Imperial or Metric?

[chilliMin]

Morning all
 

What are the best (i.e. easiest) units to use for a UK build?

With particular reference to concrete and steel fabrication?
 

[Crofter]

Metric all the way. 

Steel is sold in 6m lengths. 

Concrete by the cubic metre.

[MikeSharp01]

Metric. 

[SteamyTea]

SI

[saveasteading]

The only time I use imperial is in chat with someone aged over 45.

Then you might describe a timber in inches. Eg  6 x 2 

 

It's actually much more practical than describing it as 150 x 50, or 15 x 5.

Or 147 x 47   etc.

 

Or nails being 3 inches.

 

But it would still be a length in metres in ordering and in cutting.

 

It would be a very bad idea to design and work in imperial.

 

Steel beam dimensions  are actually usually still in the historic round numbers in inches but are now  always calculated and bought in mm.

[markc]

A guy I used to work with was ok in metric as long as they were whole numbers in 100mm increments - everything else was an imperial add-on.

3500mm - 3.5m

3600mm - 3.6m

3612mm - 3.6m and 1/2 inch

it made setting out conversations interesting to others.

[Crofter]

Just now, markc said:

A guy I used to work with was ok in metric as long as they were whole numbers in 100mm increments - everything else was an imperial add-on.

3500mm - 3.5m

3600mm - 3.6m

3612mm - 3.6m and 1/2 inch

it made setting out conversations interesting to others.

On a related note, I know a guy who insists that a 3-4-5 right angle triangle only works if it's in feet.

[JohnMo]

19 minutes ago, saveasteading said:

The only time I use imperial is in chat with someone aged over 45.

Why - I'm over 60 and was taught metric at school, it's been taught in school since about 1965! Only time since leaving I used imperial was working with equipment designed in 1940s.

And ordering wood in imperial cross section (which it isn't actually that size - 147mm is actually 5.79" not 6") and metric length - but building industry is backwards in its thinking anyway, so cannot expect much different really.

[Crofter]

4 minutes ago, JohnMo said:

Why - I'm over 60 and was taught metric at school, it's been taught in school since about 1965! Only time since leaving I used imperial was working with equipment designed in 1940s.

And ordering wood in imperial cross section (which it isn't actually that size - 147mm is actually 5.79" not 6") and metric length - but building industry is backwards in its thinking anyway, so cannot expect much different really.

I'm 44 and we didn't mention imperial units once at school.

 

For me, imperial is used for certain specific things e.g.:

- socket drives

- wheel diameters

- length of a boat

[Mr Punter]

The US and Canada like imperial.  Timber frame with studs at 2 ft centres, timber sheet material being 8' x 4'.  It can make it easy to set out.

 

I doubt many use imperial weights, other than for people eg 5 foot 8 and 18 stone = fat bastard etc.

[Crofter]

1 minute ago, Mr Punter said:

The US and Canada like imperial.  Timber frame with studs at 2 ft centres, timber sheet material being 8' x 4'.  It can make it easy to set out.

 

I doubt many use imperial weights, other than for people eg 5 foot 8 and 18 stone = fat bastard etc.

You can still buy sheet material in either metric or imperial in the UK. That was a surprise to me when I was designing my house. Except they call it 1220mm, not 4ft.

[-rick-]

1 hour ago, Crofter said:

I'm 44 and we didn't mention imperial units once at school.

 

For me, imperial is used for certain specific things e.g.:

- socket drives

- wheel diameters

- length of a boat

 

Similar here, though pretty sure imperial measures was touched on, though I couldn't convert metric/imperial in my head until much more recently. Whatever happened in school I think I've ended up using Imperial more as I got older* though not for anything important. I've always measured my height and weight in imperial but if I'm measuring or weighing anything else it will be in metric.

 

* In recent years I've been watching a lot of makers on Youtube and a lot of them are American and so I've been a lot more exposed to Imperial measurements than I was when I was younger.

[SteamyTea]

1" is 25.4mm exactly.

 

[JohnMo]

15 minutes ago, -rick- said:

I've always measured my height and weight in imperial

Strange until I joined the RAF (1986) I did the same, now its always metric so kg, and metres.

 

6 minutes ago, SteamyTea said:

1" is 25.4mm exactly.

 

Yes and 2.2 lb to the kg

[SteamyTea]

2 minutes ago, JohnMo said:

Yes and 2.2 lb to the kg

Not exact though.  I think the distance measurement is the only one that is a stated conversion rather than a defined one based on something real i.e. wavelength of light.

 

[JohnMo]

22 minutes ago, SteamyTea said:

Not exact though.  I think the distance measurement is the only one that is a stated conversion rather than a defined one based on something real i.e. wavelength of light.

 

Or more complete cut and paste is

Kilogram Definition: A kilogram (symbol: kg) is the base unit of mass in the International System of Units (SI). It is currently defined based on the fixed numerical value of the Planck constant, h, which is equal to 6.62607015 × 10-34 in the units of J·s, or kg·m2·s-1. The meter and the second are defined in terms of c, the speed of light, and cesium frequency, ΔνCs. Even though the definition of the kilogram was changed in 2019, the actual size of the unit remained the same. The changes were intended to improve the definitions of SI base units, not to actually change how the units are used throughout the world.

 

History/origin: The name kilogram was derived from the French "kilogramme," which in turn came from adding Greek terminology meaning "a thousand," before the Late Latin term "gramma" meaning "a small weight."

 

Unlike the other SI base units, the kilogram is the only SI base unit with an SI prefix. SI is a system based on the meter-kilogram-second system of units rather than a centimeter-gram-second system. This is at least in part due to the inconsistencies and lack of coherence that can arise through use of centimeter-gram-second systems, such as those between the systems of electrostatic and electromagnetic units.

 

The kilogram was originally defined as the mass of one liter of water at its freezing point in 1794, but was eventually re-defined, since measuring the mass of a volume of water was imprecise and cumbersome.

 

A new definition of the kilogram was introduced in 2019 based on Planck's constant and changes to the definition of the second. Prior to the current definition, the kilogram was defined as being equal to the mass of a physical prototype, a cylinder made of a platinum-iridium alloy, which was an imperfect measure. This is evidenced by the fact that the mass of the original prototype for the kilogram now weighs 50 micrograms less than other copies of the standard kilogram.

 

Current use: As a base unit of SI, the kilogram is used globally in nearly all fields and applications, with the exception of countries like the United States, where the kilogram is used in many areas, at least to some extent (such as science, industry, government, and the military) but typically not in everyday applications.

 

Pound

Definition: A pound (symbol: lb) is a unit of mass used in the imperial and US customary systems of measurement. The international avoirdupois pound (the common pound used today) is defined as exactly 0.45359237 kilograms. The avoirdupois pound is equivalent to 16 avoirdupois ounces.

 

History/origin: The pound descended from the Roman libra, and numerous different definitions of the pound were used throughout history prior to the international avoirdupois pound that is widely used today. The avoirdupois system is a system that was commonly used in the 13th century. It was updated to its current form in 1959. It is a system that was based on a physical standardized pound that used a prototype weight. This prototype weight could be divided into 16 ounces, a number that had three even divisors (8, 4, 2). This convenience could be the reason that the system was more popular than other systems of the time that used 10, 12, or 15 subdivisions.

 

Current use: The pound as a unit of weight is widely used in the United States, often for measuring body weight. Many versions of the pound existed in the past in the United Kingdom (UK), and although the UK largely uses the International System of Units, pounds are still used within certain contexts, such as labelling of packaged foods (by law the metric values must also be displayed). The UK also often uses both pounds and stones when describing body weight, where a stone is comprised of 14 pounds.

 

 

 

Kilogram to Pound Conversion Table

Kilogram [kg] Pound [lbs]

1 kg is equal to 2.2046226218 lbs

[chilliMin]

Thanks guys

I'm glad it's metric!

Interesting conversation too. When I measure my waist (fitness fanatic) I use cm/mm because the gradations are smaller (so more accurate) but covert back to inches in the spreadsheet.

 

[markc]

Inchworms are the larvae of geometer moths … 2.54cm worms doesn’t have the same ring to it.

[saveasteading]

Site survey completed. Concerning timber only.

The results are in.

 

The Architect and Engineer work in metric.

The workers talk in imperial as in "fetch me a 6 x 2 about 6 ft long.  But they measure in mm.

When talking designer to chippy, it is 6 x2 etc for ease of discussion, but lengths are in m. The younger designer never learnt imperial but has learnt to accept this parlance as "the way it is".

 

Builders' merchants accept an order for 6 x 2 but confirm and invoice  it in metric.

 

And on education. For my childrens' (1990s) education they were taught cm, not mm.

Real life has changed this and current teaching at primary includes both cm and mm but still no imperial.

[SteamyTea]

1 hour ago, markc said:

2.54cm worms doesn’t have the same ring to it.

Ringworm does though.

[SteamyTea]

If you need a good reason to use metric, and SI units specifically.