Forum sponsored by:
Metric vs Imperial - Practical or Traditional?
| Stub Mandrel | 29/10/2010 20:49:21 |
 4318 forum posts 291 photos 1 articles | I was in school when they metricated the curriculum. What's the old saying? Metric for business, thous for precision but imperial fractions for pleasure? Neil |
| Chris Trice | 29/10/2010 21:20:48 |
 1376 forum posts 10 photos | That's OK Nick. I'm not suggesting anyone should abandon imperial. I'm just saying that the march to metrication is inevitable and that imperial can not offer any kind of spirited defence other than people who already use it liking it solely for it's familiarity. It would be interesting to ask those who use DRO's on their lathes or milling machines, which system they tend to use most or even when using a digital caliper? I like imperial but still tend to work in metric. |
| KWIL | 29/10/2010 23:22:51 |
| 3681 forum posts 70 photos | I have industrial DROs on all my machines and I switch between Imperial and metric just to suit what I am doing. I have a metric Harrison M300 lathe and Bridgeport, but also use them in Imperial. I can feel and see a thou or 5/10ths but I am damned if the same applies to 0.01mm |
| Chris Trice | 30/10/2010 11:23:38 |
1376 forum posts 10 photos | Not surprising as it's just under half a thou but the point is well made. People have a sense for what certain measurements are. That's the familiarity bit. I've found one of the best things for getting a sense of 0.1mm is to compare drill bits that step up in 0.1mm steps. It's then easier to visualise in your mind what 0.01mm represents. But as mentioned, familiarity with an old system doesn't mean it's better than the new. Just familiar. Another example which a few here of my generation can probably relate to. Letter and number drills: I'm sure that to those brought up on them, they're familiar and easy to appreciate in the minds eye. To me personally, they mean absolutely nothing and the system gives zero indication as to their actual size. It's completely abstract. If one were quoted, I'd head straight for a set of tables to find out what the 'real' size was and use that. Basically anyone over the age of forty will be familiar with imperial being more or less the last generation to use it but there are people I work with in their twentysomethings who stare blankly at me if I throw them an imperial measurement. Edited By Chris Trice on 30/10/2010 11:25:04 |
| Chris Trice | 30/10/2010 11:30:21 |
1376 forum posts 10 photos | And another:
How many grams in 2KG?
Easy Peezy.
How many ounces in three stones?
Not so easy.
How many thou in 7/64th?
Brain burp. |
| TomK | 30/10/2010 11:39:53 |
| 83 forum posts 23 photos | How many thou in 7/64 easy devide 7 by 64 = 0.1094 rounded to 4 decimal places   |
| Andrew Johnston | 30/10/2010 12:27:05 |
 7061 forum posts 719 photos | Martin, I assume that the terms for the various aviation types definitely came from the nautical world. As did originally the nautical mile. However, it's use in aviation is probably more to do with the fact that it is approximately 1 minute of arc on a meridian, so it ties in neatly with lat and long, and makes navigation calculations a bit simpler. Regards, Andrew |
| Dinosaur Engineer | 30/10/2010 13:58:29 |
| 147 forum posts 4 photos | As long as the older American planes are flying, there will be an imperial system which will be quite a few years yet and also camera makers will continue to use Whitworth tri-pod mounting holes in their cameras. I'm sure that there are many other imperial uses/users that will continue for a long time yet. |
| Andrew Johnston | 30/10/2010 15:01:24 |
7061 forum posts 719 photos | The international air transport system is imperial. Heights, and flight levels, are in feet QNH, which itself is in millibars. Speeds are in knots. Lower down the scale there are of course differences. The US tends to use inches of mercury for pressure settings. Europe uses kph for speed and metres per second for vertical speed. They also tend to use metres for height too; metric altimeters are just plain weird! Airspeed in knots, mph, kph, I can cope with that, but metric altimeters, aaaaargh. It's even dafter than it appears; I've just looked at my low level French aeronautical map of the Alps, and all the heights are in feet. One up to the Brits! Regards, Andrew |
| Terryd | 30/10/2010 15:04:25 |
 1946 forum posts 179 photos | Dear Tom K, I'm impressed if you did that in your head as fast as I can work out grammes in a kilo!  Try working out accurate areas or volumes when using feet and fractional inches, my brain explodes every time. I'm 63 by the way and use metric in preference, despite being expert in imperial including the use of barley grains (3 to the inch when taken from the middle of a ripe ear of barley). I started teaching engineering metalwork in the early 1970s just as metrication became legally adopted system (before membership of EU) so the youngsters would be in their 50s by now and should be au fait with metrication. Interesting to note that parliament accepted the need for metrication and standardisation in the 1860s but several wars and Conservative MPs got in the way and overruled the scientific and engineering lobby of the day. One conservative MP even went so far as to object on the grounds that the kilo was too heavy for the British housewife. A greengrocer complained that the pound was convenient as he could pick up a pound of potatoes with one hand - didn't matter that two handfuls were about a kilo or one hand was half a one. That's the sort of rubbish that gets dragged out when entrenched opinion is allowed to rule over logic. As an aside, another less well known fact is that the Florin or two shilling piece was introduced in the 1840s as the first stage in decimalisation of our currency (1 Florin is 1/10th of a Pound Sterling for our younger readers ) But that was stymied by the same sort of reactionary forces at work (and the Daily Mail didn't even exist then!). I think that Toffs hated the thought of the disappearance of the guinea. By the way Dino engineer, I don't really care if the Americans prefer to stay in Pre Medieval Europe, it's about time us who wish to join the 21st century just got on with it. I am of course talking about the inhabitants of the USA not of the majority who live in Central and Southern America |
| chris stephens | 30/10/2010 15:33:24 |
| 1049 forum posts 1 photos | Dino,
Oh yes, like pipe threads, although the continentals leave out the "inch" part and just call it 1/4 or 3/8 with no ", they are he same.
chriStephens
|
| Stub Mandrel | 30/10/2010 15:48:01 |
4318 forum posts 291 photos 1 articles | I can't help feeling that, for some of us, using imperial units is part of the whole experience of model engineering. Every hobby has its rituals and paraphernalia - not to exclude those who don't know, but as a sort of bond for those who do. For me working in imperial means more than just a choice of measurement system (and to be honest I don't care which I work in, I'm fitting flooring today and decided to work in inches simply because I picked up the old stanley tape which hasn't got cm on it, not the new one) it means I get to use old stuff and it means I'm using the same system as teh men who built the originals. If I built a French model I'm sure I'd use mm, even if the ednd result is identical. Neil |
| chris stephens | 30/10/2010 15:56:15 |
| 1049 forum posts 1 photos | Hi Terryd,
"By the way Dino engineer, I don''t really care if the Americans prefer to stay in Pre Medieval Europe, it''s about time us who wish to join the 21st century just got on with it. I am of course talking about the inhabitants of the USA not of the majority who live in Central and Southern America"
Tell me, as you want to be in the 21st Century, I must assume that you only make models of Nuclear Power Stations or Fuel Cells or some other "modern" stuff, and never touch anything related to steam engines or other old technologies.
The trouble with being modern is that modern keeps changing, even the metric system. When we started going metric we did not use the SI system but (if memory serves) the CGS one. How long before some brain box with nothing better to do comes up with a system based on references from "Lord of the Rings"or HG Wells, or to be more modern perhaps "world of warcraft"
chriStephens
|
| Chris Trice | 30/10/2010 16:48:39 |
1376 forum posts 10 photos | The last two posts really illustrate the core reasons for imperial within the hobby. The hobby is mostly based around replicating things by a scale factor that were built to imperial dimensions in the first place. It's a throwback to a bygone era, something we enjoy the nostalgia of. Unfortunately, the rest of the entire engineering world and wider industry is not driven by the emotional but by logical sense. The funny thing is, I mostly build replicas and components for things that are space related but for the same reason in that the originals were built with imperial materials but steam locomotives and traction engines have never been an interest for me. My main job is in the film business building animatronic rigs and that work is 99% metric. The only time an imperial component gets used is when there's no metric alternative immediately available. Others can source an overlooked M6 screw virtually anywhere, a 1/4" Whitworth is a struggle even assuming someone has the knowledge to recognise it. |
| Chris Trice | 30/10/2010 17:01:02 |
1376 forum posts 10 photos | The other story I tell purely for interest was I did a film in Montreal, the most French quarter of Canada eleven years ago. Although the inhabitants in and around Quebec represent only ten percent of the Canadian population, they fiercely insist that much of Canada is bilingual such as road signs being in french and english across the entire country. I took all my metric taps and dies assuming that metric nuts and bolts were going to be the norm. I was`stunned to find that even there, they were still using archaic imperial threads and it was actually a struggle to find metric machine screws at all. I remember explaining to the Canadian crew how the metric system of screw threads worked and even they said what a brilliantly simpler system it was. |
| Martin W | 30/10/2010 17:06:11 |
| 940 forum posts 30 photos | Andrew
Using the nautical mile while travelling due north/south on the meridians or perhaps east/west on the equator (well nearly) is fine but out come the sine/cos tables for trogging around the latitudes
! Thankfully when they moved from the millibar it went to a direct equivalent of hPa otherwise there would have been trouble at the mill as they say . Cheers
Martin
PS
Terryd.
I use metric and can best your age by some 3 plus years, must be the old dogs and new tricks syndrome or something to do with the number of fingers plus thumbs I have. Fingers only and your into octal and that takes me back to the first mainframe system I worked on. |
| Andrew Johnston | 30/10/2010 21:41:24 |
7061 forum posts 719 photos | Martin, Of course you are correct about needing spheroidal geometry, but aeronautical charts on a small scale, say southern England, have a distortion such that distances and true headings are correct within the normal navigation limits without the need for trigonometry. Any map must have a distortion, as it is a flat sheet representing a near spheroidal shape, but some distortions are more useful than others. I'm not sure if the CAA charts use Mercator or Lambert mapping; my southern England chart doesn't say. Regards, Andrew |
| Ian S C | 31/10/2010 02:00:29 |
 7468 forum posts 230 photos | Andrew, if the british maps are the same standard as our NZ ones, they will beTransverse Mercator projection. he altitudes are in colours, in whole hundreds of feet, and the meters as conversions of those feet. Distance is in nautical miles, with a metric scale included. Runway lengths in feet. Mind you this may not be fully up to date, my newest map is dated 1980, but NZ was well into metrics then.Ian S C |
| Terryd | 31/10/2010 07:45:11 |
1946 forum posts 179 photos | Hi Chris (Stevens), It was not only the British and Americans who made steam engines etc in the past. The 'Continentals' made them too and they were mostly Metric. We would also have used metric if the decision made in the 1870s for the UK to adopt the system had been followed through. As for the literary references you make, I hope that you really think that the metric system is somehow thought up by some eccentric individual. It is a very carefully developed system based on natural phenomena and governed by the Conference which represents almost 80 nations. The metre was originally based on the length of a meridian of the Earth, The gram is the weight of one CC of pure water at a given temperature. I personally think that is better than a system based on grains of Barley. As for the changes in the system, the SI standard now used was adopted in the 1960s to overcome the problems of the differences between the scientific and engineering systems. The Imperial system was not impervious to change. I remember the fps system which added the poundal and later the slug (and slinch). Frank Hornby (the developer of Meccano) wanted to use the metric system as the basis for his invention but was foiled by the lack of availability of metric components in the UK so he had to use an imperial system. His later developments used metric For those Francophiles amongst us, a decimal system based on a universal measurement (as the Metric system), to replace the ad hoc inch/foot system, was first proposed formally by an Englishman (Wilkins) in the second half of the 17th century. As far as the USA is concerned, remember that NASA uses the SI metric system, as does the scientific community |
| John Olsen | 31/10/2010 07:47:24 |
| 1294 forum posts 108 photos 1 articles | Having just been playing with some Imperial drawings...if Imperial fractions are so useful and versatile, why was it necessary to invent not one but two separate measuring systems for the sizes of drills and of wires (and sheet material). So when I want a hole to take a certain piece of wire, I have to go and look up the SWG chart, find the size, then go and look up the drill chart, and find the number of the drill that will make a hole that the wire will fit in. The same applies of course with BA screws, although at least there if I am working in metric I can find the diameter by multiplying 6mm by 0.9 to the power of the BA number. Imperial fractions might be good enough for carpentry but they are just a mess for serious precision work. regards John |
Please login to post a reply.
Magazine Locator
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
Sign up to our Newsletter
Sign up to our newsletter and get a free digital issue.
You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy
Latest Forum Posts
- *Oct 2023: FORUM MIGRATION TIMELINE*
05/10/2023 07:57:11 - Making ER11 collet chuck
05/10/2023 07:56:24 - What did you do today? 2023
05/10/2023 07:25:01 - Orrery
05/10/2023 06:00:41 - Wera hand-tools
05/10/2023 05:47:07 - New member
05/10/2023 04:40:11 - Problems with external pot on at1 vfd
05/10/2023 00:06:32 - Drain plug
04/10/2023 23:36:17 - digi phase converter for 10 machines.....
04/10/2023 23:13:48 - Winter Storage Of Locomotives
04/10/2023 21:02:11 - More Latest Posts...
- View All Topics
Support Our Partners
Shopping Partners
Subscription Offer
Latest "For Sale" Ads
- Reeves** - Rebuilt Royal Scot by Martin Evans
by John Broughton
£300.00 - BRITANNIA 5" GAUGE James Perrier
by Jon Seabright 1
£2,500.00 - Drill Grinder - for restoration
by Nigel Graham 2
£0.00 - WARCO WM18 MILLING MACHINE
by Alex Chudley
£1,200.00 - MYFORD SUPER 7 LATHE
by Alex Chudley
£2,000.00 - More "For Sale" Ads...
Latest "Wanted" Ads
- D1-3 backplate
by Michael Horley
Price Not Specified - fixed steady for a Colchester bantam mark1 800
by George Jervis
Price Not Specified - lbsc pansy
by JACK SIDEBOTHAM
Price Not Specified - Pratt Burnerd multifit chuck key.
by Tim Riome
Price Not Specified - BANDSAW BLADE WELDER
by HUGH
Price Not Specified - More "Wanted" Ads...
Get In Touch!
Do you want to contact the Model Engineer and Model Engineers' Workshop team?
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.
Digital Back Issues
Donate
Register
Log-in
Model Engineer Magazine
- Percival Marshall
- M.E. History
- LittleLEC
- M.E. Clock
ME Workshop
- An Adcock
- & Shipley
- Horizontal
- Mill
Subscribe Now
- Great savings
- Delivered to your door
Pre-order your copy!
- Delivered to your doorstep!
- Free UK delivery!
All Forum Topics > Beginners questions > Metric vs Imperial - Practical or Traditional?