Woodworking measuring units

[Niki]

Good day

When I'm planning the dimensions of a project, I normally write the measurements in Centimeters, like 54.0 or 85.3, because that's what I read on the measuring tape or the ruler (and also for my wife to understand it).
But I noticed that the woodworking measurements are in Millimeters.
A length of 153.6 cm is very easy to see on the measuring tape while 1536 mm is forcing me to thing for a second what or how I have to read it on the measuring tape or ruler, of course, I just have to put the dot (in my mind) before the 6, but then, why not to put it there at the first place.

I worked in aviation for 36 years and I remember that we had to change many placards of switches, selectors and lights to reflect exactly what they mean, for example, an Anti-icing switch was placarded as "Open" or "Close" and not like before "ON" or "Off".

I think, that if you will tell your client that the unit will be 3565 mm long and 2005mm high, he will tilt his head (to consentrate all the IQ in one place) with a question mark on his face.

So what is the reason for the measurements to be in mm if the ruler reads in cm.

Regards
niki

 

[engineer one]

not sure if this is the only reason niki, but it is to do with the way we
are taught metric in the uk. remember it is only 30 years since every
body was working in feet and inches, and our wonderful fractions of
1/64, 3/32 etc.

i seem to think that somewhere i read that a decision was made in
government to teach millimetres not centimetres, but having been
wrong before could be on this one too.

i note that many polish builders/chippies over here do work in
centimetres, so there is a communication problem, and you are right
however in view of our education system right now, i
wonder how much trying to teach centimetres and millimetres might
well be even more difficult.

anyway, i have to tilt my head back to move the sawdust before i
scratch :lol:

paul :wink:

 

[Scrit]

Measuring tapes on machinery tend to be in mm - even on German machinery.

I vote we go for inches and Bobs, or then again, maybe not :wink:

Scrit

 

[wrightclan]

Measuring tapes on machinery tend to be in mm - even on German machinery.

I vote we go for inches and Bobs, or then again, maybe not :wink:

Scrit

:lol: :lol: =D> =D>

Brad

 

[David C]

Bobs have a lot to be said for them! But I doubt they will catch on in industry.

I regret to say that I think thousandth's of an inch for very small things, metric up to about 35 mm and then revert to imperial for larger stuff.

Life is much too short to work out what 21/64ths" looks like though I was good at this when under ten years old.

Perverse or what........

David Charlesworth

 

[Anonymous]

I think its because centimetres don't technically exist. SI units are the mm and then the metre. The cm is a made up unit not an SI unit.

Its what you get used to, I now think totally in mm's and just can't fathom some of the older boys I know talking in 37/64th's, even clients who talk in cm's seems odd.

 

[wrightclan]

...The cm is a made up unit ....

All units are made up units... :-k

Brad

 

[BrianD]

As a metric man, converted to metric when I was approx. 11 yrs old) I am used to mm and not CM and dfinitely not Imperial.

In engineering this is common practice and the convention avoids misunderstandings. And you can measure large items such as 1km = 1000 000 mm. So it is very versitile in that sense.

Although the UK did commit to the Metric system, a long time ago, the government did not do enough to encourage it. UK could have lead Europe in having metricated products with the result having plywood/MDF of 20mm and not the hybrid of 17/18/19 mm since one now is dependent on the supplier having Metric/hybrid/Imperial/other equipment. I must say I find this quite frustrating.

A missed opportunity methinks!

 

[Scrit]

As an interesting aside when I lived in the Netherlands in the late 70s there was a "measurement" of a "duim" (pronounced dow-m) or inch (25mm) still in use. The same country also had the "onz" (ounce) which was actually 100 gms (or 1/4 lb, 4 oz).....

Scrit

 

[dedee]

Slightly OT but I always think of "cold" in celsius but "hot" in fahrenheit.

Andy

 

[nickson71]

I think I'm a bit on the strange side


If I'm making something for someone else I work in what ever units they give me ....... (in the case of my boss it's inches)

Also if I'm designing or making something my self I use both mm and cm sometimes meters too

it all depends on the length if less than 1m I tend to measure in mm
if between 1-2m I measure in cm

anthing over I use meters

The realy strange thing about the first is I've never been taught imperial ..... metric all the way

 

[Roger]

I've just got bits of everything, due no doubt to spending varying amounts of time in odd places :shock:

With Cabinet work I think in Imperial feet and inches, but tend to combine everything when making a piece, depending on the purpose! I just can't get back into Fahrenheit somehow and can only relate to temperature in Centigrade.

I do like the Bob though. That would be great for workshop use

 

[WellsWood]

The thing I don't get is the inconsistencies. We teach the metric system exclusively in our schools ( as far as I am aware), we buy food in Kgs and Litres - God help the local butcher who tries to sell you a "pound" of sausages, we run our athletics races in 100/400/1000 Metres etc., we buy petrol in Litres and then get in the car and drive at 30milesper hour on tyres which are (in my case) 185mm wide with a 15" diameter :?

Mark

 

[engineer one]

it's a bummer ain't it?

the metrics we blame on napoleon.

the combination we have to blame on the americans and the
japanese who make the most cars. i mean it is only because
of henry ford that cars in america drive on the right.
before him, and the model t they drove on the left.
well actually there were no rules, so he re-wrote them
and the world has being paying the price since.

when the japanese started their car industry, they bought
from british, infact their first production car was an austin 7 clone
so the japanese drive on the left hand side. but they changed their
designs so that they could sell into the largest market in the world
at the time. along the way they changed the way in which
motor cycle gears were changed so that in the early
days of honda 450's particularly lots of guys got hurt changing
from their triumphs to the honda, and forgetting which was
the rear brake lever and which the gear lever. still a problem
for those riding classic brit bikes.

anyway end of rant :?

paul :wink:

 

[Paul Chapman]

we buy petrol in Litres

Most of us are now so confused we just put £30 worth in the tank - we stopped trying to work out what quantity that was years ago :? :? :?

Paul

 

[dedee]

Arn't there plans afoot to get us to drive on the right? As doing this overnight would be fraught with danger I seem to remember that a phased approach was recommended, starting with buses and HGVs.


Andy

 

[engineer one]

i thought that was the bus lane on the m4 :lol: :lol: :lol:

paul :wink:
can you imagine the accidents ?
we have enough with people driving the same way allegedly

 

[Scrit]

Aren't there plans afoot to get us to drive on the right? As doing this overnight would be fraught with danger I seem to remember that a phased approach was recommended, starting with buses and HGVs.

The Swedes made the move in 1967. For a number of years previously all the bus and transport companies were buying "convertable" vehicles and kits of parts. They then closed the roads from something like midnight Saturday until 6am on Monday to change all the road signs round.

For other "handedness data" take a look here

Scrit

 

[Niki]

Still you are lucky, In Poland the sell the petrol in Cubic Decimeter. First time, I had to think what is it till I came to realize that it's 1 Liter.

I just thought that it's more logical to read the length in units that are written on the measuring tape or ruler that I work with.

I was converted to Imperial at the age of 20 when I joined the aviation world, so in aviation I think in Imperial but in life, Metric.

niki

 

[misterfish]

I remember a few weeks ago watching (I think) the Great British Woodshop where David Free (?) was specifying that he needed something like 150 cms of '2 by 4'

I tend to be a bit like that having used both imperial and metric - I'm about to get a delivery of '4 x 2' C16 timber in 2.4 m lengths. I can think and work using both.

As an aside, my TS (Wadkin BRT) is all metric including the rip fence scale, but my Kreg mitre gauge is imperial. my mitre saw station uses some old free B&Q tape measures stuck along the top of the fence and they are both metric and imperial. I've never managed to find an adhesive scale in metric and imperial with 0 at the right hand end - imperial only is no problem.

Misterfish