes and mass!

Bakers still weigh the ingredients, it's the only way to scale a recipe up or down in size. I have software to do it.

In Canada, most older people seem to function OK in either system, as our grocery stores show imperials units for the metrically challenged
after what? 30+ years? I've worked in both most of my life but miles/kilometers is a tough switch to imagine.

When the road signs had to be converted, BC Highways Dept moved to signs to metric positions. K.I.S.S.

Originally Posted by Robson Valley

When the road signs had to be converted, BC Highways Dept moved to signs to metric positions. K.I.S.S.

an expensive exercise.
In NSW we made the change by riveting a cover plate with the km distance over the miles.
Most mile posts (triangular concrete posts) were left in place with new 5km distance markers being installed. On recent country drives I've noticed a relatively large number of concrete mile posts with cover plates -- which is interesting given that the switch was more than 40 years ago.