Imperial vs Metric

[Trainee neophyte]

From Wikipedia, so it must be true:

The metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately 40000 km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and slightly updated in 2019.

And then I got lost reading about yards...much more fun. I'm supposed to be cutting up bits of wood, but there is always tomorrow.

 

[Yojevol]

And what about model railway scales? they're all mm/ft eg:-

• Z Gauge. 1.5mm to 1ft, 1:200
• N Gauge. 2mm to 1ft, 1:148
• TT Gauge. 3mm to 1ft, 1:101.6
• HO Gauge. 3.5mm to 1ft, 1:87
• 00 Gauge. 4mm to 1ft, 1:76
• O Gauge. 7mm to 1ft, 1:48

How on earth did that come about?
Brian

 

[Droogs]

In 1999 NASA lost it's Mars Climate Orbiter because of a mix up in imperial and SI units between NASA and the contractors, Lockheed. Hey-Ho, only 125 million dollars cost!
https://en.wikipedia.org/wiki/Mars_Climate_OrbiterStick to one system.
Nigel

SWMBO has a cousin who works at NASA chemical physicist - proper rocket scientist. She worked on that one lol

 

[Dr Al]

From Wikipedia, so it must be true:

And then I got lost reading about yards...much more fun. I'm supposed to be cutting up bits of wood, but there is always tomorrow.

The 2019 definition didn't really change anything:

The new definition of the metre is effectively the same as the previous one, the only difference being that the additional rigour in the definition of the second propagated to the metre.

• Previous definition: The metre is the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second.
• 2019 definition: The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299792458 when expressed in the unit m⋅s−1, where the second is defined in terms of the caesium frequency ΔνCs.

 

[Just4Fun]

And what about model railway scales? they're all mm/ft

So what is the weirdest units anyone has worked with?
In my first job they were "going metric" and I had to convert a load of stuff from "gallons per cwt" to "000s litres per tonne". This was called the yield factor and concerned how much cheese was produced from quantities of milk. Yes, in my first job I was a human spreadsheet!

 

[Droogs]

@Just4Fun not a cheesemaker then just a clippy prototype


Just4fun's new avatar

 

[MikeG.]

Blessed are the cheesemakers........

 

[beech1948]

Similar to Musicman I was brought up in an Imperial only world. Imperial is better than metric for training ones brain to rapidly calculate the various Imperial measurements. BUT as the world has progressed I have had to force myself to convert to metric and over 15yrs in the 70s/80s I have replaced my machinery with metric equivalents where necessary.

I now run a metric only shop. I even refuse to think in terms of sheets of 8X4 ft but rather of 2400x1200 and try to buy hardwoods in metric only sizes. Oddly there are a few timber yards who have yet to fully convert.

Having done this I now rigidly use metric measurements on all timber. Sold my Imperial only tools.

 

[Droogs]

@beech1948, does that include chisels. I would have thought tat a 1/4" chisel would work as well in 18mm wood for a mortise

 

[MikeK]

I even refuse to think in terms of sheets of 8X4 ft but rather of 2400x1200 and try to buy hardwoods in metric only sizes.

Full sheets of plywood and MDF here are 2500x1250. Larger sheets are available, but that is the largest I can fit in the bed of my truck. Not including construction timber, hardwood is priced by the cubic meter. Last month, I bought a kiln dried slab of beech (3400x270x52mm or 0.048 cubic meters) at €1,190 per cubic meter.

 

[Phil Pascoe]

Blessed are the cheesemakers........

especially the ones at Cheeses of Nazareth?

 

[MikeG.]

........ hardwood is priced by the cubic meter.....

It is here, too, although the customer might not see it like that.

 

[Racers]

Extensively? Not in my part of the UK 160 years after that. I didn't come across a single thing in metric until the mid '60s, and that was at school because they were obliged to teach it.
Metres are fine. Millimetres are fine. Centimetres are the work of the devil, invented to confuse us.

Centimeters are used by infants who would be confused by big numbers, most of us grow out of that stage. So if you use centimeters you are still an infant.

Pete

 

[powertools]

For reasons I won't try to explain I work in both.
If anybody else does the same I can highly recommend Advent steel rules, it was another forum member who put me on to them, 1 face is inches only flip it over and the other face is metric only and as a bonus the Veritas ruler stop fits perfectly.
As an aside for thoes of you who work metric only the Advent Visa Versa tape measure is in my opinion the best you can get.

 

[lurker]

Ok, so I know exactly how long a mm or inch is and how to convert between them.
So tell me, exactly how long is a gnats?

 

[TFrench]

Daughter of a friend was being taught about centimetres at school, put her hand up and said "my dad's an engineer, he says centimetres aren't a real measurement"

I work in a hodgepodge of everything, despite being a metric child. I've only worked with old gits who don't talk metric, or get confused if you do. At work, pretty much everything comes in 1m lengths, but I generally cut it imperial because it only needs to be within 1/4" - its easier to understand in a deafening environment as well when you're calling measurements out to your mate. If it needs to be precise I work in mm, unfortunately the lathe and milling machine are imperial. DRO is definitely on the list for the lathe!

 

[MusicMan]

So what is the weirdest units anyone has worked with?

When I was a research student, we naturally shot the breeze in tea breaks. One friend was an Indian, working on a PhD in electron microscopy, measuring things in Angstroms (that's a tenth of a nanometre in new money) all day. Someone asked him "Das, how deep is the Ganges in your home town?". Without the slightest pause he replied "Oh not very deep, about two elephants".

Pretty practical unit really.

 

[Chisteve]

I worked with structural steelwork for 40 odd years and always used millimetres strange the majority of beam/channel section sizes are converted from inches so as example you end up with a 152 x 89 UB or 305 x 165 UB 46 beam and 229 x 76 PFC etc All weighs were in kg/tonnes

As others have said never used centimetres but do understand

Im 6 foot 11 and a half and I buy a 4 x 2 timber by the way

 

[MikeG.]

Everyone knows this is all just flim-flam. There are only four units of measurement that count: a gnat's nadger, a tennis court, Wales, and a double decker bus.

 

[MikeG.]

.........Im 6 foot 11 and a half.......

You missed your calling in life. You'd have made an absolute fortune as a plasterer.