I chose SAE, because when looking at any bolt head, I know what size it is SAE, unless it's metric. Then I have to go in the basement and get out the metric tool box.

It's nice being able to shout to dad 'bring me the 7/16" socket' and knowing that's the size you need. I know metric conversion is easier for the most part, but all those 0's can get confusing even for math geniuses. Miss or add one and you're screwed. With SAE, you just know the sizes. Maybe I just need more work on metric stuff. I tell ya, putting together my little sister's bike was a pain until I discovered that I needed metric sockets.

And think about the metric sizing for tires. MM, %, and inches all in one. With SAE its all inches.

Just one more thought... Do they have ratchets that are in metric? All I know of is 1/4"or 3/8" or 1/2" with metric sockets. Could somebody please tell me if they use 10 mm ratchets overseas? Or do they stick with the 3/8"?

 

I have often wondered about the drive sizes also. I would guess that in other countries they would use a metric drive though. The only time I have problems is when metric and SAE are both being used on the same vehicle. I found after a little while that when you had one that was all metric is became fairly easy to know what the size is, especially when some cars use a few sizes pretty much everywhere. I have a conversion chart on the garage wall on a 4 X 6 card that lists the decimal size so that it is easy to figure out what it is when they are mixed up. I now have one roll away for SAE and one for metric. I also have a peg board that I have the most common metrics hanging on so they are easy to get to. It really isn't hard though.

 

Metric all the way even tho I have more SAE taps and dies but my metric supply is growing. As far as tools go I carry a metric set because I can wrench on SAE with that but the SAE tools will not work on some metric fasteners (10MM for example). The Metric tools have much finer increments.

I do have a large selection of metric heli-coil tooling since most modern stuff is made out of that butter soft junk pot metal crap called aluminum. I never needed many heli-coils with the cast iron parts.

 

Back about 1973, I decided to build boats for a living. At the time, experts said that the US would be fully metric in 10 years, so I designed and built all my boats using metric standards. Well, those conservative old New England fishermen would ask me how big a certain boat was, and I'd say "5 meters". Well, then they look at you funny, 'cause you're obviously some kind of commie. I actually had to measure a boat with an SAE tape measure, because I didn't actually know its size in feet and inches! We are the only sizeable country that is not fully metric; this half-way crap is for the birds! Why would we use a system based on the size of some guy's arm, or the length of three barleycorns? I got metric training at a job, learned to read metric blueprints, metric micrometers, etc., and it's no big deal. It's a much better system, with lots of convenient shortcuts. For example, to select a tap drill for a metric thread, simple subtract the pitch from the diameter. It works with SAE taps, too, but you don't have the pitch given in a single unit (quick, what's the single pitch of 13 threads per inch?) With metric, the pitch is given. As far as the actual bolts are concerned, it makes little difference as long as the grade is equivalent. I know it's hard to acquire a 'feel' for metric after years of SAE: I'm 52 years old. It's like a second language; Chinese isn't hard to speak if you were brought up on it!

 

there is no difference in the number of grades SAE grade 2,5,8 metric gr8.8,10.9,12.0 they are the same hardness levels

 

I find that the metric system makes more sence, but SAE and the inch/pound systems are easier to visualize.

There's no 'handy' metric equivilant for one foot or one gallon, for instance. I use both systems in my garage because I'm forced to by the manufacturers, but I consider it a pain. When I'm cooking, I can visualize what a teaspoon or a 1/4 cup is.

Maybe I'm just an old fart, but I don't like using the metric system.

MR

 

MrOldV8 has said it best - the old imperial (SAE) system, with its inch/foot/yard, was a system based on the human body. It largely remains in the world of shipping & aviation - a 'fathom' is 6 feet - the amount of rope a man could measure with outspread arms; the 'knot' is still universally used as a velocity measure. In the farming world, a 'bushel' is still as convenient basket measure as the 'rod' is for fencing.
Up here in Canada, we had the metric system forced on us for purely political reasons; people have resisted these political forces amazingly well. To this day, after 25 years of metric indoctrination, ask any high school kid what he weighs and how tall he is and he'll answer: 175 pounds and 5 foot ten.
All measurement systems are arbitrary, even the Metric System. There is nothing special about the number 10 except that most of us happen to have 10 digits on our hands. I like what I learned as a kid(metric was for Maths & Physics classes, Imperial/SAE was for real life).

"Anything that existed before you were born is correct and a natural part of the world. Anything that appears before you are 30 is new and interesting (you could probably get a career in it). Anything that appears after you turn 30 is against the natural order of things." Douglas Adams (from The Salmon of Doubt).

 

For the scientist or engineer the CALCULATION of various things is easier with the Metric system but other than that, the English system is easier to deal with for the reasons given in the last several posts.

Have a great day,
Doc

 

There is no equivalent SAE grade for metric class 12.9. Grade 8 is roughly equivalent to class 10.9, but a 10.9 bolt is slightly stronger. There is also a metric class 9.8, which Ford used fairly extensively on suspension fasteners.

 

Actually, the metric system is not as arbitrary as you might think. I forget the connection, but it all has to do with the weight and volume of pure water at sea level. That way, you can calibrate metric instrument anywhere simply with pure water. The other problem with SAE as we use it is the fractions. I may be a math dummy, but I can add, subtract, multiply, and divide whole integers a lot easier than fractions. In my field as a toolmaker, we don't use fractions; everything is in thousands of an inch, so 1/8" would be expressed .125". Which is decimal, kinda like...metric! I'll admit, I use different 'body measures' all the time for roughly guessing the size of things.

 

I voted for SAE, not that they are "better", they are what I used growing up and can tell the wrench size by looking.

 

SAE the hardware store has a great selection,

 

I can't believe this is a tie (at this time)! I know the rest of the world uses the metric system, so being a U.S. citizen that is what it is to me FORIEGN.....GO SAE ALL THE WAY!!!!!!!!

 

Not quite true we (UK) use both. Many countries use both its just that metric has become the government approved measure but all our road signs are in miles, not kilometers as an example....

 

Hee-Hee-Hee-Snicker...

I pushed it over 50% for metric...

In all truth, there is no "better" here. Both have their uses. Given the choice, I'll use metric simply because my metric tools are in newer condition due to lower usage. All I REALLY care about is that ALL of the fasteners in a barticular project are the same type. Unfortunately, most of the newer vehicles and equipment I've dealt with over the past decade or so seem to be a bit mixed. (Probably has something to do with the simple fact that nothing much is manufactured completely in one place anymore...)