Do you use imperial or metric in the shop.

[twistsol]

About 7 years ago, I converted my shop to metric mainly because I started using the 32mm system for building cabinets. Slowly, I started thinking of base cabinets less as a 24" deep cabinet is that is 608mm and now it's just as a 608 base. I'm starting now to find that I have to convert measurements to metric to visualize them.

I still use imperial for construction and now find it more difficult.

[LCHIEN]

Technically, its more correct to say I use USCS (united states customary system) or if you are fussy, old English units.

The USCS system had its roots in the old English system traced back to the Romans.

USCS was established and common in the 13 Colonies when they broke away and became independent in 1776.

Then Imperial system was established almost 50 years later in 1824 by decree of the British crown

USCS and the Imperial system share linear units of measure... feet, inches, yards, miles, but other stuff, although similarly named is somewhat different,
Because of the feet and inches and miles commonality a lot of people incorrectly conflate Imperial with USCS.
Or worse, because of mechanics tools packaging, they think we use SAE which is the Society of Automotive Engineers series for fractional inch fasteners standard sizes.

Metric has been in use only 123 years. Since 1898 when France designed it to solve 1 million separate measurements in use after the Revolution.
Imperial was used for 140 years. 1824 to 1965
USCS is going on 245 years.


Loring
Proud user of USCS units since 1952.

[atgcpaul]

At work, it's all metric, but in my shop, it's all imperial except on my Domino which has metric markings. All my measuring tools are in imperial and I'm not going to switch.

This country we're in can't seem to make up its mind. Liquid and weight measures at the gas station or grocery store are in pounds and gallons, but all length measurements at the hardware store and on the roads are metric.

[cwsmith]

Way back in 1973 I was told to use metric when writing all the new instruction manuals. I told my boss that wasn't going to go over too well, but that was the corporate orders. Sure enough, within just a few months it was stopped. A short time later (late 1974, as I recall), it was decided to put Imperial (what I referred to as "U.S. domestic") measurements with metric immediately following in parenthesis. That went on for awhile and some decided that the metric for air pressure being "kg/sq cm" wasn't preferred and we went to "bar" (French influenced I think). Finally, ISO pushed it to "kPa" (kiloPascals) and I believe air pressure measurements are still using "psi (kPa) today.

My boss at the time, used to think that everything was going to be a direct mathematical conversion and I recall a few discussions that things were always going to be rounded off, in an ISO-compliant country or business-anywhere, we simply will not make a pair of pants to the length of 812.8 mm (32 inches), so your pants are going to get a bit longer or shorter! Funny thing though was that in the air compressor division where I worked at the time, "metric" was pushed pretty hard for documents, yet in the shops we were still using Imperial measurements and so all drafting prints were just in Imperial as they had always been; and over in the other divisions it was just Imperial everywhere.

For a long time I thought it was going to be a struggle, but eventually Imperial would win. That was almost fifty years ago, I think a lot of companies have just stopped trying to convert to a single international standard and today many, if not most, of us are still measuring they did back in the first half or the 20th century.

Here in my little world, I at least know that the other measurements exist. I have both Metric and Imperial wrenches, sockets etc., as well as a few measuring devices. That said, most of the measuring devices that I use in the shop being steel tapes and various metal rulers, are Imperial. I do have two, foot-long rulers I used on the drawing board that provide fractions and 50th inch markings, but no metric.

I guess I'm just 'old school',

CWS

[capncarl]

I kinda like the measurement system the weather reporter uses on TV.... 10ths, so much easier to translate to metric and fractional. Bullpoo!
I really wish we had changed from fractional to metric when our brains were still young and unmyred by learning fractions!

[mpc]

I was introduced to the metric system in elementary school (back in the 1970's) but it never became dominant in school or elsewhere. I remember seeing highway "distance to WhateverTown" signs with both miles and kilometers, and some speed limit signs included KPH but that's about the only times I remember seeing metric used in America outside of school. It was commonly used in engineering classes in college, along with foot/pound/slugs units... my Aero engineering classes used both systems. Metric was almost nowhere to be found once I graduated. The only time I see it these days is a) emails with a US friend who is a staunch metric supporter, and b) on the inner scale of my older car speedometers - they have both MPH and KPH scales.

I still have centimeter metal rules in my desk and one based inch rule with 4 scales: 16ths and 32nds one one face, 10ths and 100ths on the other face. In the workshop though there is nothing metric. The idea of tenths-of-an-inch makes a lot of sense to me, compared to 8ths, 16ths, 32nds, etc.

Mentally, I can easily use either inches, feet, miles, centimeters, millimeters, and kilometers for linear measurements - I'm reasonably fluent in any of them. But, when using those to compute area or volume (e.g. square feet, cubic inches, cubic centimeters)... I have a better "feel" with the US/Imperial units; I end up doing the math to convert cubic centimeters to cubic inches for example.

liquid volumes in metric? Not quite so fluent other than knowing 1 liter is just a bit more than 1 quart.

Metric mass & weight? I have a feel for what 1 pound is... but no real feel for what "1 kilogram" is without doing the math to convert it to pounds; for ballpark approximations I remember it is about 2.2 pounds per kilogram.

Metric forces? Nope, no real feel for what is "1 Newton of force" while I have a good feel for "1 pound of force."

Temperature? I think in terms of degF; anything in degC I mentally convert to degF first. What is a "hot" day in degF? ==> 80 plus. What is a hot day in degC? Gotta mentally do the math to get 26 plus. Normal human body temp = 98.6 degF requires no thought; I don't "know" the degC equivalent without first doing the math to get 37. For most of my engineering career neither degF nor degC were that important, degrees Rankine and degrees Kelvin ruled all. Those have the same degree step sizes as degF and degC but start at "absolute zero" temperature:
temp in Rankine = temp in Fahrenheit + 459.67 degF because "absolute zero" is -459.67 degF
temp in Kelvin = temp in Celsius + 273.15 degC because "absolute zero" is -273.15 degC

I did have one humorous encounter with metric years ago. A co-worker and I were carpooling to a company that built and sold "water tunnels" (similar to wind tunnels except they use water rather than air, that allows much smaller aircraft models to be used for study) as well as early desktop aircraft simulators (think early versions of Microsoft FlightSim with far more accurate aircraft modeling software). Since I had been there once before - and thus (sortof) knew how to get there, she decided I'd navigate while she drove. "In two miles, make a right turn" I said. She started laughing... "my car reads in kilometers. I bought it while I lived in Montreal!" "Okay, in just over 3 kilometers make a right turn." She laughed again, surprised I could convert in my head.

mpc

[leehljp]

Mentally, I can easily use either inches, feet, miles, centimeters, millimeters, and kilometers for linear measurements - I'm reasonably fluent in any of them. But, when using those to compute area or volume (e.g. square feet, cubic inches, cubic centimeters)... I have a better "feel" with the US/Imperial units; I end up doing the math to convert cubic centimeters to cubic inches for example.

That's ME exactly.

For weights: kilograms and pounds, not much of a problem either, but grams and ounces are beyond me.

I don't like weather wind speed (think typhoons) in "meters per second" as I heard overseas. KPH or MPH, I can deal with those!

I got introduced to metric in physics and chemistry in the early '60's and it stayed with me. It was a great advantage when I moved to Japan in '86. Moving back and forth for KPH/MPH, inches/feet-mm/meters wasn't difficult. The air pressure for air compressors was confusing.

Temperature wasn't a problem but an amusing thing happened when we were flying back from Japan on year: We landed in Chicago from Osaka, the pilot came on and said welcome to Chicago (O'Hare, I think) with the temperature at 30°. My then 12 year old daughter (who was 2 when we went to Japan) said "So what is that in real temperature dad?" . . . I said: That is -1° to you.


Do any of you remember the Canadian flight back in the 80's that ran out of fuel because there was a mixup in calculating the amount of fuel needed for the flight? There was a mix up in which they used pounds/liter instead of kg/liter. The result was a dead stick landing of a 767 on an abandoned airfield in which drag racing was taking place.

http://hawaii.hawaii.edu/math/Courses/Math100/Chapter1/Extra/CanFlt143.htm

or

https://en.wikipedia.org/wiki/Air_Canada_Flight_143

[LCHIEN]

I'm reasonably comfortable with working in linear measures, km, meters, cm, mm
and in weight/mass kg, metric tons, grams.
having worked with parts and handling them.
Units like pressure in kPa are hard to visualize, I know how to convert to PSI but don't have a feel for the size until I see it in PSI.
As an EE, we work with metric constantly (Volts, amps, watts, joules are all metric)
Its a matter if using it and being reminded all the time of how big things are.

[mpc]

Do any of you remember the Canadian flight back in the 80's that ran out of fuel because there was a mixup in calculating the amount of fuel needed for the flight? There was a mix up in which they used pounds/liter instead of kg/liter. The result was a dead stick landing of a 767 on an abandoned airfield in which drag racing was taking place.

http://hawaii.hawaii.edu/math/Courses/Math100/Chapter1/Extra/CanFlt143.htm

or

https://en.wikipedia.org/wiki/Air_Canada_Flight_143

NASA's Jet Propulsion Laboratory facility and Lockheed Martin Astronautics did a similar mistake causing the Mars Climate Orbiter spacecraft to burn up in the Mars atmosphere rather than enter orbit. LM used English units, JPL used SI/metric... and one term slipped past the conversion process.
LA Times article on MCO
SimScale company article on MCO with a funny cartoon and dunce caps

The second link also references the Gimli Glider incident and a few other measurement units screw-ups.

mpc

[atgcpaul]

All of our instruments in the lab are calibrated in metric in the X-Y-Z through their respective software. One company's software, though, uses centimeters as their units whereas all their competitors use millimeters and they don't readily display the units. It drives me nuts. If I need to jog it left by 0.5mm, I have to remember to divide by 10 or I will cause a crash.

[LCHIEN]

The real question is, if you are using inches, are you using fractional inches in binary fractions. e.g. multiples of 1/2. 1/4, 1/8, 1/16. 1/32 nd 1/64th inches or are you using decimal fractions i.e. 1.375" is 1 and 375/1000 inches, (AKA 1-3/8 inches in binary fractions).?

I find my self doing a mix.

Measuring tools in binary fractions (rulers) and decimal fractions (calipers)
Marking tools in binary and decimal
Computing and comparing on paper plans is often easier for arbitrary increments in decimal. but sometimes I design things in binary fractions because they are easy to set up (router bits, rabbets bits, setup bars, ) are all in binary fractions.

[Carlos]

Metric weights are easy for me, and indeed its my preferred way to cook and track nutrition. Much easier to measure 100g of peanut butter than 1/4 cup or whatever. For lengths, I do very well at small metric lengths, but it falls apart for me at larger numbers. So say 0-300mm is something I can envision, and 0 to a few KM works too. But larger numbers start to blur for me. I know what a meter is in inches but start to lose the larger numbers. 700mm is not a thing I can picture.

[cwsmith]

The real question is, if you are using inches, are you using fractional inches in binary fractions. e.g. multiples of 1/2. 1/4, 1/8, 1/16. 1/32 nd 1/64th inches or are you using decimal fractions i.e. 1.375" is 1 and 375/1000 inches, (AKA 1-3/8 inches in binary fractions).?

For me it's a mix, and if I'm sketching or drawing something for someone else, it depends on the audience. For woodworking it's generally fractions, as that is what most woodworking tools use. But of course everything woodworking is not fractions, so it's a mix as required.

CWS

[atgcpaul]

Not that I need it, but I feel like I need "2.54" tattooed on my arm. This morning a manufacturer in the UK sent me a shipping manifest for a new instrument, but with dimensions in centimeters. I know roughly how big our freight elevator is in feet, but I don't think in centimeters.

1451cm is a really long crate!