any car..just a general question {not compulsory to select make/model here in Discussion - your earlier choice now removed DD}
i was just wondering was there a specific time when vehicle makers changed over to metric fasteners?
did europe have metric stuff before us?
Edited by Dynamic Dave on 12/07/2008 at 21:49
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I am SURE this is a wind-up. but...
Of COURSE the europeans had metric before Britain did - after all, they invented the stuff, to get away from those silly miles, pounds, fathoms, hogsheads, feet, inches and gallons
which always have some stupid 14 warts to the quangle, and 36 p******s to the sproat logic about them.
The metric system was introuduced after the french Revolution to 'clear' the old systems.
Same as Pol Pot did in Cambodia.
They even started their own calendar.
This 10, 100, 1000 system seems a tad more logical to me, but what do i know?
Litres per 100 km is far far easier to work out than MPG.
Also, I prefer 10, 11, 12 and 13 to 7/16ths, 3/8ths etc.
Having said that, apparently some vehicles made by Britsih LayDown used to have a mix of imperial and metric, at random...
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Bl did indeed use both imperial and metirc on some cars. So did ford, vauxhall, talbot and others.
Personally i much prefer metric measurements. I understand engineers are not so keen, but then they like things I dont too :)
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This 10 100 1000 system seems a tad more logical to me but what do i know?
Err; that's actually the decimal system and has nothing to do with the system of measurement based on the metre.
Decimals can - and were - used with Imperial too. Tenths of inches and even the ever-useful thou.
Metric dimensions may all interconnect beautifully; but they're impossibly awkward in real-life use. Most uses of measurement are single-value only.
Imperial units like feet self-selected from all the available alternatives like cubits and spans purely through common usage - the clumsy metric system has had to be forced on us by brainwashing children that there are no alternatives.
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was just asking about the nut/bolts not all manners of measuring systems
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Do American cars come in imperial measurements? All of the "septic" equipment I see is UNC/UNF threads and dimensions in ft and in and a perversion of the gallon.
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Yes; pretty much. They tried the metric system in the '70 and '80s but didn't find it useful or easy; so they reverted to what they know.
As the US is China's biggest market; they often use Imperial too.
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so reading these threads, i have a ford econoline e150, 1988 and need to get replacement bleed nipples/screws, am i looking at m/10 metric ones or 3/8 imperial, seems to be two different sizes and i dont know which ones to get???
Edited by purplejofm on 16/03/2011 at 14:03
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Thinking about it, it seems to me that vehicle 'metrication' started at about the same time that Japanese cars became popular. Back in the 70's mechanics had a toolkit of Whitworth (for morris minor) AF spanners and worked with Unified / Bsf threads. Datsun changed it all !
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Yup BL changed over in mid 70's TR7 uses imperial on the engine (designed much earlier) & Metric on the shell. My V8 was a nightmare, engine designed in the late 50's/ early 60's in the USA but mine was removed from a 1990 LR Defender so all external bolts Metric (alternator mount etc.) & all internal & those that bolted into tapped holes externally imperial. Change was early 70's for Ford as well Mk 2 Escort was predominately metric.
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Working in a garage in the late 70s I remember the 'foreign' stuff coming in with metric nuts and bolts.
As other posters have said, many cars around this time used both metric and imperial A/F (American Fine?) measures.
Every mechanic needed a dual tool kit.
Presumably, A/F is now more or less obsolete,
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A/F = Across Flats. A spanner designation - metric or imp. [17mm A/F is perfectly correct.]
The threads on late Imperial cars are:
Unified National Coarse - far superior to any metric thread in cast or alloy.
Unified National Fine - a finer pitch thread that the "standard pitch" ISO fasteners and much more resistant to loosening under vibration.
The Government spent millions telling everyone that metric was better - yeah, right!
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Wasn't there some foul up on the space program involving imperial/metric confusion, or is it one of those apocryphal tales?
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Wasn't fasteners, it was programming.
NASA use Imperial; but the software firm used metric and the Mars orbiter [travelling at 17,000mph] attempted to establish a stable orbit at 50 metres above the planet's surface - instead of 50 miles.
The only useful results from that $80m was that it established that Martian mountains are definitely harder than NASA probes.....
[The Martians considered the massive explosion an act of aggression and are building a retaliatory fleet even as we speak....]
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>>NASA use Imperial;
NASA used Imperial
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The Government spent millions telling everyone that metric was better - yeah right!
The metric system is vastly superior to the old Imperial system. It uses one unit for each fundamental physical quantity, without needing illogical conversion factors. For example, its easy to convert from cm to km; think how much more difficult it is to convert from say, feet, to miles and the possibility of errors creeping in.
I did a physics degree at a time when some Imperial measurements were still being used and they were a complete nightmare in complex calculations. No one in their right mind would want to go back to Imperial.
The metric system was actually proposed by the Royal Society in the 17th Century (should make the Europhobes feel better about it!) but it wasn't adopted in Britain. The idea was a simpler system that would make errors of calculation and conversion less likely. Lots of other countries toyed with introducing it, but the French did so first. They didn't actually invent it.
The metric system has been legal to use (in trade and commerce) in the US since the late 19th Century - so its perfectly legal to sell petrol in the US in litres, or sell sugar in 1kg bags.
Scientists in the US normally work in metric and then convert to Imperial units only where 'legacy technology' is involved. The US electronics industry, for example, used component pin spacings at 100thou and 50thou multiples (0.1" and 0.05") but the design software and component manufacturing systems work with the metric equivalent (i.e. 2.54mm) so a conversion has to be done. Virtually all of US industry is now converted to metric; it has to because of the number of joint ventures, e.g. Chrysler-badged Mitsubishi's, Euro-market Fords and GM cars being sold in the US etc etc. Canada, Australia, NZ etc converted many years back.
I think cars had a mixture of SAE and metric fastners when British and European components were mixed in the same vehicle (e.g. a Vauxhall Chevette body, designed in Germany, was fitted with the old Vauxhall 1256cc engine designed in England).
UNC is an American coarse thread based on English Whitworth (BSW). UNF is a newer name for the American SAE thread.
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Ford changed 1970 with Mk.III Cortina and T88 engine.
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Ford changed 1970 with Mk.III Cortina and T88 engine.
So I thought, until the temp. probe on my 1988-designed engine was rounding off with a 13mm socket, and required a 1/2". Also I could not find a suitable metric 'plug' for the hole to prevent coolant loss, so I assume that was imperial as well.
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Going off at a slight tangent, I'm pleased there's a school of thought that says that Imperial unit words will never leave our colourful language. tinyurl.com/6za6gq
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I would agree with most of the sentiments expressed above. As an Engineer, the use of Metric units is beyond question - try working with derived quantities such as moment of inertia or mechanical to electrical power or energy calculations in Imperial units. I know it can be done but it's clumsy and error prone.
As most of the above involves quantities for which there is no human "feel" it all works fine. The problem as Screwloose suggests is the practicality of units for everyday tasks where there is a definite human interface.
Despite being absolutely conversant with either system, if I'm putting up a shelf, I'll measure everything in inches. It's just too easy to get 2m 80 wrong by a factor of 10 in the sub-metre units. 5 ft 9 inches or whatever is instantly visualisable and easy to find on the tape measure.
To bring the subject back nearer to topic, does anyone know if the awful American offerings such as Chrysler Neons, PT cruisers and the like use Imperial fasteners?
659.
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Especially as most are built in Austria.
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Thread forms on hexagon headed fasteners are usually easily identifiable. Metric threads will often be stamped with the tensile strength of the fastener; i.e 12.9, 10.9, 8.8, 4.6 etc...the higher the number, the greater the tensile strength. Anything under 8.8 is not considered high tensile.
Just to confuse matters many automotive applications will use metric fine threads as opposed to metric course which will not be identifiable on the head markings.
Imperial fasteners used a lettering system instead of numbers. High tensile UNF & UNC were usually stamped with the letter "S" and/or three lines radiating from the centre of the head. BSW & BSF were stamped with an "R".
One useful tip to remember when using imperial fasteners is that BSW & UNC are the same thread, except for 1/2 inch.
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Whitworth thread uses a 55 degree angle. metric and unified 60 degree.
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To continue the 'amazing screw thread facts' thread (!), B.A. (British Association) threads have a metric pitch, being 0.9^n millimetres - where 'n' is the B.A. number.
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Craneboy, if my failing memory serves me right, 1/2" unc was the only unified thread compatible with a whit. thread.
The easy way to identify unified bolts is by way of the circular indent on the head, nuts by the circles stamped on one of the flats, or the circle around the thread on one of the gripping surfaces.
Edited by none on 14/07/2008 at 20:00
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Sorry none, but your memory is indeed failing you :-)
1/2" is incompatable because 1/2"BSW has 12 threads per inch and 1/2" UNC has 13 threads per inch. The thread angles are indeed also different, however the tolerance is so miniscule, that although perhaps not "best practice" engineers have been doing it for years to get themselves out of trouble.
Edited by craneboy on 14/07/2008 at 21:15
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Yes, but ------------ bah, I've forgotten now !
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Just to confuse matters many automotive applications will use metric fine threads as opposed to metric course .....
And then there are specials where the manufacturer has specified their own thread pitch.
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I would agree with most of the sentiments expressed above. As an Engineer the use of Metric units is beyond question - ...
Well, we successfully subdued a few stroppy European nations in two world wars without the need to go metric!
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L'escargot,
Which was better, then, the 88mm or the old 5 pounder?
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In 1972 in factory in the UK we through away 15tons of nuts and bolts of all sizes and descriptions still have a box full just in case.But don,t forget tyre diameter is still in inches or zolls.
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Tyre diameters are imperial but their width is metric!!!!
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When I did my automotive apprenticeship, I was using imperial at work,and metric at college doing my HNC. When working in F1 I was using imperial on the whole car with the exception of the engine, which was metric. This situation only changed recently with the majority of the car now being metric. There are still some imperial NAS bolts used on some suspension components, but the majority are "home made" titanium metric fasteners.I now work in the scientific research area. When we occasionally get equipment from the states, I am the only person who has imperial fasteners, tools, taps and dies etc.to fix them. Even our machine shop doesn't carry any and they have to borrow mine. To them its like an alien concept, whereas I can instantly switch from one to the other.
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Pre BMC takeover, MG engines (as in the TC,TD and Y type) had metric threaded bolts with Whitworth heads.
I've been told this is because Morris Engines was originally a branch of the French Hotchkiss company and continued to use metric dies and taps till 1955.
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Going back 45 years at Tech School in Rotterdam (I'm getting old) We grew up with the metric system but our Lathes wher made in the UK and we where turning whithworth threads.
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All Morgan 4/4 wheel studs are metric threads. So from 1936...
Same thread as a VW Beetle
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