Metric system

enjenjo · November 20, 2009, 06:16:08 PM

How much do you use metrics? I have a background in testing, where we used metrics exclusively, so I am comfortable with it. Many new parts are now coming metric, where in the past they were imperial. When measuring, I often use a metric rule since a lot of measurements that are oddball in imperial, are even in metric.

For volume measurements, I still use imperial, since that's the way it's packaged. Except for soda.

Many parts we have used for years are actually metric. For instance the most common driveshaft U joint is listed as a 1.063" cup size, which is actually 27mm. Model A wheel bearing are metric also.

Just curious

Danimal · November 20, 2009, 07:06:07 PM

I'm more familiar with metric when I do my steel thickness and such because I've been in automotive for 17 years. I never learned gauge. I can do temperature pretty quickly as well as a few others. Volume rarely. Weight fair. Pipe diameter I'm rusty on because I've been dealing with the jack division for 5 or 6 years now and have fallen away from some of that. 2" is 50.8, everything else is pretty much 6 mm per 1/4" from there plus or minus so if they tell me what it is in mm I can usually get there.

Not as well as you do, Frank, but you have some good links that you keep in your head and if I could learn those, it might help me at times.

Danimal · November 20, 2009, 07:08:34 PM

And don't forget paper. A4 is NOT Letter size!!! You can't fax it, you can't scan it, you can't print it unless you convert it or you have it! The company I work for is based in Europe and ALL of our forms are set for A4!! I got * and bought a reem of it and printed masters out because the * things kept jamming the printer if you forgot to tell it to convert to Letter!! Now I copy the masters and let the copier chop off the other parts!!

Tolle · November 20, 2009, 07:10:27 PM

Hi, as an answer if you can count to 10, you can comprehend the whole metric system. Canada is trying. X-mas greetings. Tolle Denmark

Carnut · November 20, 2009, 09:21:19 PM

Heh, heh, I have never done much with metrics.

I only have one vehicle that has obviously metrics on it and that is my PT Cruiser which fortunately hasn't needed much service.

My 89 Silverado may have some metrics mixed on it, I know my Bro tried to disassemble the top end of the engine a couple months ago and he used metric wrenches/sockets to do it, but when I started to help reassemble it I noticed everything was really US and he had just been fudging things.

Everything else I have automotive is essentially 'premetric' except as you noted some things in inch fractions may actually be metric and I've never noticed.

Harry · November 20, 2009, 09:42:14 PM

Canada went metric in 1978. I love it. It's so easy to work with.
USA has been using metric for years. Your money is metric. 100 cents, etc.
100 centimetres in a metre, 1000 centimetres in a metre.
It's easier to work with if you don't try to convert to English.

jaybee · November 20, 2009, 11:55:04 PM

IMO we'd get used to metric much easier if American cars were truly metric, but most of them are a mix of metric and Imperial. Makes it damned annoying when you're humming along in one, reaching for wrenches and making steady progress without much thought, then all at once none of your wrenches seem to fit until you grab one from the "other" set.

wayne petty · November 21, 2009, 12:59:34 AM

i think going metric was a plot to sell us more tools....

now along the the fractional sae sizes.. i have a full box of metrics..

what gets really complicated.. it metric thread sizing..

so instead of course and fine... now there are 3 or more...

so in 8mm.. you get 1.0 and 1.25
in 10mm you get 1.25, 1,50, 1.75

with 12mm i think you get 4 thread pitches..

then throw in the odd sizes... just to spite us.... 9mm 2 pitches.. 11mm 2 thread pitches.. i have not run into 13 mm yet... but i know that will be a dark dangerous day in the world of automotive repairs..

lately.. i carry around my metric sockets... and a metric hammer to force them onto the sae fastener heads...

oh... and if you notice.. that some fastener heads have been shrinking.. that is a weight saving measure... reduce the finished weight of the car anywhere they can... the smaller headed fasteners also cost less in material..

zzford · November 21, 2009, 08:50:41 AM

I spent my first 25 years as a VW mechanic so I'm pretty used to it. For the last 16 years, it's been mostly fractional working on Internationals, but that is changing, too. I do still find myself thinking "let's see, I need a 11mm open end for that bolt", when it really has a 7/16" head on it.

Danimal · November 21, 2009, 10:55:14 AM

I fight with the GM engineers all the time. I supply jacks and tools. They constantly want to order wrenches based on the wheel stud. "I need an M12 or an M14 wheel wrench."

The argument I have is two fold:

You don't go to Sears and buy a wrench based on bolt size but HEAD size. M17, M19, or M22.

They aren't consistant globally with their head sizes! An M12 wheel fastner in Europe uses an M17 (because they use Wheel Bolts still!) and in the US we use wheel bolts so the NUTS are M19. They have finally made a "Global" standard to go to wheel studs on all new cars at M14 using an M22 wrench but that won't be in full effect until 2014 or so.

So now you know why you get such a mes under the hood of any of them!

OldSub · November 21, 2009, 01:58:14 PM

For a long time I figured there were two kinds of vehicles, ones I could work one, and ones with computers. The advent of computers in cars and the addition of metric fasteners happened close enough together that I dealt very little with the metric stuff. Since I've been pretty biased toward Chevrolet and GMC my old stuff has been pretty pure SAE.

Then I paid an outrageous labor bill for some work on my '85 Corvette for work that didn't touch the computerized parts of the car. Now my attitude is if its under warranty the dealer get its. Otherwise I'll work on it and buy any tools I need.

So I've now got a drawer full of metric wrenches and sockets complementing all the SAE stuff I've collected over the years.

My bias against computers has been that I deal with them all day at work, I don't want them souring my hobby. I've gotten over that to some degree.

chimp koose · November 22, 2009, 01:41:51 AM

If God had wanted the world metric, Jesus would have had 10 desciples! .01mm is too small of a division to mean anything when I am machining stuff. I am Canadian, we are metric,I still tell fuel economy in MPG,we ALL tell you our newborn baby's stats in Pounds and inches. I still buy 2x4s at the lumber yard and my house is 1040 sq FEET!We canadians are probably better at math than most americans because we have been doing metric/imperial conversions in our heads for the past 30 YEARS! 39.37 inches to a meter,4.54 l to imperial gallon,2.21 lb/kg 1.6km/mile 25.4mm/inch . And the best one.........0 degrees C =32F 10C/18F so take the temp in C X1.8 then add 32=F If I was a scientist(which I am not)I would LOVE the metric system as it is easily used to determine weight/volume/temperature/energy conversions just by sliding a decimal point. Good for some,not for most.Sorry for the rant.Im sure there is a conversion for my blood pressure too!

Mr Cool · November 24, 2009, 07:45:23 AM

So Im guerssing you guys dont see the british system then?
BSW, or just whitworth to us throws everything you ever knew about wrenches and sockets out the window. Be very thankful you dont have to work with it, fortunately we dont see much either, but when you do it really upsets you, because metric doesnt fit, and neither does imperial. :evil:
We have alot of both "normal" systems here so conversion is straightforward, although we rarely see temperature if F.

Rrumbler · November 24, 2009, 03:22:29 PM

USE metrics?? Not willingly. My brain thinks in feet, inches, quarters, eighths, and so on, and decimals of those measurements. In weights and volumes, no dice - I am lost. I guess I fit the mold of "Luddite" as it concerns these subjects. When I am confronted with a metric wrench or other linear measurement, my mind tries to convert it to inches and such; for example, 17mm is about 3/4 inch, at least a 3/4 inch wrench will work on a 17mm nut or bolt head. Beyond that, I always had a couple of "cheats" in my pocket or tool box: a six inch rule with mm on one side and inches on the other and a slide that correlated the two, and a small sliding caliper that did the same thing. I also carried a "Pocket Reference" book, so I was pretty well covered if I needed the help. No matter how hard I have tried to adapt, it has not worked; if I was told today that there would be no more inches and feet, only meters and such, I'd still try to convert in my mind - it's just built into me.

taxpyer · November 24, 2009, 04:32:45 PM

It's all a pain in the *. I live in Canada and yes we changed but only because big brother made us. We're all used to it now and have two tool boxes to prove it. No worse than putting up with philips head screws or torx screws. On the other side of the coin,,, you can buy more tools! Now thats got to be good news!

Quote from: "enjenjo"How much do you use metrics? I have a background in testing, where we used metrics exclusively, so I am comfortable with it. Many new parts are now coming metric, where in the past they were imperial. When measuring, I often use a metric rule since a lot of measurements that are oddball in imperial, are even in metric.

For volume measurements, I still use imperial, since that's the way it's packaged. Except for soda.

Many parts we have used for years are actually metric. For instance the most common driveshaft U joint is listed as a 1.063" cup size, which is actually 27mm. Model A wheel bearing are metric also.

Just curious