Why People Prefer Imperial to Metric

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10 Wheeler Rob
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Re: Why People Prefer Imperial to Metric

Post by 10 Wheeler Rob »

Metric dose not make pipe sizes and the piping components. Standard fasteners in metric are typically lower strength materials. Kilograms is not a force, it is a mass, Newtown and dynes are force, pressures are pascals. Once you get away from size measurments it still reguires a lot of conversions to deal with.

And drawings do not call out the tread pitch for "ordinary" pitch treads, your Just supposed to know what it is.

Just my $ 0.02 worth, I had to deal with all kinds of conversions in engineering in every system!

Rob
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rudd
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Re: Why People Prefer Imperial to Metric

Post by rudd »

Harold,
I was not intending to infer that one system is inherently more accurate. Just that one system is easier to divide up into a common smaller unit from the larger unit, and was the traditional set of measurements for some trades long ago.

I would like to make one more comment on metric "standards". While on a mountain road outside Cripple Creek Co. I came across a disabled volkswagen with a couple older ladies in it. Maybe 2-3 people might have used that road per day. Stopped, had a look - it had lost a couple nuts that hold the carb to the intake. Yes, this was a while back. I was driving a Japanese car, and was able to "borrow" a couple nuts off the trim on my bumper - they fit the carb studs fine, same size/thread. Car cranked up, they were able to make it back to civilization.

However, the VW nuts used a 12 mm wrench, same size bolt/nut on my car was 13mm. I understand this is common between European metric and Japanese metric.

What does "torque me off" - My Ford pickup uses a mix of Imperial and Metric fasteners. I kept the little Japanese car for 300K miles, rebuilt the engine and trans myself. Car got rear-ended and totaled right after the rebuild, so I got another body and put all my reworked mechanicals in it. I'm no stranger to metric, it's fine. Imperial is fine. But don't make me drag two complete sets of tools out to the truck to change the brake pads!
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WesHowe
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Re: Why People Prefer Imperial to Metric

Post by WesHowe »

Metric has been a legal standard in the U.S. for a long time. Everything you buy has the weight/volume listed in both Imperial and Metric. BUT... (almost) everything you buy, excluding beverages, is in an even or round fractional Imperial unit (pint, half-gallon, 1/4 pounder).

So part of this was expressed earlier, we are used to and can easily envision how much liquid a quart is. I know a liter is 3+ ounces more, which brings to mind what is, as I see it, the core reason why the U.S. is not on metric. All the common even or even-fractional metric weight/volume units (not linear distance ones) are larger than a similar-sized imperial unit.

A half-gallon is smaller than 2 liters. A pound of hamburger is less than a half-kilogram. And so on. The first manufacturer to convert from even-imperial to even-metric has the handicap of raising his price to compensate for the larger commodity input requirements. Even a good comparison shopper would be less likely to buy a higher priced package for no other reason than it was more of whatever than they needed to buy.

The beverage manufacturers went to liter sized bottles long ago, when they used the opportunity to forgo a price decrease by offering "free ounces" in larger (liter sized) bottles. So far I have not seen any other companies find a competitive advantage to conversion.

I have become accustomed to liter sized beverage containers over the years since they were introduced, and don't doubt that I would also adjust to other changes, in spite of my steadily advancing age and with it increasing resistance to change. But I don't see any impetus for the retooling required for the country to convert en masse, absent a mandate (unlikely politically) or a tax incentive (decreased tax revenues, again not likely).

We can muddle through the next 100 years of metric the same way we muddled through the last 100 years of it.
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Harold_V
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Re: Why People Prefer Imperial to Metric

Post by Harold_V »

rudd wrote:Harold,
I was not intending to infer that one system is inherently more accurate. Just that one system is easier to divide up into a common smaller unit from the larger unit, and was the traditional set of measurements for some trades long ago.
Understood! And, I agree. In my opinion, that's the real value in Metric. The negative, for me, is that I rarely have a concept of size when anything Metric is being discussed, but that's very unlike Imperial, at least for me.
What does "torque me off" - My Ford pickup uses a mix of Imperial and Metric fasteners.
Also understood!
I bought a new 1986 GMC 1 ton pickup. In '96, before I could leave Utah to drive to my new address in Washington, I had to replace the water pump. Imagine how thrilled I was do discover that there was a mixture of Metric (air conditioner) and Imperial (everything else).

We live in a world economy these days, so we most likely are going to have to settle for the status quo. I don't see the US changing, nor should they be required to do so. The Imperial system works for us, and has served us well for a long time. It's the devil I know, although I have prayed at the alter of Metric when required to do so. :-)

Harold
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10 Wheeler Rob
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Re: Why People Prefer Imperial to Metric

Post by 10 Wheeler Rob »

New China manufactured snow blower arived today. All the bolts for assembly were metric, which was expected. There was a smaller screw on the shute control that had a buggered thread. Much to my surprise it was a #10-32, and I had drawer of socket head cap screws for the replacment. Some times you get lucky.

I bought a 4X6 inch metal band saw few years back, Harbor Freight special. When I started assembling it I was pleased to see in the manual said the fastners were imperial threads, but when I grabed a wrench they didn't fit. Upon measurement the heads on the 1/4-20 were metric, I just laughed and laughed.

Rob
dly31
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Re: Why People Prefer Imperial to Metric

Post by dly31 »

When my boys and I first got dune buggy and Rabbit VW's we found that we could manage most fasteners with imperial tools except for the 10MM ones. Metric tools were not common here but we bought a 10MM socket and combination wrench. Later, we found a set of combination wrenches at K-Mart and bought them. To our surprise, the set consisted of every whole MM size from 8MM to 19MM except 10MM! It was if the set was specially made for someone who already had the most needed 10MM wrench.
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eeler1
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Re: Why People Prefer Imperial to Metric

Post by eeler1 »

thousandths of an inch is the perfect increment for machine work. Metric can do the same just as well, but looks funny to get the same dimension.
redneckalbertan
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Re: Why People Prefer Imperial to Metric

Post by redneckalbertan »

We've been using the metric system up here since the mid '70's... But a metric tape measure is harder to find than hen's teeth! They have combination tapes with sillymeters on one side and inches on the other, I find those tapes extremely frustrating... inevitably the system you need to measure with is on the wrong side of the tape! Lee Valley is the only store I have found that carry a metric only tape.
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steamin10
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Re: Why People Prefer Imperial to Metric

Post by steamin10 »

Working a job sight, I found a long tape that was a wind up 100 foot, in a brown case. Not paying much attention, I tossed it in my work box. Some time later, a co-worker needed a tape, to lay out a wall. when we came to build the wall studding, it was weird. Come to find out, it was an engineers tape, with feet and tenths. Ya know, 1-2-3-4-5-6-7-8-9 next foot. what a laugh that was.. NOT!

SAE threads were worked out by the strength of steel for the threads long ago. It was not by a convenient number, which is the reason that metric threads have problems in the strippage area. For along while, Japanese and English metric could not be used together, as the base manufacturing standards were different. Growing up riding Hondas with a buddy that had a BSA, and another a BMW, we went through the torture of finding the right fasteners, when needed.

Today, I can use metric bolts in my models, because they have much finer sizes with hex and socket heads than the SAE that have major gaps in the size jumps. Availability in assorted heads is a challenge, and I am held up on a project because of it. In that case, I may drill out the metric, and go SAE for the button heads as I have no patience chasing fasteners. I lost a bolt that locks down the ROPS bar on my Case diesel, that is a rebadged Mitsubishi compact. For two bolts and nuts, ordered through Fastenal, ( so I dont have to deal with one new and one crusty -rusty old one) bit me for $17 and change. :cry: Ouch! So I try to avoid that trap, and stay with most common fasteners.

EDIT: That goes for foot pounds, and newton meters too. I have no concept of a fig newton, by the meter of 39 inches, or whatever.
Big Dave, former Millwright, Electrician, Environmental conditioning, and back yard Fixxit guy. Now retired, persuing boats, trains, and broken relics.
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mcostello
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Re: Why People Prefer Imperial to Metric

Post by mcostello »

Flip over Your carpenters square. The scale is in 1/12's. Made several months of conveyor belts with it that way.
chuckey
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Re: Why People Prefer Imperial to Metric

Post by chuckey »

Metric threads strip easily because they are of the sharp 60 degree form, rather then the Whitworth 55 degree form with smooth tops and bottoms.
The only need for standard thread diameters is so you can get a length of stock 1/2" bar and put a 1/2" thread on it with a die. If it needs to be fitted to a plate, you reach for your .42?" drill, drill the tapping size hole and then tap it to the thread. Even if you want a running clearance you need to pick up a .505" drill for the hole. So exactly how much work is done today, putting threads on stock sized bars?, less then .01% of all threading work?
The modern metric system should have followed the BA threading convention, thread form like the Whitworth and each size thread a model ~10% smaller the next one. Just extend the series the other way, so it went 4, 3, 2, 1, 0, a, b, c,. . . .( https://en.wikipedia.org/wiki/British_A ... ew_threads )
A second series could be introduced, BAC coarse, pitch is 50% coarser.
On the more general metric argument, builder have gone metric here so the size of timber is in mm, so are room sizes. Builders and millimetres?, builders struggle with fractions of inches as their day to day tolerances.
Frank
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tornitore45
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Re: Why People Prefer Imperial to Metric

Post by tornitore45 »

Machining with the imperial system is done in decimal with 0.001" as the basic fine unit, designing is easy since relative distances are a simple difference.
However, in other fields, unnecessary complications arise with the imperial system.
Just one example:
Calculate a transformer. How many 32AWG turns per layer can fit on a bobbin 2 17/32 wide?
What is the average turn length knowing the bobbin is 1 5/32 x 7/8 and the stack up is 7/16?
Convert everything to 32nd, add, repeat for max turn length, average. Now calculate winding resistance: I have memorized the copper conductivity in ohms x meter-lenght/mm^2-crosssection but would be of no use to know the same as ohms x foot-length/circular-mils because the wire diameter in in AWG units. Unless you have tables you can't do anything. And this does not account for the magnetic design where Gauss, Tesla and Oersted are normalized to a metric areas.

I am equally comfortable to work in both system, most of the conversion factors are engraved in my head, but I rather avoid fractions with power of 2 and 3 factors, screws with numbers instead of diameters, drill bits with fractions letters and numbers and Gauges all different depending on what they gauge.
I like a 1/4 kg steak a bit more than a 1/2 pounder.
Mauro Gaetano
in Austin TX
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