I don't get it, why is metric better?

So the argument gos on and on, metric or imperial, which is better?

More and more I have been paying attention to metric measurements and wonder how it is better. It appears to have some short comings.

I first started seeing this on full extension slide schematics. Almost all hole locations are on fractions of a mm.

For example hole locations are located a distant of 4.4mm, 4.6 mm, 6.4 mm, 34.3mm and so on. And then the width of the whole thing is 1/2".

Could those holes not be at 4,6,or 34mm??? Why the fractions of a mm. Can you actually measure or see markings on a rule that are at 10ths of a mm? FWIW a tenth of a mm is slightly under 4 thousands of an inch. There would be 100 marks in a centimeter.

Now you might say that is an odd case but take Leigh Jigs DT instructions to upgrade. Drill hole at 4.37mm, WHAT? And drill the hole diameter at 3.57mm. Seriously, has any one ever seen a drill diameter of 3.57mm?

And then there are threaded inserts to accept 5/16" coarse thread bolts. Drill pilot hole with 11mm diameter bit. In so much that you want to work with imperial sized bolts, couldn't they have just said drill pilot hole at 7/16"?

Reply to
Leon
Loading thread data ...

Leon wrote in news:f-ydnasS4tGHnzjKnZ2dnUU7- snipped-for-privacy@giganews.com:

This argument usually appears from people who are confused about the difference between metric/imperial and the difference between decimal/fractional.

There is no "better" between decimal and fractional. Which to use depends on the task at hand. The way nature works it is often convenient to divide things by halves. But when great precision is needed, decimal is clearly the way to go.

As for the actual metric/imperial question, clearly imperial is better, since it's units are based on the physical world, not on abstract reasoning that gives inconveniently proportioned units.

Along those lines, I am always amused by people who point out the sequence of metric subdivisions by 10, apparently totally unware that almost none of them are used. Take length - the two metric units of length are mm and km. Very rarely will you find something in meters (it's more likely to be 1000mm), even more rarely will you find something in cm. The same applies the other metric units, one or two prefixs will be used, and the remainder totally ignored.

(and don't get me started on the mangled mixture of metric and imperial units used in China...)

John

Reply to
John McCoy

Those fractions are probably due to conversion from Imperial Measure. I've seen analogous measurements in cookbooks for the US market where they have obviously converted metric to imperial weights and measurements. For example, I've seen a recipe asking for 1.76oz instead of the original 50g. Honestly, metric is MUCH easier if you work in it from scratch. Graham

Reply to
graham

Really? The foot used to be just that - the length of one's foot - until it was standardised.Graham

Reply to
graham

...

Well, not hardly...we're just getting started with one where there'll be

100, 200, 400, 800 m events just to name only a few... :)

While not totally ubiquitous, certainly the other units are reasonably common in every-day usage; it's scientific and to a lesser degree, engineering where the "power of 3" rule is prevalent, not everyday use.

Reply to
dpb

On 08/05/2016 4:16 PM, Leon wrote: ...

3.57/25.4*64 = 8.99528... or, going backwards, 9/64*25.4 = 3.57187500...

It's just some idiot converting their original design documents from imperial to write them in metric to make them "acceptable" for the EU rules to be able to export product w/o having duplicate documentation.

It's much cheaper to reprint the datasheets and leave the product unchanged than retool to the nominal nearest whole mm so they do the former rather than the latter.

Likewise the 4.37 mm is 11/64" -- 11/64*25.4 = 4.365625000...

(Although I'm sure you knew this, "just venting"...)

Reply to
dpb

Leon wrote in news:f-ydnasS4tGHnzjKnZ2dnUU7- snipped-for-privacy@giganews.com:

That's because they were made to Imperial dimensions which were then converted to metric. Hardware made to metric dimensions isn't like that.

LIke I said... made to Imperial dimensions.

No, of course not. But 4.37 mm is 11/64", 3.57 mm is just about exactly 9/64" -- and both are the result of some idiot making something in Imperial dimensions, then converting the dimensions to metric.

Why didn't they just make it metric in the first place??

Reply to
Doug Miller

On 08/05/2016 6:26 PM, Doug Miller wrote: ...

...

'Cuz it was already made and it's much cheaper to markup and print new materials to satisfy the mommy-state of the EU than retool...

Reply to
dpb

3.57mm = 9/64". Such odd numbers show up because the original design of the hardware was done in imperial not metric. If you are using truly metric hardware you will find nice numbers like 5mm a lot but never a fraction in my experience.
Reply to
John McGaw

On 08/05/2016 5:37 PM, dpb wrote: ...

And I suppose there's probably some EU regulation that requires them to be precise to some level such that rounding to 4 is outside of allowable tolerances as if 1/64" is going to make a hill of beans in the screw location; you'll be lucky to keep it within that owing to grain unless it's a fully automated production system that pays no attention to such niceties by being full CNC-controlled or the like in a production facility. By hand, it's in the noise...

Or, if may just be as noted first, just gave the job to some flunky to compute the numbers and plug 'em in and nobody ever gave it a thought as to whether it made any sense or not...you can see the same insanity in the spec's for almost everything that is an existing product or made to match up in building trades to the common use of feet-inches in layout such as the 16" OC stud spacing leads to 4x8 ply and then the nominal thicknesses for it and on and on and on. It'd one-up the Caterpillar in Wonderland for riddles...

Reply to
dpb

That would be a logical explanation but they the Leigh Jig and the slides are manufactured in a metric country and the slide have measurements that are clearly even number mm's and are made to the 35mm system. And the measuring of the holes on the slides don't really need to be any specific measurement at all.

Reply to
Leon

I think yo may have hit the nail on the head there. ;~)

Reply to
Leon

As already mentioned, that is a bastardized imperial translation. I've been working with metric machines using metric tooling to make usually metric dimensioned parts. It is rare to ever see a decimal and it is always .5 on some small items.

Many people here bitch about having to use metric, but on the occasion we give Imperial measurements of parts for tooling made in China, they have no problem translating. Once you use it for a couple of week it is really easy. You never have to wonder if you need a 23/64 or 3/8 wrench.

Reply to
Ed Pawlowski

And while that sounds like a reasonable explanations there are some metric standard measurements on the slides that are a common metric standard. These slides are designed to be used with the 35mm system and does have some dimensions in whole mm's. But then there is a measurement that is 4.6mm (.18in.) Maybe they got converted back and forth so many times common measurements of either have become skewed because of rounding.

Yes but 4.6mm converts to .18" that is a little less than 3/16"

I think it was made to one standard and probably converted back and forth too many times with the previous results.

Reply to
Leon

Actually 3.57mm rounds down to 9/64. If you want the accuracy to be that fine of resolution why not use easier to measure units. 1/8" would have been fine instead of 9/64" If the hole spacing/placement needs to be that fine they should specify what size screw to use in the hole also as a smaller screw will allow movement. But hole spacing is not "that" critical in this instance.

Reply to
Leon

It depends on when it was made. Graham

Reply to
graham

The strange thing about oil companies is that in most of their international operations, drilling is in metres but in the US it is in feet. The situation in South America is weird. Although the countries have long been metric, they still drill in feet. Graham

Reply to
graham

Actually I believe the biggest problem with the metric system is that meter is used in every instance of resolution. Micrometer, millimeter, centimeter, decimeter, meter , kilometer.....

How often do you suppose Bob yells, cut that piece of cable to 10 centimeters and it gets cut at 10 millimeters or decimeters?

Now one might suggest that they do away with any resolution more coarse than millimeters to cut down on confusion. Bob yells, cut that piece of cable to 19,800 mm's and I also need 4 cut at 1,980 mm's.

Remember the space craft that crash into one of the moons/planets several years ago? It was blamed on a conversion error. I bet their calculation from "x" miles to "x" kilometers ended up being converted to "x" meters. :~)

Reply to
Leon

October 14, 2014. ;~) Does that shed more light? LOL

Reply to
Leon

So are you saying that the metric system is like not being able to use all of the letters of the alphabet to spell all of the words? LOL

I realize that metric is just as easy to use as imperial but I can see how there can be some confusion if you are measuring a large difference in values. It seems to me that if all resolutions of metric measurements did not all have the suffix that they would be easier to differentiate.

Working with Festool tools you learn quickly to measure and convert between metric and imperial. There I said it, Festool! Get your points while they are hot! LOL ;~)

Reply to
Leon

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.