Boeing and metrcication question

Your drill indexes and wall charts do not list decimal sizes?

The three indexes in my tool box, all have the decimal equivalent on them. The wall chart I use most, has a list of all the "normal" drills in decimal inch, as well as decimal mm from smallest to largest, showing the sequence of sizes, of normally stocked drills in the 4 systems that we use (number, letter fraction, metric).

I am pretty sure we could shitcan the whole thing, if we just stocked the metric sizes in tenths all the way up to, say 25mm, but there would be a lot that never got used, eh!

Cheers Trevor Jones

Reply to
Trevor Jones
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You should explain your theories on metrication to the folks at the GM plant and see how it fits in.

There's lots of room in the human brain for learning a new thing or two. Like it or not, metric is all around you.

It's the great thing about standards! There are so many to choose from! :-)

Just another standard.

Cheers Trevor Jones

Reply to
Trevor Jones

SWMBO is currently baby sitting 3 grand daughters in the other London, having one hell of a time trying to cook in metric. She has been ignoring the metric system here in the dominion in the hope that it will go away. She says they don't have measuring cups or spoons or anything useful to work with there! Even the ovens are all wrong and she burns things. Gerry :-)} London, Canada

Reply to
Gerald Miller

Metric, which is fine with me, but also first-angle orthographic projection (as opposed to North American 3rd angle projection), which I really don't like.

They also will happily make stuff with Imperial fasteners, NPT fittings etc. if export markets demand it and pay enough for it to be worthwhile.

This seems like a non-issue to me. Any modern 3D modelling system works in internal units than can be switched to whichever system you like (including dual units) without changing the underlying model. I am designing some systems for aircraft, and we use a mix of mm and inches, usually kg for mass, usually Imperial fasteners (because they're cheaper and more available), but it's not really much of an issue in this corner of the real world. Getting used to GD&T seems like more of a hassle.

Best regards, Spehro Pefhany

Reply to
Spehro Pefhany

Thanks Trevor, I have all the charts and indexes. Since a 64th is approximately 15 thou why don't we simply label drills in increments of either ten thousandths or

15 thousandths. It would eliminate all of the charts.

Ivan Vegvary

Reply to
Ivan Vegvary

We could, and then we would need charts and indexes that told us which one was the one that matched up with the required hole size, esp when dealing with legacy standards. That would also leave out a pile of sizes that would not fit nicely into the spacing, sorta like why we have number and letter sizes, instead of just 64ths or 128ths fractional sets.

Making a law that "Thou sall be Metric henceforth!!) did not change any of the stuff that was already in place. Houses built to inch dimensions will be around for a while yet. The land survey of Canada (at least the prairies) is laid out in neat 1 mile by 2 mile grids. Etcetera, etcetera, ad nauseum. (my latin for the day!:-))

Canada tried that. Metric by decree. Then they found that, in order to be of any use at all, civil engineers, for example, had to be able to read the drawings that were done 100 or so years back, and make sense of them, so they started teaching both systems again. I can buy a yardstick, if I want to!!

If I get the ghist of it right, that was the intent of the metric system in the first place, to reduce the number of systems in use. It just added another.

Cheers Trevor Jones

Reply to
Trevor Jones

Tradition and tolerance buildup.

Reply to
Jim Stewart

Ivan Vegvary wrote: . Why don't they simply

Mostly, they do. All of my drill index boxes have the decimal inch size listed right by the size "designator". I have number, letter and fraction series drills, but the fractions are basically just another "size designator", like #43, or letter M. I work by the decimal inch size.

Jon

Reply to
Jon Elson

I wish someone would tell the Big Three to make up their minds.

I need both standard and metric to work on just about any car made after 1985

Gunner

Reply to
Gunner Asch

Brilliant copy protection! :-)))

You need a reality-update!

Nick

Reply to
Nick Mueller

the intent was to base the systems on interrelated values rather than arbitrary values with conversion factors between them.

a litre of water is a thousand cc's and weighs a kilo.

as opposed to 23 and a half kilderkirkins weighing 2 cwt 56 lbs 31 ounces in king james footric measures. :-) ....sorta thing

I do most of my work with a vernier marked out in mm and in 128ths of an inch. it is wonderful and direct. whichever system gives me fractionless numbers gets the nod.

Stealth Pilot

Reply to
Stealth Pilot

Yeah.

Another case of legacy, biting a manufacturer in the ass. The tooling on the line is still working, so they keep pounding out parts at the subcontractor level, and they keep getting installed at the assembly plant.

GM has been using metric bolts in their trannys since when, mid seventies? IIRC their trannies went all metric, quite a while before the rest of the chassis did.

The Brit bike industry went through a similar mish-mash approach, when they went Unified in the late 60's. Lots of Whitworth and Ba threads showing up on them well into the last days of their industry.

I do know that a friend of mine called me in the wee hours of the morning, swearing, as he needed a 17mm socket to reach the flywheel bolts on his GM truck. He also, was a metric holdout. He's starting to see the necessity, though he does not like it.

Digital measuring tools make it a push of the button to check the dimension to see where it fits into the scheme best.

Cheers Trevor Jones

Reply to
Trevor Jones

How do you get "fractionless numbers" in inch, when your vernier is marked in fractions? I don't get it.

As for the arbitrary units, I don't know of any that actually involve conversions in practical use. The units in practical use generally have whole-number relationships.

And beyond the largely illusory advantages of metrics in dimensional measurement, the supposed advantages of metrics' "interrelatedness" break down. Units of force, for example: the Newton equals roughly 0.101 972 kilograms of force (kgf). The cussedness of natural phenomena (defining a unit in terms of acceleration, for example, when its common use is as a measure of force) gets in the way of numerical elegance. Note the "roughly." Also note the lengthy decimal. There are many other such examples.

I'm not suggesting that the metric system is in any way "inferior." I'm just pointing out that its supposed advantages are vastly overblown.

-- Ed Huntress

Reply to
Ed Huntress

There is no such thing as "kgf". Outdated since decades and no longer "legal".

It's no wonder. The gramm is a unit of mass. Period. Never was different. It certainly is inelegant when used as force. The only thing getting in the way is an unknowing user. :-))

Nick

Reply to
Nick Mueller

Pffft. That wasn't the point. The micron isn't "legal," under the SI either, but everybody uses it, because "micrometer" can be ambiguous, since it's also the name of an instrument. Neither are the calorie, torr, gauss, maxwell, or oersted "legal," but they're all widely used in different sciences.

The point is that the standard units don't necessarily relate *in whole numbers* to the things we actually measure. Trying to be neat and tidy, metrics sometimes shoots itself in its own foot.

Nonsense. The Newton is defined in terms of kilograms, as well. It's just that it's defined in terms of acceleration rather than as force itself.

You sound like one of those pro-metrics folks who make up all of this supposed neatness of the metric system, Nick, and then wonder how everyone else doesn't agree with you. Those of us who don't agree with you are the ones who actually have used those units. They aren't all that neat.

-- Ed Huntress

Reply to
Ed Huntress

The "problem" is the acceleration on earth (depending on *where* you measure it). It is 9.81m/s^2. Thus the factor of 0.1... to "convert" (it is *no* conversion) mass to force. F = m * a

Maybe you find a planet where a = 10 m/s^2. :-)

You didn't understand the SI-system. It is based on **as** **few** **as**

**possible** units, the rest is derived/partially defined by them. They are: kg, s, K

I don't wonder of anybody who doesn't agree but at the same time doesn't understand the difference between mass and force.

I only have to look at the domain-dependant units of pound, pondal, pound force and whatever to see what mess it is.

Read about the SI-system before you talk about it.

Nick

Reply to
Nick Mueller

There probably is no such planet, which makes my point. The natural world and natural phenomena do not succumb to attempts to make "rationalized" multi-dimensional systems of measurement, most particularly systems that try to build everything from a minimum (seven, in the case of the SI) number of base units, which are themselves derived from only three fundamental units.

It works great in theory and doubtless it's an aid to many scientists working in many fields. For others, including the field of medicine, where I've been writing for the past few years, it simply results in a lot of clumsy derived units. Thus, you'll see older CGS units mixed with SI units in many fields, as a simple matter of practicality.

Yes, from which the base units of the metre, the kilogram, the second, the ampere, the kelvin, the mole, and the candela are defined. And then dozens of other units are derived.

It's a theoretically elegent system. By using those base units, the SI committee has developed a system that is theoretically coherent and conceptually minimalist, but which also forces you to keep things in your head that are far abstracted from what you're actually measuring, or to memorize the system without thought -- which obviates any "rational" advantage the system may have, in much practical use.

Again, we're not arguing over the advantages of the SI system to a scientist performing elaborate calculations about celestial bodies and their photometric properties, or remotely measuring their mass and angular velocity. We're talking about the everyday measurements that make up the vast majority of numerical evaluations made by people in the world. For them, defining the unit of force in terms of acceleration, when they're interested in how big they'll have to make a support to keep a cistern off the ground, forces them to use (if they're using SI units), abstractions that they'll have to memorize or convert roughly into something sensible -- the weight of that cistern when it's full of water. They're forced to use Newtons, when what they're dealing with is kilograms of force, or pounds, if they're so inclined.

I understand it quite well, thank you very much. The traditional units of force have been defined quite precisely in terms that are perfectly acceptable to the stickiest proponent of the SI. The latter just don't like those derived units. They're inelegant. They're also very useful.

I don't know anyone who uses pondals, and the pound, both as a unit of force and as a unit of mass, is quite handy within its domain.

I am not domain-independent. I am not trying to write the General Theory of Relativity. Neither are you, and neither is (almost) anyone else.

You really can be annoying at times, Nick. It's very unlikely that you've read as much about the SI system as I have, unless you spent more than a year, as I did, outlining a book on quality assurance.

-- Ed Huntress

Reply to
Ed Huntress

I'm with you Ned, I can convert at will and it does not bother me. But my question has yet to be answered by anybody in this long and interesting thread.

Has Boeing gone metric? Not only in machined details, but basic design critera as to load, power, thrust, weight, HP requirements, fuel consumption, etc. For example... are hydraulic systems now labeled in Newtons or still in lbs/sq/in?

Because nobody in the US, nor repair centers around the world know what the heck a Newton is on a machine label. They sure understand HP and PSI.

Wayne

Reply to
Wayne Lundberg

Thank you one and all for your insight and thoughts. But my question remains unanswered.

Has Boeing gone metric in their basic aircraft design world of HP, thrust, Lbs/sq/in, drag, coef friction, tensil strengths, elongation, stress, strain, materials, heat treatment parameters in f, times in minutes, miles and not meters.... wire gauges, fasteners and on and on an on which made them the greatest manufacturer of quality aircraft in the world?

Please. I'm not bashing the metric system. Just plain curious as to why anybody would discard a century of technology simply to satisfy some imaginary concept that just because the rest of the world jumps off a cliff, why should we?

Lemmings?

Reply to
Wayne Lundberg

Ed:- I will be using Imperial measure until I die. Damnit, I will use Whitworth and BSF threads in preference to others until I no longer have the capability to make them. But.. The SI system holds together far better than the Imperial system for anything that involves any form of calculation. I have no problem with a 1 hp motor, but going from there to 550ftlb/S and 2,545Btu/hr as opposed to a 1kW motor being 1000Nm/S and 1000J/S brings it home that the SI system is _rational_

Other derived units:- 1F=1V/C=1Vs/A What's a Jar worth?

1Tesla=1W/m^2=1Vs/m^2 , I don't even know if there is an Imperial unit of magnetic flux density!

The conversion factor between base and derived units is always 1, PI or E. That really helps when checking a calculation for consistency. You _can_ do the same with fps units, but only if you stick to base units. This isn't abstract science, this is everyday engineering, Things like calculating the impedance of a length of power line, or the size of the flywheel needed on a press.

Mark Rand RTFM

Reply to
Mark Rand

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