Metric...or SAE?

SAE… mainly because most of the tools I have are fractional which I purchased long ago. What really bugs me are vehicles that use both.

Hardware stores don’t have as much call for metric as you might think since normally techs do not use hardware fasteners on vehicles.

because he is in the machining business. he machines thing to fit inside other things. if (God forbid) we go metric, he would have to convert inches, to mm’s. 0.0001 = 0.00254. writing down 4 zeros and a one, is a heck of a lot easier to remember than 3 zeros, a 2, a 5, and a 4. thats 3 different numbers to mess up.

Trying to convert by force would bankrupt many industries.

I really doubt that.

We had these discussions and did some preliminary cost analysis in the '80s when I was in industry. We were designing and manufacturing commercial products to our own proprietary designs. It would have costs us a fortune and reaped no benefits.

Metric clearly has its place, particularly with product destined for the global marketplace, but SAE has a place in the world also. We still fly B52’s, still drive '57 Chevy’s, and still use kitchen sinks and commodes. Parts for the first two still need to be produced in SAE, and the second two would reap no benefit from redesign.

A box filled with both is helpful, if you’re doing aircraft and auto repair, so to me, it really doesn’t matter. But I have a question: does the standard bolt carry the same thread pattern (ie. 1/4-28) as it’s metric counterpart? All these years and I’ve never actually checked. But it does seem that a metric bolt has a larger tolorance than a standard, when installing it.

If hardware stores “chuck” SAE tools, who will the construction companies buy their tools from?

Hardware stores cater to the construction trade and to DIY home projects…that use construction materials. That entire industry is “standard”. 1/4" drills, 3/8" drills, 2x4s in 6’, 8’, 10’, 12’, 1nd 16’ lengths, siding with 5" reveal, 1x6" boards, 2" pipe, 10" circle saws, 12" circle saws, and on and on and on. You’ll find very little in a hardware store in metric…and yet they stock tens of thousands of items.

Now THAT is awesome! I’d love to know the conversion formula!

Metric Bolts And Their Thread Pitches Are Given In Sizes Like 8 x 1.25

.38, .357, .45, and 9 mm are Volkswagen specialty tools :slight_smile:

SAE vs metric is really a dead argument when it comes to automobiles. Practically everything is metric on anything built in the early 90’s or newer. I don’t even keep SAE tools on my cart except for 3 wrenches, 5/32, 7/16 and 1/2. Everything else SAE stays in my box until that rare occasion when I need it.

To avoid duplication, I have been buying all metric tools and retaing those SAE that aren’t duplicated: 3/16, 7/32, 1/4, 3/8, 1". Note that below 1", you only need a few smaller (less costly) sizes. If you keep SAE and supplement with metric, there are a greater number and larger sizes you must buy: 20/17/15/12/10 etc. Interchangeabe sizes measure 97 to 99% of the size. Most metrics are a skosh larger than SAE; but 19 mm is the other way and you might need a 3/4 for a lug nut on occasion. I just bot an SAE screw where I needed a metric (since the hardware store didn’t have the metric) and cut metric threads on the end of it with my metric only tap/dye set. I keep a conversion chart I made on my toolbox, so if someone needs a 5/8 socket, they get a 16 mm from me. So my take is that you don’t need 2 complete sets, just get metric and supplement it with SAE as needed.

I loathe & despise SAE!

Has anyone ever found a use for a 19/32 wrench or socket? Every tool set I ever bought had one or the other or both.

Why do you people insist on using the term SAE to mean inch? It doesn’t! SAE (The Society of Automotive Engineers) switched to metric back in the '70s when the automotive industry did. Thus SAE is more metric than inch as that is what they specify today, in the 21-st century.

Today there is only SAE metric in the auto industry. You people really need to update your information.

The SAE wishes people would not refer to inch fasteners as SAE fasteners (or wrenches). Both ASTM and SAE have specs for both inch and metric fasteners. SAE generally uses either the word inch or metric in the title to distinguish. (Most of the inch specs are in the aerospace arm of SAE and the reference number usually begins with AS.)

Metric is by far a lot easier to work with…but it doesn’t really matter when working on cars. What does it matter if the bolt is 1/2" or 12mm??

Where metric shines is when you have a 7/8" bolt and you need something twice as big…If you have a 19mm bolt…figuring out twice the size is simple…but really how often do you need to do that???

The biggest issue is the fear of conversion. I blame the school system for that. I absolutely hated all those math exercises converting english to metric. I.e. how many decimeters is a line that is 7.981 inches long, to the third decimal place. All these exercises did was scare children away from the metric system. If you want to know the answer, look at a ruler for heavens sake.

Take away the conversions and have kids use one system for awhile, reading inch rulers, Fahrenheit thermometers, cups and quart jars. Then spend some time with the metric system. No mixing, no conversions. I think you know where the kids will gravitate.

If the government was really serious about the US going metric, it would start making everything it works with metric. Speed limits would be kph. All government purchases on new contracts would specify metric dimensioning and fastening. SAE would be gone in no time.

BTW, machine shops that do precision work often use the measurements decimil and centimil. That is 0.1 mm and 0.01mm or about 0.004" and .0004"

"Now the only people besides those in the medical field who use the metric system are drug dealers (a kilo of coke)… "

Not so true… as far as I know you can still buy a 1/4 oz. of marijuana. Maybe it depends on the drug…

Re. SAE vs. metric measurements: I expect that eventually SAE will be phased out completely in the next decade or two, but there will still be enough older stuff out there that you will need SAE tools for the foreseeable future. Personally, it doesn’t bother me—if one won’t fit then I find one that will.

Why not use both metric and SAE? There are vehicles out there that have SAE bolts that will be around for decades to come. The same can be said for collector vehicles with metric bolts. By the way, countryroad32, a 19/32 socket or wrench works well on rounded 5/8" bolts. A rounded metric bolt can be removed with a SAE socket or vise versa. Think out of the box. They are just “tools” and a tool just helps get the job done.

'Why do you people insist on using the term SAE to mean inch? It doesn’t! SAE (The Society of Automotive Engineers) switched to metric back in the '70s when the automotive industry did. Thus SAE is more metric than inch as that is what they specify today, in the 21-st century. ’

Well, if you really want to pick nits, it’s not “metric” either. There are ISO and JIS bolts and they are not compatible even though they are both use metric dimensions.

B.L.E., the answer is simple. The term SAE is a misnomer just like calling an engine a motor. Go to any store that sells new socket sets and they are usually stamped SAE right on the package. I have a new socket set and it’s stamped SAE and Metric right on the plastic case. Americans have a really hard time letting go of terminology that’s ingrained in our language. SAE might go away in the 22cd century but I wouldn’t bet on it.