Metric vs Imperial – Practical or Traditional?

[Ian AbbottParticipant @ianabbott31222]

Speaking of pizzas, which originally came from China, shouldn’t the dividing of such be undertaken using Chinese measurements.

 

The expert sitting across from me says that for linear measurements we’d be using 毫 (hao), 厘 (li), 分 (fen), 寸 (cun), 尺 (chi) and so on, which of course would only work for dividing around the circumference.  尺 being about one imperial foot.  To divide into segments 度 (du) would be the same as our degree.

 

That’s about as much Chinese translation as I can manage for one day.

 

Ian 

[Sam StonesParticipant @samstones42903]

While `helping’ with some paper hanging, my stepmother had her own standard.

 

A length of wallpaper, when measured from the ceiling to the skirting board was –

 

“Two rulers full, and half a screwdriver”.

 

Sam

 

 

[john swift 1Participant @johnswift1]

I Started of with imperial measurements and  thats how I visualise things

and given a free choice that what I use

 

but I use what ever measuring stick is appropriate

 

I’ve worked from drawings that started of with  imperial measurements

and had been updated by changing the stock dimensions to metric sizes !!!! 

 

a 1/4″ x 1/2″ x 3/4″ component became 6 x 12 x 3/4″   with

a hole for a BA screw at one end and a metric screw at the other

well done G.E.C

 

I must admit I’m confused by timber sizes being smaller then the stated size

but then again road tax is not spent on the roads

 

of more concern is seeing  work experience students  not being able to make the transition from centimetres to millimetres

 

 

                  John

Edited By john swift 1 on 08/10/2010 00:42:48

[chris stephensParticipant @chrisstephens63393]

Hi John,

I think I can point you in the right direction about timber size anomalies Traditionally the size quoted is the “as sawn” size. The reason planed timber is smaller is because some timber is lost in the planing., this to an “engineer” is of course a ridiculous state of affairs. Ain’t tradition wonderful?

chriStephens 

[WolfieParticipant @wolfie]

I can work in both Imperial and foreign as should any engineer be able to. I prefer Imperial, but am just as happy with metric as long as its expressed in mm.

 

But thats only the length units. What the hell is a kilogram?? And why can I still buy 2 metres of 4 x 2? 

 

Oh well 576ml of lager please gaffer!

[Anonymous]

Wot? Lager! What’s wrong with a good bitter. None of this foreign stuff thank you!

 

Andrew

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Andrew, a good bitter anyday.

 

Regards Nick.

[john swift 1Participant @johnswift1]

welcome to the forum Wolfie

 

all I know is my 1 lb of sausages has to labled   ” 454g    1 lb   e “

to keep the jobs worths happy

 

I have to agree with Andrew and Nick

 

its a pint of bitter for me

 

 

              John

[Axel BentellParticipant @axelbentell]

Funny how important our respective languages are to us. We feel lost when we cant use the expressions we “allways” used, but have a think, arent there remnants of old units of measurements (and other things too!) in todays language that are totally alien to us? At one time people must have thought the same way when they stoped using those units…

 

Have all the pints you want; but you are a fool if you keep using Imperial units today in the shop!

[KWILParticipant @kwil]

“you are a fool”  Why? We can call it whatever we want surely? The only thing that is alien are the outsiders who wish to impose their ways.  [Yes I can work in both and other systems as well as differing weights but that does not make me change my opinions]

Edited By KWIL on 25/10/2010 09:06:08

[Anonymous]

Well said KWIL! Mind you, in my experience, shop assistants don’t understand either measurement system. How much pork pie do I want? Two inches, blank look; err, 50mm, blank look again. This much, indicating with finger and thumb. They then select half that distance, so you have to keep saying bit more, a bit more, until it’s correct. Rather like Bernie, the bolt, for those who remember the Golden Shot.

 

And we can buy cheap beer in any measurement unit without having to go to Denmark.

Regards,

Andrew

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, hear, hear! Kwill and Andrew. One may not like a particular system, that doesn’t make any other system or anyone who uses it a fool, espcially when a system has been and is still in successfull use for longer than any of us who are debating it. Why should anyone be a fool for using any system they feel is justyfied for themselves.

 

Regards Nick.

[DMBParticipant @dmb]

Hi all,

 

A long time ago I purchased a Clarkson milling chuck in its box and 4 Imperial sized collets. My reasoning was that all the exbn. tool stands were flogging 2nd hand endmills and slotcutters in Imperial sizes in large quantities,probably because they were being got rid of by industry on the cheap to tool dealers. I thought that I could buy metric collets later, if and when needed/forced to. This has worked well, since I am still using above collets and cutters for most designs in the mags are still Imp. and it doesnt of course matter whether a 5/8D cutter is used purely for fast metal removal or if its 16mmD.

In the past I have cobbled-up Tee nuts and studs + odd washers to do whatever job was in hand. Now I plan to put all those bits on one side in a spares box for when/if I need extra clamping. At the present, I am making a proper set of studs, nuts and extensions, all in 8mm thread, so I can simply buy hex. nuts to fit tops of the studs.

Likewise with any thing else where I think about future needs when only metric nuts and bolts, screws will be easily available, I now choose metric threads.

The exception of course, is on my models where I will continue with whichever thread has been traditionally used.

John. 

[chris stephensParticipant @chrisstephens63393]

Hi Axel,

I know you are only trying to be provocative with your statement, but even so I think you are the fool for offering such blatant exaggerated rubbish. The one and only fault with Imp lengths is the use of fractional sizes and that only because micrometers don’t come marked in fractions. 

On the subject of micrometers,  we all try to work to the finest graduation on our instruments, in most cases one thou on IMP and 0.01mm on a metric. It is much easier to work to units 2.5 times larger (IMP) and still be accurate enough for most of our needs. Now which is better?

chriStephens 

 

[Gordon WParticipant @gordonw]

I do get fed up with this metric /imp. stuff, the bit you make is whatever size it is, do agree about centimetres tho’. When I was an apprentice one test was to bore a hole for a given ball race (about 2 ” dia,) with only an outside and inside set of calipers, what size was that hole? Must say I surprised myself doing that one. Andrew please, where is this cheap beer?

[John CoatesParticipant @johncoates48577]

An interesting thread

 

As a newbie who has never done any engineering beyond re-assembling motorbike engines and their tolerances, I have been having fun trying to establish in my mind the value of thou’s.

 

I have just got to the point where I can visualise 40 thou being one millimetre and work things out from there with one thou being 0.025mm but thats too small for me to grasp as a concept

 

Having a metric mill and an imperial lathe means I am going to have to be able to interchange dimensions in my head.

 

The lathe will be enhanced by tooling with imperial threads to fit to the 5/8th holes in the cross slide. But I’m with John Coleman and am making up a set of new T-nuts to take standard M8 threaded bar as the 3/8th set I bought doesn’t have the right lengths for my milling table or vertical slide

 

And as for beer I prefer ale

 

“Why are pirates? ………………. because they aaaargh” 

 

[Axel BentellParticipant @axelbentell]

First of all I want too apoligize, it was a word badly choosen, too early to be properly respectful I guess when I wrote it. I´m very sorry!

 

To be accurate is easiest with a metric micrometer. I was taught to use an Imperial when I got my training in the USA. I have used both in professional circumstances. Often one needs to “split the lines” on a mic and guess a little, putting the thimble (barrel that turns) between two lines. you get a finer increment on a metric, than on the Imperial one, and it´s alot easier to read a metric mic, there´s alot less mental work to it!

 

The world of mensuration is larger than our micrometers though. When we get to do calculations, its alot more practical to have 10 as the base rather than all of the Imperial units that come out as unmanageble decimal numbers from the fractional form.

 

There was an interim unit of measurement here in Sweden, that used 10″ to 1`, this was just a segway to metrification. I have a nice folding steel rule with that unit on one scale, made in Sheffield!

Edited By Axel on 25/10/2010 15:10:49

[Anonymous]

Hi Axel,

 

No need to apologise, to me at least, it was taken in good humour on my part. I appreciate that the British sense of humour can be somewhat confusing!

 

Gordon,

 

I’m afraid the cheap beer is in relative terms rather than absolute. The first time I went to Sweden not only was the beer expensive, but the price went up after 9pm. So, at 8:50pm we ordered three beers each; the waiter wasn’t impressed, but he did bring them.

 

Regards,

 

Andrew

[KWILParticipant @kwil]

My small metric mic can indicate 0.001mm that is a whole 4/100 of 1 thou. Good enough for me!

Edited By KWIL on 25/10/2010 16:40:59

[Sub MandrelParticipant @submandrel]

Hmm, 1 uM, that’s two wavelengths of red light. I hope you have a fine ense of touch when adjusting your mike Kwil!

 

Neil

[Anonymous]

Blimey, 1µm indeed. You’d only need a mouse to fart in the workshop and that’d warm things up enough to change the reading!

 

Regards,

 

Andrew

[JasonBModerator @jasonb]

Your mic may have a resolution of 0.001mm but whats the accuracysome with the same resolution can be + or – 0.004mm so really you are only reliably reading to 0.01mm

 

Mine will read to 0.001 with 0.001mm accuracy but I do tend to prefer using my old Mitutoyo to the digital one.

 

Jason

Edited By JasonB on 25/10/2010 20:04:15

[Mark DickinsonParticipant @markdickinson21936]

I left full time education in the early 90’s having been taught to use the metric system. Then I entered the real world…

I measure length in millimeters but distances in miles.

I used to buy fuel in gallons but now buy it by the litre, I measure fuel economy in mpg.

Fuel price used to go up a penny a gallon, now it’s a penny a litre.

I buy drink by the pint.

My cars engine capacity is calculated to the nearest tenth of a litre. Its wheel size is 16″ but its tyre width is 235mm.

My Land Rover uses metric, unf, unc, and whitworth threads.

I can visualise a gradient of 1:6, but a road sign saying 17% means nothing to me.

I work in IT where a byte could be 8 bits, but then again it could be more. A kilobyte to me is 1024 bytes, but should be 1000 according to the SI standard. My 500 gigabyte hard drive should actually be a 500 gibibyte hard drive. So that will be 500 gib then (is that pronounced gib or jib)

I’m sitting here in front of my 22″ monitor typing this

There are only 10 types of people in the world — those who understand binary, and those who don’t

Since taking up “model engineering” I’m having to deal with imperial fractions, imperial decimals, number and letter drill sizes.

 

People wonder about my vaguely confused expression……

[Sub MandrelParticipant @submandrel]

One thing people seem to ignore is that fractions make designing things very easy. Using squared or lined paper I find it very easy to design things using stock sizes, much easier than working in mm in which I end up needing non-preferred sizes.

 

Neil

[John OlsenParticipant @johnolsen79199]

Mark…A byte should always be 8 bits. A word will be a different length depending on the actual computer system in use, and need not be a  power of two although they usually are.

 

Neil, I don’t know that I completely agree with you on that….since the material I can get tends to be a mixture of Imperial and metric sizes. The machines I own are also a mixture of Imperial and metric.  Luckily the CAD system I am using will accept input like :

3/16

3+13/32

17/32+9/64

5/25.4

25.5 * 3/16

 

It does the arithmetic for you. 

You can also draw in one unit and then change the whole drawing to the other, although this is not a very practical way of converting a design. Well, actually I guess it depends on the nature of the conversion you need…if you are working on an Imperial design, using Imperial stock, but machining on a metric machine it could be useful. (Or vice versa I guess)

 

regards

John

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