0T: metric conversion

[The Medway Handyman]

See, I'm less confused now. Never confused....

[Rod]

From the B&Q website:

Product Features Width (mm): 38 Length (mm): 2400 Thickness (mm): 25 Length (cm): 240 Length (ft): 7.87 Length (inch): 94.49 Length (m): 2.4 Thickness (cm): 2.5 Thickness (inch): .98 Width (cm): 3.8 Width (ft): .12 Width (inch): 1.5 Width (m): .38 Product Type: Sawn Kiln Dried Timber

Five widths Five lengths Three thicknesses

Confusing? Or what?

[Corporal Jones]

Not really confused, in my apprenticeship I had to learn inches,Thous, mm, microns, Whitworth, BSF, BSC, Acme,UNF, UNC, BSP...... So that's why my brain hurts!!!

[geoff]

In message , George writes

Why don't you just type "convert 71.375 inches into mm" into google and ask it ?

[George]

18" is also easier to see than measuring 457mm...na then I'll have to measure that agin cos me eye's went a a bit dodgy then. ;-)

[Dave]

I am glad you posted that. It makes me feel better.

Dave

[Frank Erskine]

Just about the only people who seem to use centimetres are education-types and the BBC.

[Frank Erskine]

I have a tape measure marked on one side in feet and inches, and on the other side in hands :-)

[Dave Plowman (News)]

Also seems common with haberdashery for want of a better word.

[Derek Geldard]

Radio Amateurs ? Never heard one talking about the 700 mm band.

Radar bods.

Doctors describing cysts and tumour masses.

Derek

[Mike Barnes]

And furniture retailers.

There's nothing inherently wrong with cm as far as I can see.

[geoff]

They are just not correct sub units

The unit of length is the metre, this goes up and down in factors of thousands -so millimetres and kilometres are approved, centimetres and hundred metres are not

[Dave Plowman (News)]

Only if they don't specify it. If I give a metric measurement it will be in mm or metres - say 2.4, etc. And you don't normally say it is millimetres - if I said 255 x 450 most would assume mm - but as I said some assume cm.

[Rod]

I am not disagreeing with you - you are obviously reporting your experience of doctors using cm. In my relatively recent forays into such things, I have most often seen them use mm. (This is from international resources - the UK could be out of step with the world and I possibly would not have noticed.) And it is this inconsistency that really doesn't help.

I mean, the most common thing I see is some lump/growth on the thyroid being "less than 4mm". On the basis that the selfsame organ could easily develop a growth of 40mm, that does leave the door open to someone seeing the number '4' and just assuming it is tiny. We do often remember things visually and I think it likely that we are more likely to remember the number than the unit.

In a similar context, I keep seeing reports of people taking, say, 175 mcg of a particular hormone. Some write that. Others write 175 mg. Some others write 0.175 mg or .175 mg - or mcg. And, somehow, 0.2 looks to be

*less* than .175. At least with that mess it is possible to have a best guess interpretation. If they mixed in (sub)multiples of 10 at the unit level it would be really horrible.

But another related hormone pill is still sold in grains. (Actually, it has relatively recently changed to 30 mg as the 'metric equivalent'.) Together with halves and quarters.

[The Medway Handyman]

I would, depending on the context.

If cutting MDF to box in pipes, I would assume mm, but if building a deck I'd assume cm.

[Roger]

The message from Mike Barnes contains these words:

There is nothing inherently wrong with Imperial units either.

Cm are not preferred units in SI metric and belong in the dustbin of history along with dynes, ergs, calories and other obsolete units from the pre SI age.

Calories of course are in widespread use even by those who deprecate the use of obsolete units which tends to be a double whammy. 99.99% of those who actually use the term really mean kilocalories.

[Andy Hall]

Would you?

If mm were used, both are very obvious.

[The Medway Handyman]

But measurements like 1750 and 1705 are easily mixed up - by me anyway. 175 & 170.5 is clearer

[Mike Barnes]

Who does the approving, and more importantly, why should furniture retailers care about their "approval"?

[Mike Barnes]

So the SI doesn't "prefer" them? Why should that matter to a furniture salesman?

You forgot hectares, by the way. They're not going to die out anytime soon either.

I know. But that 99.99% uses calories for comparative purposes only so the absolute value is meaningless to them. Anyone who needs to relate calories to other units probably appreciates the distinction.