# who has gone metric?



## MCRIPPPer

just want to see how many guys in the U.S. work in metric. i am committed to metric. i only own metric taps and dies, only have metric screws, only use metric tools, all the machines like mill, lathe, car, motorcycle are naturally metric (although my mill has imperial lead screws.) unfortunately i have to buy end mills and drills in fractional because it is rare to find metric versions in the u.s. 

material is still fractional as well but it gets machined down anyway. 



so shout out if you are metric and shame on you if your not! :nono:   :lmao:


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## John Hasler

MCRIPPPer said:


> just want to see how many guys in the U.S. work in metric. i am committed to metric. i only own metric taps and dies, only have metric screws, only use metric tools, all the machines like mill, lathe, car, motorcycle are naturally metric (although my mill has imperial lead screws.) unfortunately i have to buy end mills and drills in fractional because it is rare to find metric versions in the u.s.
> 
> material is still fractional as well but it gets machined down anyway.
> 
> 
> 
> so shout out if you are metric and shame on you if your not! :nono:   :lmao:



I'm comfortable with both systems and I'd go metric if I could but 99% of my tools (mostly old junk) are customary.  If I was to win the lottery (not likely as I don't play it) perhaps I'd buy all new metric stuff.


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## uncle harry

MCRIPPPer said:


> just want to see how many guys in the U.S. work in metric. i am committed to metric. i only own metric taps and dies, only have metric screws, only use metric tools, all the machines like mill, lathe, car, motorcycle are naturally metric (although my mill has imperial lead screws.) unfortunately i have to buy end mills and drills in fractional because it is rare to find metric versions in the u.s.
> 
> material is still fractional as well but it gets machined down anyway.
> 
> 
> 
> so shout out if you are metric and shame on you if your not! :nono:   :lmao:



Well,...Most of my iron is old and Imperial including all of the meterology stuff ('cept for the occasional digital stuff) so I guess @ age 73 I'm not hell-bent to metrify. Most of our rough carpenters still use Imperial.


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## Hawkeye

I think I'm becoming bilingual enough that if I needed to make a metric part to fit something, I could. The iGaging DROs are switchable and the Swedish lathe has metric carriage dials. My vehicles are split between miles and kilometers, so I'm always thinking both ways anyway.

For projects, though, I'll stick to SAE.

And shame on you for trying to force your choice on me. :lmao: Seriously, though, it _is_ a choice, at least at the hobby level.

At work, the code book has metric tables, but you can't buy metric conduit here, so you have to translate.

Having said all that, metric math is a _lot_ easier.


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## John Hasler

uncle harry said:


> Well,...Most of my iron is old and Imperial including all of the meterology stuff ('cept for the occasional digital stuff) so I guess @ age 73 I'm not hell-bent to metrify. Most of our rough carpenters still use Imperial.



I think you mean US Customary, not Imperial.  The latter is what used to be used in the UK and is slightly different from the former, which is what is most commonly used here in Wisconsin.


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## jumps4

president Nixon had the right idea here in the US years ago but It never fully came about, instead we have to learn both systems, have both sets of tools and waste more time converting. Nasa crashes orbitors into mars because one company writes software in metric and the other in imperial.
metric is so easy compared to imperial all on a base of ten, not the length of some guys foot divided into 12 parts then divided by 16,32,64,1000,10,000 parts 
I wish it would have all converted but I still use the inch system most of the time
steve


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## MCRIPPPer

yea. im only 18 so im hoping its worth it to learn metric!  sooner or later the U.S. will switch for real just so we can interact with the rest of the world lol. 

my micrometer is imperial but a quick calculation will convert to metric. for example, i want to make a 10mm diameter on the lathe just put 10/25.4 in calculator =.3937



.3937 x 25.4 = 9.99998 mm. close enough to 10 for me!

so an imperial micrometer is just as accurate for measuring metric as imperial.


the best part about metric is you get rid of that nasty half digit on the digital calipers. Ha.




imagine a new world with no 127 tooth gears, no reversing your lathe to cut metric threads, your socket set would be 1/2 off and 1/2 times the weight! 2x more space in your tool box! one less button on caliper! you could even feel like your driving 1.6x faster! :lol:


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## samthedog

You have no idea the havoc it causes in international companies. We make equipment for the oil industry and our Houston designers use ASME and we use ISO 8015 for geometric tolerances. When comparing drawings or trying to run projects over the various sites, the incompatibility of these standards means a great deal of headache.

I grew up in the 80's in Australia where there was still a great deal of SAE. I am bilingual but for machining, I stick to metric.

Paul.


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## darkzero

I haven't, my machines are import & I do try to keep all fasteners metric on them as well as anytime I make something for them. That way I only need to keep a metric set of tools close by. I used to work on imports for automotive so most of my tools are metric anyway.

Most of my measuring tools can read in metric (DRO, calipers, micrometers, depth gauge, height gauge, etc.) but I still prefer to use American standard. Even when I have to machine a metric dimension, I still convert it American standard to make the cut. I do use metric sometimes but it's not what I prefer. I also hate threading metric on the lathe, can't use the halfnuts.

As you mentioned, metric endmills are not as common here in the US. Neither are drill bits. Along with fractional drills, I also use number drills & letter drills, are there similar metric equivalents to these? I have never seen any readily available.

I do agree the metric system makes more sense & I think is easier to use. But when it comes to machining & other things I just stick with American standard, since that's what's commonly used here it makes it easier. Like if you go to the hardware store & need to buy plumbing supplies or electrical, you don't go looking for pipes in metric sizes.


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## jumps4

In the us we have probably only used the 1000th of an inch for less that 100 years, machinists measured everything in fractions of and inch and most of our tools still reflect this, fractional drills reamers ect. so we really didn't even convert out tools to 1000's of an inch yet that's only been a hundred years.
steve


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## MCRIPPPer

i have to be good at inch pound system because it is used everywhere. at work i machine things in imperial because that's what everyone here uses, but at home, i get to use the lovely system that is SI.


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## xalky

I can work in both systems. The problem I have is that I was pretty much raised on Imperial measurements, so I think in those terms. 

If someone says to me that a part is 15 1/2" long and 1/2" diameter, I immediately know what that looks like in my mind.

Now, If someone said the part is 1550mm by 14mm diameter, it means almost nothing to me. I have to refer to a metric tape measure or something to visualize what that means.

I can look at an Imperial HEX HEAD bolt and know immediately what size wrench to grab to turn it- Again, that's not the case with most metric bolts. Over the years I've gotten better at "knowing" a metric bolt size by sight, It's taken years of doing to get even a fuzzy recognition.

I think the brain gets locked into thinking in certain terms at a fairly young age, probably early 20s at the latest. After that you become kind of locked into what you learned as a youngster. I'm 49 yrs old. I suspect that most guys my age are in the same boat. )


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## MCRIPPPer

jumps4 said:


> In the us we have probably only used the 1000th of an inch for less that 100 years, machinists measured everything in fractions of and inch and most of our tools still reflect this, fractional drills reamers ect. so we really didn't even convert out tools to 1000's of an inch yet that's only been a hundred years.
> steve




this really pisses me off. especially on the milling machine when i need to find the radius of an end mill for example. the tooling is fraction and mill is decimal inch! and most of the fractions dont turn into a friendly decimal.


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## Cobra

In this country we solidly on the fence!  Metric to drive or by flour, SAE to build houses, and both in machine and maintenance shops.  
Overall not a big deal to adjust as you need.  I think there is too much existing equipment and supplies to make a total change any time soon.


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## MCRIPPPer

actually the one thing i think will never change is carpentry. you will never see a 50x100 in the lumber store!

although 2x4 and 4x4 means nothing anyway.


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## darkzero

xalky said:


> I can work in both systems. The problem I have is that I was pretty much raised on Imperial measurements, so I think in those terms.
> 
> If someone says to me that a part is 15 1/2" long and 1/2" diameter, I immediately know what that looks like in my mind.
> 
> Now, If someone said the part is 1550mm by 14mm diameter, it means almost nothing to me. I have to refer to a metric tape measure or something to visualize what that means.
> 
> I can look at an Imperial HEX HEAD bolt and know immediately what size wrench to grab to turn it- Again, that's not the case with most metric bolts. Over the years I've gotten better at "knowing" a metric bolt size by sight, It's taken years of doing to get even a fuzzy recognition.
> 
> I think the brain gets locked into thinking in certain terms at a fairly young age, probably early 20s at the latest. After that you become kind of locked into what you learned as a youngster. I'm 49 yrs old. I suspect that most guys my age are in the same boat. )



I can relate to that, when some one says a few thou or hundreths of an inch I have an idea of the size, but when some one says a few millimeters or a few tenths of a mm I have no clue.

But for me bolt heads are different, when I see one I can usually make out what size it is in both SAE & metric. That's because I used to work in automotive.


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## John Hasler

Cobra said:


> In this country we solidly on the fence!  Metric to drive or by flour, SAE to build houses, and both in machine and maintenance shops.
> Overall not a big deal to adjust as you need.  I think there is too much existing equipment and supplies to make a total change any time soon.



Society of Automotive Engineers to build houses?


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## darkzero

John Hasler said:


> Society of Automotive Engineers to build houses?



I used to wonder about the SAE designation for screw threads.... not sure about the building code thing, he probably just used the wrong term but we get the general idea.




> United States Standard thread (USS thread), also known as Sellers Standard thread, Franklin Institute thread and American Standard thread, is a standard for inch based threaded fasteners and washers.
> 
> *The USS standard is no longer supported. It, together with the SAE fastener standard, was incorporated into the Unified Thread Standard.* However, the term, USS,  continues to be used occasionally today to describe inch based threaded  fasteners with a coarse thread pitch and inch based washers that are a  little bit larger than the corresponding SAE washer. The Unified Thread  Standard uses the term UNC (Unified National Coarse) to describe a  fastener that previously would have been designated USS and the Unified  Thread Standard uses the term UNF (Unified National Fine) to describe a  fastener that would have *previously been designated SAE*.






> *SAE International, formerly the Society of Automotive Engineers*, is a U.S.-based, globally active professional association and standards organization for engineering professionals in various industries.


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## MCRIPPPer

im guessing SAE is metric now? it seems all modern cars use metric parts.


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## toag

I am quickly getting my metric mics and depth gauges when i can.  Good news is most metric go cheap on ebayz.  I have digital for 0-1 so metrics covered there.  i think it is easier to "go metric" if you use CNC, since the machine can quickly convert.  the parts i am planning to make are metric, and it was a bit of effort to wrap my head around what 20 mm looked like size wise :rofl:


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## darkzero

MCRIPPPer said:


> im guessing SAE is metric now?



Nope. Metric is metric.


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## MCRIPPPer

darkzero said:


> Nope. Metric is metric.




well, sae is not a measurement system is it? does the society of automotive engineers use metric maybe?

not sure why people call inch-pound system SAE.


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## John Hasler

MCRIPPPer said:


> well, sae is not a measurement system is it? does the society of automotive engineers use metric maybe?
> 
> not sure why people call inch-pound system SAE.



This is the first time I've seen it done.  The proper name for the inch-pound system used in the USA is the US customary system.  The one formerly used in Canada and the UK is the Imperial system. It differs from US customary in subtle and not-so-subtle ways (Imperial pints are 20 oz).


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## FanMan

Nobody calls the inch-pound system itself SAE, but people often describe fine pitch inch size bolts as "SAE", because SAE set standards for them for automotive use.

As long as material suppliers sell only inch size stock, I'll be working in inches at home.  At work, it's a mix.  All of our product drawings are metric but all tooling and automation (my job) drawings are inch.

I find it amusing that friends in other countries buy 2x4 lumber and 1/2" copper pipe... by the meter.


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## darkzero

MCRIPPPer said:


> well, sae is not a measurement system is it? does the society of automotive engineers use metric maybe?



According to sources online, SAE is a designation that was for US standard/imperial screw threads & replaced by unified screw thread designations. Because of which many probably still tend to call these threads SAE. Sure, SAE engineers may use metric but it's not a standard they created. Common metric screw threads are ISO.




MCRIPPPer said:


> not sure why people call inch-pound system SAE.



Probably cause they don't know the proper term, usually they just mean "US system". As John mentioned earlier, the proper term for all US measurements is the US Customary Units system but you don't hear this term very much. I don't say it often either. It is not the same as the Imperial Units system although for screw threads & length measurements it's probably the same. For example an Imperial oz is not the same as an US oz but they're close.

The only real importance to me is screw threads, US & metric. I call them American (USA) standard & simply metric. With American standard threads being UNF/UNC & metric threads being ISO metric. There are other types of metric threads as there is with standard threads.


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## John Hasler

FanMan said:


> Nobody calls the inch-pound system itself SAE, but people often describe fine pitch inch size bolts as "SAE", because SAE set standards for them for automotive use.



Point.  However, the original reference was to the building trades.


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## Terrywerm

Do you guys have any idea just how tempting it was to respond in this post by saying only this: 



Metric??  What in blazes is 'metric'??   :noidea:




He heeeee.....


:gtg:


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## mattthemuppet2

I'm all confused at the best of times, but I'm starting to learn US SAE having been metric (to Imperial parents) most of my life. The thing I struggle with is figuring out what fractional drill or end mill is bigger or smaller than another. 5/64 vs. 3/32 is easy, just multiply the latter by two and 6 is bigger than 5. But what about 9/64 and 1/8? And so on. I'm crap at math and for big numbers I have to take my gloves AND socks off!


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## 09kevin

:roflmao:


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## uncle harry

John Hasler said:


> Society of Automotive Engineers to build houses?



I was wondering how long someone on here recognized what SAE really stands, ( or used to ) stand for.   LOL    &,..... Autocad uses imperial or metric to designate the choice of drawing formats. 

Numbers are readily converted between systems with the new technology (pocket calculators, cad-cam etc,)  The US is behind the norm but, with any luck, we'll survive all of this.


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## Hawkeye

I can guarantee I don't mean "US system". I sometimes refer to it as "English", SAE, Imperial or even"normal". Let's face it. Metric has a name. The old system really doesn't.

We had an interesting 'discussion' with a friend who sometimes rides with us. He's wondering why we still figure out our fuel economy in miles per gallon. Legally, we haven't had gallons since 1976. And yet, we still convert everything to mpg to see how our engines are running. He's right, of course, but I don't think it'll change in my lifetime.

Steve, no difference here from what Nixon tried to do. Lumber is still 2x4s, plywood is still 4x8 (but metric thickness). We used to build trucks in inches while the American company that bought us was already using metric.

No rhyme or reason.


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## savarin

Hey! you never know, when the US goes fully metric they may learn how to spell aluminium correctly.:roflmao:
(from someone who uses both systems often on the same project)


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## hvontres

I use metric at work and try to at home as well. Part of it probably has to do with the fact that all of the cast-off fastenters that seem to wind up in my Garage are Metric 
I have been using "bilingual" tape measures for my woodworking for a while now as well. I find that the metic side is a lot less confusing when it comes to marking and cutting short increments. I have always had a hard time keeping all of those fractional lines between the numbers straight. For my metal working, I am getting mostly digital mics and calipers so that they too can be "bilingual". 

And just remember, the official NIST definition of an inch is..... *25.4 mm*. So all of us have been using metric for quite some time now... even without knowing it


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## John Hasler

Hawkeye said:


> I can guarantee I don't mean "US system". I sometimes refer to it as "English", SAE, Imperial or even"normal". Let's face it. Metric has a name.



Yes.  The *International System of Units* (abbreviated *SI* from French: _Le Système international d'unités_)



> The old system really doesn't.



I suppose that there may not be any legislation formally naming it that, but the old UK (and Canadian) system seems to have been universally referred to as the Imperial system for nearly 200 years.


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## fast freddie

MCRIPPPer said:


> just want to see how many guys in the U.S. work in metric. i am committed to metric. i only own metric taps and dies, only have metric screws, only use metric tools, all the machines like mill, lathe, car, motorcycle are naturally metric (although my mill has imperial lead screws.) unfortunately i have to buy end mills and drills in fractional because it is rare to find metric versions in the u.s.
> 
> material is still fractional as well but it gets machined down anyway.
> 
> 
> 
> so shout out if you are metric and shame on you if your not! :nono:   :lmao:



I cut 2 shafts each 1 ft long on my lathe. first shaft was 1 inch dia. and 2nd shaft was 25.4 mm dia. and yes the 2nd shaft was much more precise and more modern. my DRO knows both ways, what's the big deal ?


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## nightowl499

as hillary clinton might say , what difference does it make !  numbers are easy to go from one to the other if i need something metric thats the way i make it ,  i dont see how the length of some ones foot is much more odd than using the circumference of the earth, actually i can relate to a foot a little easier


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## Barnesrickw

Worked in a water analysis lab, used metric.  Took science classes in college, used metric. Own Saab's, use metric.  If my lead screw was in metric, I might be tempted, but still all my other tooling is in inches.  I've noticed on the UK version of TopGear they still give speeds and distances in miles.   And saying "two or three thou" just sounds more Marlboro man than a few tenths of a millimeter.  


Sent from my iPad using Tapatalk


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## Marco Bernardini

Just my 0.02 euro as born-metric.
We are mainly confused by fractions, because generally the only one we use is the "half", like half a metre and so (quarter is just for time, never for length).
Then, when we see something like 27/64, we can't immediately understand if it's more than 5/8 or 5/16.
Probably seeing 1/2" as 32/64" and 3/8" as 24/64" would make it a lot easier for us, and a "BigFoot" made by 100 inches would even be better!
BTW, was the Rapidograph 0,2mm numbered 0.00787402 inches?


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## 12bolts

We have had the metric system here is Australia since 1974. I was 11 when they changed over. I still use both systems even now. My children know the basic imperial units and can convert some of them readily.

As honorable as this is





MCRIPPPer said:


> .... i am committed to metric. i only own metric taps and dies, only have metric screws, only use metric tools, .....


you will still need to use imperial measurements, parts and fittings. If you need to change out 1 stud in a part that has 20 more fractional threads, are you going to have 1 odd fastener, put a frational part back in, or will you change them all? On machinery that has imperial connections, (hydraulic line fer instance) are you going to fit 1 odd connection?



hvontres said:


> ....And just remember, the official NIST definition of an inch is.....25.4 mm


I have seen this written before, and it fails to explain to me how you can choose an arbitary number to convert mm to inches. I know its not much, but when you are already working to tolerances of less than 0.0001" commonly nowadays, how do you machine to such a broad tolerance?

Cheers Phil


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## Rbeckett

That was why I had both styles, because being an auto and big truck mech youre going to use both all the time.  I prefer metric though because it all fits together so neatly when you are working with decimals and parts of whole unit measurements.    I have even used both on the same trucks from time to tile.  The body and frame is metric and the engine and trans is inch.  What a PITA that is too,

Bob


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## hvontres

12bolts said:


> I have seen this written before, and it fails to explain to me how you can choose an arbitary number to convert mm to inches. I know its not much, but when you are already working to tolerances of less than 0.0001" commonly nowadays, how do you machine to such a broad tolerance?
> 
> Cheers Phil



Actually, it's not really an arbritrayry number. It is just the ratio of the length of someones foot to the circuference of the earth on the meridian going through paris 
Here is the Wikipedia entry on it:
http://en.wikipedia.org/wiki/Inch#Modern_standardisation

If it makes you feel better, the ratio is 25.4000000000000000000


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## JoeSixPack74

I learned with fractions and all of my metal working machines are inch machines.  But with cars, motorcycles and ATMs they are all metric or a mix of both.  I don't see the fraction system going away.


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## WesPete66

The metric system is clearly a cleaner, less confusing system to use as it's a base 10 system. With that said, I still use inches/Imperial when given the choice. Why? Because most of that around me is as such. Lumber is 2x4, 2x6 etc and sheeting is in 4' x 8' sheets. Insulation is manufactured accordingly to fit those sizes, etc.  Plumbing is fractionally sized, conduit is inches & electrical wire is AWG (American Wire Gauge) rather than mm squared (mm2). My metric threaded car still uses 14" wheels/tires. on & on...
I work for a manufacturer of hydraulic components. It would be cost prohibitive to build an actual metric hydraulic cylinder in the US, due to the unavailability of metric sized tubing, seals and components. Yes it's available, but here it's gonna cost ya! And why? Because our industry is tooled for inch/imperial sizes, and it would be a great financial cost to convert! (And we all know who pays in the end, right?)
So it goes much farther than that caliper in my drawer, or knowing the ratio of 25.4/1. Until industry as a whole converts to using metric not much is going to change.:leaving:


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## Barnesrickw

Rods, leagues, inch, foot.  All not exactly standard, but based on a measure of the human body, or how far a group of soldiers could walk in a day.  Metric does not have that connection. 


Sent from my iPad using Tapatalk


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## John Hasler

12bolts said:


> We have had the metric system here is Australia since 1974. I was 11 when they changed over. I still use both systems even now. My children know the basic imperial units and can convert some of them readily.
> 
> As honorable as this isyou will still need to use imperial measurements, parts and fittings. If you need to change out 1 stud in a part that has 20 more fractional threads, are you going to have 1 odd fastener, put a frational part back in, or will you change them all? On machinery that has imperial connections, (hydraulic line fer instance) are you going to fit 1 odd connection?
> 
> 
> I have seen this written before, and it fails to explain to me how you can choose an arbitary number to convert mm to inches. I know its not much, but when you are already working to tolerances of less than 0.0001" commonly nowadays, how do you machine to such a broad tolerance?
> 
> Cheers Phil



The US inch was defined as 1/39.37 meter (25.4000508mm) in 1866 and redefined as 25.4mm in 1959.  The first definition is stll used for the survey inch: the difference is 2 ppm, or about 1/8" per mile.


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## GK1918

09kevin said:


> View attachment 72185
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> 
> 
> 
> 
> 
> 
> 
> 
> :roflmao:



Hogshead???? that is fractions period.    circa 1920's Ford hogshead transmission cover


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## GK1918

Tell ya this;   customer, come in with a broken metric bolt of 334938483 mm. which comes out to 3/8 thats what he gets. Never had in
school its stupid  good thing is when a 1/2 rounded nut you bang on a 14mm.  so .500 or 1/2 inch its easy than-- 14mm  (.5 vs 14)
one half of anything is a half of it   so why get all involved with carying a not book. I have some but I only got two in my head like
14mm is a 1/2, 10mm is 7/16 thats it..   

1955 we were indroduced to the dewey decimal system in school,   Oh boy- we learned it mastered it so it stays.  showin my age yep

bottom line is, if you need this across the pond stuff dont come here...


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## uncle harry

GK1918 said:


> Hogshead???? that is fractions period.    circa 1920's Ford hogshead transmission cover




I seem to remember that a hogshead is some type of barrel or keg for liquid measure. How Grampa Simpson knew this ?...probably from being stationed in the UK in WWII.


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## John Hasler

09kevin said:


> View attachment 72185
> 
> 
> 
> 
> 
> 
> 
> 
> 
> :roflmao:



.002 mpg?  My 56 Ford did better than that!


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## darkzero

GK1918 said:


> Never had in
> school its stupid  good thing is when a 1/2 rounded nut you bang on a 14mm.  so .500 or 1/2 inch its easy than-- 14mm  (.5 vs 14)
> one half of anything is a half of it   so why get all involved with carying a not book. I have some but I only got two in my head like
> 14mm is a 1/2, 10mm is 7/16 thats it..



Actually....for a 1/2" bolt you would use 13mm & for 7/16" you would use 12mm unless your 11mm is worn enough to fit.


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## LEEQ

I use primarily imperial system. Unless the prints are metric or the thing I'm building parts for is metric. I have ready access to imperial machines and tooling. What I don't care for is the use of fractions. IE: I can buy a 3mm to 20mm collet set that is graduated 1mm at a time. It covers the ENTIRE range in between. I can buy the same set in inch and it has holes all over it's range. What utter B.S.!! Why not make them in thousandths and cover the full range like a metric set? So it will be that one of my metric purchases will be collets. The box will be labeled in thousandths as soon as I open it. By the way Europe used to be imperial and faces the same difficulty to a lesser degree. They can get metric tooling cheap and available if they so choose. Those old machines though, they think in imperial. I know metric math is easy, but really what dipstick decides to change everything? Why?


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## Walt

All my home shop carpentry and metal working measuring tools are inch-foot-yard.

I have metric wrenches for working on cars, because all autos at my household have metric fasteners. Still don't have any metric drill bits though.

At work, it's nothing but metric because I work in a laboratory. Volumes are liters, weights are grams, and lengths are meters. No other measurement system is used or would be acceptable. However, 1 liter graduated cylinders have 10-mL tick marks, while 2 liter graduated cylinders have 20 mL tick marks. It's best not to confuse the two.

Interesting that time systems are all the same. 10 hour days and 100 minute hours seem feasible, but you can't change the ratio of the Earth's rotation to its orbit. I certainly am not agitating for a 10 day week!

Walt


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## toag

I worked in a lab for a bit too, and most things were metric.
3 km/s was 3 um/us so conversions were quick and easy.  the only US measurement we did use was pressure.  I have no clue what a Pascal is, but I do get  psi


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## MCRIPPPer

anyone who thinks the imperial system is just fine probably only uses linear measurements. in doing scientific work dealing with volumes, pressure, and moles, metric is the only way to do it without going insane.


oh yea. pascal is just like psi. instead of pounds per square inch, you have newtons per square meter. (remember, kilograms and grams cannot be used as force!!!)


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## hvontres

MCRIPPPer said:


> anyone who thinks the imperial system is just fine probably only uses linear measurements. in doing scientific work dealing with volumes, pressure, and moles, metric is the only way to do it without going insane.
> 
> 
> oh yea. pascal is just like psi. instead of pounds per square inch, you have newtons per square meter. (remember, kilograms and grams cannot be used as force!!!)



Or better yet, thermodynamics.... What ins the world is  a Themal unit anyways... and why not use the italian one 
I college, I survived by converting the problem to metric and then putting the answer back into Empirial units when I was done. Thank goodness for that HP48 Calculator (which I still use 20 years later) 

And then there is my favorite non-metric thermodynamic unit: the *Ton of Refrigeration*. Anyone want to guess what that is all about... It's the amount of energy needed to melt one ton of Ice in 24 hours... I guess usefull back when we were converting Ice houses to mechanical refrigeration, but I am not sure that the average homeowner has a clue how his AC unit is sized. I also wonder how many plant engineers over designed the mounting for their 5-ton chiller units 

But in the home shop world, I don't think that absolute measurements are really that important. Since we are usually only making things in single quantities we can all use the Gesinte tolerancing system:
This Gesinte That


----------



## Marco Bernardini

Here is the photo of something curious I took in a medieval town not far from here: old measures used by the Republic of Genoa before the "metrication" by Napoleon I.




The sign can be roughly translated as:
_Ancient Public Standards of Genoese Measures
Cannella: m 2.22 » 9 palms
used for fabric,  rope, etc.
Canna: m 3.504 » 12 feet
used for walls, parcels of land, etc._

Wikipedia has two interesting articles about this:

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

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

Another thing to raise your hair: modern land surveying measure angles using the "gradian" (400 grads a whole turn) rather than the most common degree (360 degrees a whole turn).
It is faster to make mental calculations, but common angles (30° and 60°) become pretty fractional (100/3 and 200/3).

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

For a good laugh, the mayor of a small town told he will face a problem with a 365 degrees point of view…
 :roflmao:


----------



## darkzero

Marco Bernardini said:


> The sign can be roughly translated as:
> _Ancient Public Standards of Genoese Measures
> Cannella: m 2.22 » 9 palms
> used for fabric,  rope, etc.
> Canna: m 3.504 » 12 feet
> used for walls, parcels of land, etc._



The next time I drop by one of the big box hardware stores I'm going to ask for 30 palms of rope & see how much I get. :rofl:


----------



## uncle harry

toag said:


> I worked in a lab for a bit too, and most things were metric.
> 3 km/s was 3 um/us so conversions were quick and easy.  the only US measurement we did use was pressure.  I have no clue what a Pascal is, but I do get  psi



A Pascal is the French preference to measure pressure. The bar is used in the UK and,of course, the pound is preferred in the US.  With vacuum Torr was the preferred unit until The French & the Brits decided to "revolt".  Torr is based on Torchelli who we remember for inventing the barometer and who wasn't any of these other guys. Ironically Torr is based on millimeters. 1 Torr is 1mm of mercury which is what Torchelli used in his barometer.  It's the vacuum measure I've liked to use since 1957 !


----------



## Barnesrickw

Metric system is usually easier for solving the math, but I don't know by feel what a newton meter is.  I can guess what 12 ft pounds of torque is with an eight inch wrench.  I can see 1/4 mill in my head, and I know what a 200 yard shot is.  But that's what I've grown up with.  


Sent from my iPad using Tapatalk


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## chuckorlando

I dont see how one is easier then the other. Both are just numbers. Both can be as precises as you care to take them. I often use metrics for tap drills for standard. If your looking at fractions, well those are a pain till the light goes off in your head of the way they work. They seem dumb as the numbers dont flow in line lie decimal or mm. But who measures 15/16 anyways you measure the decimal


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## nightowl499

lets not forget  cubits,  hectars, and henways


----------



## uncle harry

nightowl499 said:


> lets not forget  cubits,  hectars, and henways





And then there is the Murphy's Law example; "data will always be presented in the least convertible form such as 'furlongs  per fortnight' "


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## GK1918

You all know what I think bout metrics !


Not allowed here


----------



## David Kirtley

I go either way. I don't like machining in mm though as the units are not that useful of a size. 100ths of a mm are too fine and 10ths are too coarse for my taste.

Now for the rants:

It is easy to poke fun at the origins of English/Imperial/whatever units but all measurements are arbitrary units. The meter was defined as the distance between two marks on a bar sitting in France. Only later did they move to different calibration to deal with thermal expansion and oxidation of the bar and to make creation of duplicate standards easier. As to the magical relation of the units to another (weight, length, and volume), it is meaningless. For instance, the coincidence of water at 0 degrees for cubic centimeter to the length of a centimeter and the gram is just a ridiculous rationalization to make it seem "scientific". It wouldn't have made diddly squat difference if they had chosen another relationship.

The fact is that unit conversions are not often that useful. You measure in reasonable units for a task and significant digits. You don't give your height in kilometers.  You don't fill up your car in milliliters. You don't buy land in square millimeters.

Then the metrification (is that a word yet? If not, I claim it's creation) of things just for the sake of lip service is silly. Bikes tubing is done in metric measurements but they are still 1 in, 1-1/8 and 1-1/4 in tubing as an example. My 355ml soft drink can is still 12oz. You still buy a quart of oil even if it says 0.943 ml on the can.

Then you get to the availability of metric items. Go to Home Depot and check the price difference for metric fasteners (if they even have any.) Forget about drill bits.


----------



## Ulma Doctor

i need to have both types of measurement and use whatever is necessary for the task.
over the years i have used metric bolts to replace uss and sae bolts where a blind hole was stripped out of the casting/part.
a M4 is your friend when you have a stripped out 10-32, a 10-32 when you need to repair a M3
a M7 works well if a 1/4-20 gets fouled up, a 1/4-20 to repair an M5
a M10 will work for a 3/8-16 gone bad, a 3/8-16 will take care of an M8 or a 5/16-18 that have been stripped out

i have used heli coils, but i use then only as a last resort.
I like Keen-serts the best, but unfortunately you need a lot of surrounding material to install the insert.
if it absolutely,positively,has to work right now, i'll drill,tap and GO!!

Most of the machines i work on are made in Europe, I've had to become very comfortable with metric measurements and fasteners


----------



## Squatchhhammer

I gone through both an auto tech class and a machining class and I was taught the two measurement systems were called Standard (ie. inch, gallon, pound) and Metric. I just loved it when a domestic auto used both metric and standard bolts on the same engine.:angry:

If you really think about it, both systems are just arbitrary.That's how all measurement systems are, just someone saying "it should be this because ...". I just prefer Standard in the sense that it can convert 3rds better than a base ten system. Like a 3rd of a foot is 4 inches or 2/3's of a yard is 2 feet. Also the 10 system works just as well in Standard.


----------



## tertiaryjim

The base ten system makes a lot more sense.
I've still not used metrics enough to be comfortable with it.
Have had to determine different threads that were metric and turn new ones. Even some that weren't standard ( China Valves ).
Worked on a Westinghouse turbine built by Mitubishi and had no metric mic's. Had to convert everything.
When the turbine didn't match the prints the Mitubishi rep said " Ah, We make improoments!"


----------



## Marco Bernardini

The "metrication" is a two-face issue.
Who commonly use metric system (roughly the 3/4 of the world) generally try to avoid tools and fixtures requiring a supplemental set of "exotic" screws, wrenches, etc., just like U.S. machinists generally don't have metric wrenches (¹).
Some time ago I looked for a spring plunger with a cylindrical nose. I  found the perfect one in the States, but it was 1/4-20, requiring a  1/4-20 tap, an appropriate drill bit and a non-metric Allen key. Instead  of buying all those things I gave up and used a different solution.
Very often it's even impossible to merge the two worlds: if I have a tooling plate with holes every 50mm hardly I can screw a Kurt vise on it, thus I don't buy a Kurt but I look for other "metric" brands. (²)
And I restrain from speaking of 110V/240V power tools and main plugs… (³)
This double standard means a severe limitation to the U.S. export which, seen in a wide domino-effect, has a great influence on workplaces, economy, etc.
I think a "metrication" of some products will give a nudge to the U.S. industry increasing the number of potential customers, even if it will make things a bit harder for home shop machinists.

Marco

----

¹ A good reason to visit Europe: here metric wrenches and tools are a lot less expensive, and if you buy them during your holidays you can save on shipping… The best souvenir I brought back from the U.S. was a bag of 1/4-20 screws.

² At least Kurt has "hybrid" vises, with metric screws but holes spaced in inches. They are in the German literature.

³ Planning to travel abroad? Check https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets before!


----------



## John Hasler

Marco Bernardini said:


> The "metrication" is a two-face issue.
> Who commonly use metric system (roughly the 3/4 of the world) generally  try to avoid tools and fixtures requiring a supplemental set of "exotic"  screws, wrenches, etc., just like U.S. machinists generally don't have  metric wrenches



I don't find metric stuff difficult to come by.  Metric tools are widely available because of the cars and even the coop store in the village here has a modest selection of metric fasteners.


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## toolman

It is my lifelong dream to see that stupid metric system abolished in the U.S. and have everyone go back to using fractions and decimals as God intended, oh wait, how many inches are in a cubit? Crap, so much for my master plan! :roflmao:


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## nightowl499

toolman said:


> It is my lifelong dream to see that stupid metric system abolished in the U.S. and have everyone go back to using fractions and decimals as God intended, oh wait, how many inches are in a cubit? Crap, so much for my master plan! :roflmao:



well a cubit is  18 inches on me , depends on how long your arm is ,, measured from elbo to tip of index finger

have to admit it is handy you always have it with ya


----------



## hermetic

I use imperial on everythng except my H mill, which is metric. I have a 0-1 metric mic, and a couple of 6"/150mm calipers which do both. As a matter of choice I work in imperial most of the time with metal, but when doing woodwork or building I tend to use metric, mainly because most builders merchants use it, and most sheet materials and timber are now supplied in metric, although timber lengths are quoted in metric but conform to the old imperial system using increments based on 1 foot/300mm. one thing I do find annoying is the fact that timber supplied as "50 x 150" is actually 145 x 47! 
           There is literally no need to convert! One thing that annoys me about the metric system is the ridiculous number of different thread forms and pitches which are nominally the same, but will not fit each other,  so its an 8mm bolt, but is it 1.0mm pitch or 1.5mm pitch,  metric form, or ISOmetric? Whitworth (the man not the thread) set standards so that a bolt made in Newcastle would fit a nut made in London, he did this by looking at all the different thread pitches and forms in use, and averaging them out. metric bolts are not "better" in any way than imperial bolts, and using a wide range of different metric pitches and forms for the same nominal bolt size is moving away from standardisation, a very bad idea indeed!

- - - Updated - - -

Also meant to add " All the rest of my metrology equipment is imperial.
Phil/hermetic


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## GK1918

Ok make me a believer    If   1" equals 25.40 in metrics? or .5 (1/2)  equals 12.70 in metrics.  why on earth would one cram their minds
with all those numbers>?  a half a foot is 6   6times 2 is a foot =12  half of twelve is 6 or decimal .5  at no time i went over three digits???   
I was never taught this; my take , its just stupid, should stay across the pond... whats the benefit?   I'm not a believer one rattiling
numbers around is smarter than ways we were taught back in the 40s...we proved that in 1945..


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## Taborclock

I use English unless I have to make a part for Russian Motorcycles, that I ride. They use odd thread pitches and get material from who knows where...You have to be flexible....) 
Exactly, how many mm in a tenth of a cubit ?


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## hvontres

Well, one advantage of being unit-agnostic:

I just picked up two Vogel DTI's off of Ebay for $20 shipped. They are .4-0-.4mm indicators (or 16-0-16 thou). So by going metric I was able to get a good deal and get a small bonus in range  And with DTI's, most of the time, you are just trying to keep the needle from moving, so wheather a line is 0.01mm or 0.0005" really makes verly little difference.


----------



## hermetic

GK1918, You misunderstand! I use both, so I never need to convert from one to the other. Whatever I start in, I continue in. I do admit that sometimes when measuring sheet materials I will use whichever system gives me the easiest to remeber units, so I often cut chipboard that is, say. 3' 9"x300mm exact! If someone gives me dimensions in metric, I can roughly convert in my head, 25.4= 1" 1M=39" 300mm=1'. For anything more complex I use a calculator, but it is very rare I convert at all. There is no need. That is why there is no need to "convert" to metric. Be versatile.


A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.

-Robert A. Heinlein


----------



## TOOLNUT

mattthemuppet said:


> I'm all confused at the best of times, but I'm starting to learn US SAE having been metric (to Imperial parents) most of my life. The thing I struggle with is figuring out what fractional drill or end mill is bigger or smaller than another. 5/64 vs. 3/32 is easy, just multiply the latter by two and 6 is bigger than 5. But what about 9/64 and 1/8? And so on. I'm crap at math and for big numbers I have to take my gloves AND socks off!



What might be a good thing for you is to get one of those flat plates with a bunch of holes in to represent the drill sizes, sometimes called a "Drill Index". Some of them have fractional sizes, and decimal sizes as well, marked on them at each hole.
Another pointer is to always watch for charts and scales that have both . A wall chart in the shop can be quite valuable. Some times one can set the digital calipers to a 'Metric' dimension,  and then push the 'USA' button to get a conversion, or vice versa.. 

A cheap pocket calculator from the dollar store is a valuable aid.  

I have worked with fractions and decimals all my life and when metric usage came along I had very little trouble with it except as some of you have mentioned, establishing a set of values to make comparisons with. I would suggest that you take a couple of familiar things like your 6 inch scale and remember how many mm's long it is, ( 6" X 2.54= 152.4 mm)
Round it off to 150 mm and you can learn to approximate other lengths using that as a start.. One inch is 25.4 mm)
This kind of math is really something that gets better with practice. Try to practice a lot.
If you are working these numbers as a hobby, who cares if it takes you a couple of minutes to work out as conversion with a calculator or a pencil. Remember,...practice makes perfect,.... or better at least.


----------



## hman

nightowl499 said:


> lets not forget  cubits,  hectars, and henways



Hmmmm ... was that Rowan & Martin or the Smothers Brothers???  :thinking:

Meanwhile, back at the ranch, I just ran across what looks like a pretty good set of online reference tables on another forum.

Give it a try!

http://www.numberfactory.com/


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## sambo

Metric? Metric? I don't got to use no stinkin' metric !


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## Barryg41

In Aussie land in the late 1960's the government of the time decided  that we will become a metric country NOW.   Trouble is that all  measuring equipment was is inch feet miles etc.  It was not legal to bring into mikes, rulers and other measuring tools into the country.    Materials in metric was extremely hard to find, even today small sections of brass is still in imperial sizes. 

In the last 3 years I have been back doing small machine engineering  .  Nothing over 100 mm   - 4 inches  diameter.  My machines are Genuine SEIG  C3 & S2 I have found my decision to go metric to be a good decision for me. 

Sorry I have not been logged for some time.  I have been in a dark place for a few months , but I can see the light at the end of the tunnel,

Cheers  Barry


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## Great white hunter

I work for a swiss company and everything there is metric. When I go home to my shop everything is standard. I rather use standard because thats what I'm used to.


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## Seabee-ken

I see this is a little older thread but I am still wondering if anyone has gone over to metric enought to buy a lathe setup for metric. I am planning on stepping up from a cheap hobby Asian lathe to a better Asain lathe, the PM 1236, and have been reading the forums here and other sites for about a month now and came across a few posters here that got a PM1236 that was set up metric from the start. The threading charts and all. I didn't even know that was an option. I use my lathe now for 95% metric because I mainly work on Jap and KTM bikes especially metric suspension components. I taked to Ray C about this and have decided to have him order me a metric machine. I hope I dont regret it...


----------



## Ray C

Seabee-ken said:


> I see this is a little older thread but I am still wondering if anyone has gone over to metric enought to buy a lathe setup for metric. I am planning on stepping up from a cheap hobby Asian lathe to a better Asain lathe, the PM 1236, and have been reading the forums here and other sites for about a month now and came across a few posters here that got a PM1236 that was set up metric from the start. The threading charts and all. I didn't even know that was an option. I use my lathe now for 95% metric because I mainly work on Jap and KTM bikes especially metric suspension components. I taked to Ray C about this and have decided to have him order me a metric machine. I hope I dont regret it...



Seabee...  LOL, you're killing me...  We get about 1-2 requests for metric machines a year.  The last shipment was supposed to have just one but that somehow got translated to 1 cargo container.  :banghead:


Anyhow, the vast majority of those same machines are sold in Europe and produced as metric.  The folks there of course do more metric turning than US threads so that's how they need/want the machines.  Anyhow, we have the next batches of machines of 1236's coming in soon and more batches due to arrive in late July and another in August.  I'm checking to see if a metric unit can make one of those two last shipments...


BTW:  Matt only sells in the US and Canada because of the UL/CSA certification requirements but, the factory that produces them (which Matt has been doing business with for 11 years) makes a lot of equipment sold outside of the US...

The only machines that I know-of that are truly universal (US/Metric) would be a CNC-type...


Ray


----------



## David Kirtley

Seabee-ken said:


> I see this is a little older thread but I am still wondering if anyone has gone over to metric enought to buy a lathe setup for metric. I am planning on stepping up from a cheap hobby Asian lathe to a better Asain lathe, the PM 1236, and have been reading the forums here and other sites for about a month now and came across a few posters here that got a PM1236 that was set up metric from the start. The threading charts and all. I didn't even know that was an option. I use my lathe now for 95% metric because I mainly work on Jap and KTM bikes especially metric suspension components. I taked to Ray C about this and have decided to have him order me a metric machine. I hope I dont regret it...



Back before I upgraded to a longer bed, I converted the leadscrew on my lathe to metric. I can't say it really changed my life. As I am only building for myself, I can choose whatever I want for thread pitches. I bought an extra gear that lets me get a better approximation of metric threads and find myself doing more threads with taps and dies anyway.

I don't think you will regret it. If you are doing most of your work in metric, it should make your life easier in the long run. You can still do SAE threads but they will be the ones that are off by a tiny percentage rather than the metric ones. I think you would have to be turning a really long screw before the error accumulates to something that would even be noticeable.


----------



## Seabee-ken

Back in the garage tonight using a die to cut some more metric threads. Metric machine will be nice. I did make a simple tool that holds a metric die in the tail stock so I can get threads started straighter. I see a lot of tools made to hold tools on this site. 

My little hiccup in my decision is gone now Ray and am still wanting the metric one. Thanks for the help yesterday.


----------



## EmilioG

I like both but use metric every chance I get. I just like it better.
It makes more sense to me. I think it's a better system.


----------



## dave2176

I do a lot of threading on my lathe. Since it has an 8tpi lead screw I stay imperial as much as possible.  if I needed to switch to metric I would look to change out my lead screw, etc. for a metric setup.
Dave


----------



## Guv

_I was fortunate to go through the transition of imperial to metric in South Africa in the sixtees . The biggest problem at the time was converting the monetary system from pounds,shillings and pence to metric rands and cents. There was 12 pennies to a shilling and 24 shillings to a pound as it was in Britain . Now the 12pennies had to converted to 10cents and 10 shillings to 1 rand,2 rand to the pound. We thought we were being robbed , and I am sure the storekeepers were taking advantage of the system. However the transsition went somehow smooth as I remembered as I was still in school. The older folks were not impressed. In my working life I worked in an automotive engine reconditioning shop and every journeyman had a complete set of metric and imperial mics. You don't want to grind an American crankshaft or block using calculators as this can lead to failures due to the close tolerances neccesary. Today 95 percent of the work is in metric but we still use our imperial mics etc on imperial engines. We never convert the specs.
_


----------



## petcnc

In my country we were born, raised and live in metric exept the plummers! They were born, raised and live in inches. 
Its funny! I just realised that when you need to order a pipe you have to say 1/2 inch 3/4 inch etc. It sounds natural here to associate pipe sizes in inches.
On the other hand when I lived in the UK I noticed that they had exactly the opposite system. Everything was measured in inches and miles exept plumming! This was in metric!

What can I say! Funny world.

Petros


----------



## bpratl

I have been finding that more and more of my layouts have both imperial and metric dimensions on them. Since I have added DRO's to my mill and lathe this has not been a problem since I can switch  the display on the fly. Boring for metric bearings is a pleasure with a DRO. Bob


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## Dan_S

I use both, because to me it's just a number.


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## bpratl

Dan_S said:


> I use both, because to me it's just a number.



That's the best way to explain it.


----------



## VFM3

My shop has stayed imperial.

I made some hex wrenches both imperial and metric sizes, but the tolerances for the blueprint are both imperial standard.

It doesn't make sense to me personally, but it is a lot less confusing for everyone else.


----------



## KBeitz

I still remember the day in school back in the _sixtees_  that our teacher said....
Well children today we will learn some metrics because is a few years everything will be metric.
Yea... Right...
I build and maintain textile machines so I need to use both. I also have a sawmill and we use 1/4's 
to cut all the lumber. It's a lot to keep up with. My choice is  imperial .


----------



## savarin

One annoying non standard I just found out about the other day when I was attempting to reduce solar system measurements down to scale is the number of zeros in a billion and a trillion.
I will let you search for the answers so as not to spoil the surprise.
Needless to say it was a pain.


----------



## dtsh

If the thread is gonna get resurected, I'll add my 2 cents.....

In general, I prefer metric. I've grown up with US Customary/Imperial and I'm pretty fluent in it, but what I *hate* about it is converting - even within other of it's own units.

I surveyed my own land and know that 1 acre is 10 square chains. For those paying attention, 1 chain = 4 rods; 1 rod = 16.5 feet, ergo 1 chain = 66 feet.
A 2 chain by 5 chain area is one acre.

A few years ago I was building a cistern, so who knows how many gallons are in a cubic foot?

How much does that 1 cubic foot of water weigh?

I find it much easier to figure in metric then, if needed, convert to something else.


----------



## Smithdoor

MCRIPPPer said:


> just want to see how many guys in the U.S. work in metric. i am committed to metric. i only own metric taps and dies, only have metric screws, only use metric tools, all the machines like mill, lathe, car, motorcycle are naturally metric (although my mill has imperial lead screws.) unfortunately i have to buy end mills and drills in fractional because it is rare to find metric versions in the u.s.
> 
> material is still fractional as well but it gets machined down anyway.
> 
> 
> 
> so shout out if you are metric and shame on you if your not! :nono:   :lmao:


----------



## StevSmar

Sorry to reinstate this zombie thread, I found some of the discussions relevant.

I grew up in a metric country and then moved to Canada. The lathe I’ve purchased has imperial screws on it (even though the bolts are all metric...lol). I’m looking at purchasing a copy of the “Engineers Black Book” which is available in either imperial or metric. It seems that all the Canadian sources for this book only sell the imperial version, making me think that this is the version I should get, even though Canada is a metric country...


----------



## westerner

dtsh said:


> A few years ago I was building a cistern, so who knows how many gallons are in a cubic foot?
> 
> How much does that 1 cubic foot of water weigh?


231 cubic inches/gallon, 8.3 pounds/gallon. Committed to memory several decades ago. I can work in metric, but I must convert to it from my original predisposition. I still cannot visualize 25.4 mm, but I can draw you a line REALLY close to one inch long.....


----------



## Forty Niner

MCRIPPPer said:


> just want to see how many guys in the U.S. work in metric.
> so shout out if you are metric and shame on you if your not! :nono:   :lmao:




I am moving to metric, inch by inch.


----------



## savarin

277.4196 cubic inches in a gallon UK 
1 litre has 1000 ml no matter where you are


----------



## silence dogood

Yeah, I can work with both systems.  However, the gal that I'm married to is SAE.  She fits that song "Five foot two, eyes of blue".  Convert to "159.385 centimeters, eyes of blue" just does not make it.


----------



## 7milesup

Meh, I will add my 2 cents.  Metric is sooooo much easier.  To bad 'Merca can't get its act together.
I was looking at my hex wrench sets the other day.  US measurements...All these numbers that are fractions.   Metric..... 0.5, .75  1.0. 1.5. 2.0.... how easy is that....
When I was flying some of it was in feet, then flight levels as you got higher.  Speed in knots.  Fuel in pounds but to tell the fueler how much fuel to put on board we had to covert pounds to gallons.  Then if we flew into Canada it was Liters.  So pounds to liters.  Or is that Litre?


----------



## hman

MCRIPPPer said:


> {Posted in 2014}actually the one thing i think will never change is carpentry. you will never see a 50x100 in the lumber store!
> although 2x4 and 4x4 means nothing anyway.


Well, nowadays {2020, and for several years previous}, plywood in the US is only available in metric thicknesses.  As for the 2x4, you're right -  they keep making it just a skosh smaller (claiming it's from having to plane the rough boards).  Who knows, it's probably planed to metric measurements nowadays ... though 8', 10', 12', 16' etc.are still the preferred lengths.


----------



## hman

petcnc said:


> In my country we were born, raised and live in metric exept the plummers! They were born, raised and live in inches.
> Its funny! I just realised that when you need to order a pipe you have to say 1/2 inch 3/4 inch etc. It sounds natural here to associate pipe sizes in inches.
> On the other hand when I lived in the UK I noticed that they had exactly the opposite system. Everything was measured in inches and miles exept plumming! This was in metric!
> What can I say! Funny world.
> Petros


... and even funnier when you realize that NOTHING about a ½" (or ¾") pipe is even close to ½" (or ¾")!


----------



## WCraig

Being in Canada, we've got a foot in both camps.  I believe my first hands-on experience with metric was my beloved 10-speed bike in the 1970's. From Canadian Tire, eh!  Had to buy a few metric wrenches to work on it...and I still have them.

Since I got into metalworking a couple of years ago, I've been looking for a set of metric taps, dies and drills.  They almost never come up in the auctions I've seen.  Once or twice, I've seen a cheap set of metric taps and dies (Canadian Tire again) but they've been bundled up with too much other stuff that I already have or didn't want.  Yeah, I'm a bottom feeder.

Re drills, I noticed the other day that tapping M4 usually specifies a 3.3 mm hole.  M5 needs 4.2 mm.  M8 6.8 mm.  However, I've yet to see a metric drill set that includes those sizes.  The more-complete ones I've seen go by 0.5 mm increments ala 3.0, 3.5, 4.0 and 4.5 mm.  

For inch measurements, we can buy a 115 drill set with letter, wire gauge and fractional drills.  For metric, I assume there is something similar?  What is considered a machinist set of metric drills outside of North America?

Craig
PS I know I can use letter/number drills before a metric tap.  Just curious what the rest of the world does.


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## Downunder Bob

when I went to school here in Australia, 1949 to 1960 I was taught in british imperial systems. We were taught that metric was a system used in Europe and the very basics of how it worked, but were not required to actually understand it. 

Then during my apprenticeship, 1961 to 1966, The factory that sponsored me had the import agency for some European vehicles, SAAB and Alfa. as a consequence of this we were required to know and at times use metric. 

A few years after completing my apprenticeship I became a marine engineer, and as some of the ships that I worked on were built in Europe they were fully metric. and others were built in Australia, or UK so we were constantly hopping from one to the other. I had to be proficient in both systems, and still am. Although all my Micrometers are imperial my verniers are metric. My lathe is imperial in as much as the lead screw is, but it's perfectly capable of cutting both metric and imperial threads even having its own 127T gear. 

I did find it very interesting when back in the late 60's early 70's I was working on Swedish ships, based in Goteborg, that we could get all our supplies as in nuts and bolts steel bar stock etc even angle iron pipe and tube in both imperial and metric and BSP was the standard pipe thread used on board. mAll the engineering staff were quite comfortable working in either system and even using a mixture, as in get me a meter of inch by 1/4 flat bar. PSI and Kg/Cm2 were often mixed up and also bar and atmos.

Australia began its conversion to metric in 1966 by changing the money from pounds, shillings and pence to dollars and cents, but it took about twenty years for the changes to be complete gradually changing things like temperature and then linear measurements until it was all complete.
I guess that one day USA will catch up with the rest of the world, it is a much easier and simpler system. I doubt it will be by government decree, but gradually as young people grow up being familiar with metric they will find it easier and less old people to complain. in about 100 years it should be complete.


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## kb58

When I need a hole of a certain size, I look at the drill chart and use whatever metric, numbered, or lettered drill is closest. The metal doesn't care what the units are.


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## Suzuki4evr

jumps4 said:


> metric is so easy compared to imperial all on a base of ten, not the length of some guys foot divided into 12 parts then divided by 16,32,64,1000,10,000 parts


I absolutely agree with this. Here in South Africa almost everything is metric,but I can do both. But IMO metric is much much easier than imperial. But I don't see the imperial system going anywhere so might as well learn to work with it or do the simple conversion.


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## Suzuki4evr

hvontres said:


> f it makes you feel better, the ratio is 25.4000000000000000000


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## Lo-Fi

My lathe is imperial, my mill metric. I have no DRO on either. I work in metric when machining, only resorting to imperial when I have to accurately turn something, but simply because my lathe is imperial and I work off the hand wheels. 

The railway is all imperial. Not UNC/UNF... Noooo. Whitworth. Some of it pre-war, some of it post war (different head sizes for thread size) and bastard pipe threads that the rest of the world has long forgotten. Sometimes some joker has turned a Whitworth bolt from a piece of metric hex stock. And some threads on the stays in the boiler have special taps that run an 11tpi whit thread from 7/16" right to 11/16. 

So I flit between the two. If measuring something roughly, I often do so in whole or half inches. Anything more precise than that and I'm going metric - fractions are just too silly to read on a tape measure. Whoever decided to measure sub inches in fractions rather decimal needs a stern talking to and time to think about what they've done! Lol. 
I'm a metric man, but the world refuses to let go of archaic, awkward standards. Why we still have miles on road signs and speed limits is beyond me too. 

Chains and rods, anyone?


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## dwentz

Everything is a number that is measurable down to a acceptable tolerance of about .001 inches, metric works with those numbers also.  I use both, but most my machines are in US inches IE .001. DRO's and digital calipers do the conversions for me at the press of a button. I will admit my Chinese lathe has holes drilled and tapped with US fasteners, and my Clausing mill has holes drilled and tapped for Metric fasteners of the DRO install. Its mix and match in my shop. I do most of my work in inches, but I have built a few projects that are all in metric.


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## StevSmar

I’ll (mostly) work happily in either imperial or metric lengths.

I have three annoyances:
- Fractions (if the fraction arithmetic gets too annoying, I’ll tend to switch to mm’s- though I did just put a dedicated fractional calculator on my phone which so far as soothed this annoyance).
- 1/8” is too similar to 1/10” (so I no longer use the 10th scale on my imperial rulers).
- 1mm is too hard to read (now...).

I tend to use:
- Meters for distances larger than about 8’
- Feet and/or inches for distances larger than about 15mm.
- mm’s for distances larger than 1mm.
- new glasses for distances greater than zero (I’m joking here of course...)


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## Winegrower

I am bidimensional.


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## hman

Better than being a one dimensional personality


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## pontiac428

I'm units-ambivalent.  After living in Europe for over 10 years, I just don't get hung up anymore.  Conversions work, DROs switch units with the push of a button, and the more interesting machines out there have dual-scale handwheels.  Today feels like 28 degrees C.  I lose money every time the exchange rate shifts the wrong way.  Liters just about equal quarts.  Metric units are based on universal constants, imperial units are based on the length of a king's foot or how much ale he could drink in an hour.  Okay, maybe one system makes more sense than the other...


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## Forty Niner

Ulma Doctor said:


> i need to have both types of measurement and use whatever is necessary for the task.
> over the years i have used metric bolts to replace uss and sae bolts where a blind hole was stripped out of the casting/part.
> a M4 is your friend when you have a stripped out 10-32, a 10-32 when you need to repair a M3
> a M7 works well if a 1/4-20 gets fouled up, a 1/4-20 to repair an M5
> a M10 will work for a 3/8-16 gone bad, a 3/8-16 will take care of an M8 or a 5/16-18 that have been stripped out
> 
> i have used heli coils, but i use then only as a last resort.
> I like Keen-serts the best, but unfortunately you need a lot of surrounding material to install the insert.
> if it absolutely,positively,has to work right now, i'll drill,tap and GO!!
> 
> Most of the machines i work on are made in Europe, I've had to become very comfortable with metric measurements and fasteners




*I so agree with you and have found a little helpful chart that allows me to pick smidgen smaller or a bit larger by bouncing between systems:*


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## NortonDommi

Growing up Imperial and the switch over to Metrickery taking place when I started taking exams and had to work in both, then entering the workforce where I had to deal with both systems my biggest bug bear is talking to people in supply industries who apparently have never heard of the Imperial system.  Example was an import salesman with English as a 4th or 5th language who was "A master plumber",(no such thing in this country),hand me 10 mm bolt when I asked for a 3/8" BSPT bung because " 3/8" and 10 mm are the same thing".
Their is still a huge amount of Imperial machinery in the world,(long may it stay),and sometimes fractions are just easier to work with. Having fractions and decimals to work with makes life easy.


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## GunsOfNavarone

I came out to my father (who was an OLD SCHOOL machinist) in the mid 80's....he said, "NO SON OF MINE!!!" I still cry over it. I was a closet metric guy for a couple decades. My wife accepts it of me and loves me for who I am. I buy nearly entirely metric now...I feel so free.


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## Janderso

I use both but I don’t work on cars anymore so I don’t use metric much.
I’m 63 and stubborn, set in my ways.


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## AndySomogyi

I make parts exclusively for cars, and ALL cars have been metric since the 90’s so my designs / parts are exclusively metric.

It’s such a massive pain that for some bizarre reason, all the machine tools that are available to home / small business machinists are all imperial. 

Doesn’t anyone else work on cars? 


Sent from my iPhone using Tapatalk Pro


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## Janderso

Imperial all the way. All my machine tools are Imperial. I don't work on cars anymore.


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## pontiac428

I don't understand the difficulty in multiplying/dividing by 25.4 to convert.  1mm is .040", that one you can do in your head.  200mm is 8 inches when you're working with a tape measure.  Badda bing, badda boom.  I guess if you need to cut a corner you can always use calipers in units that match your leadscrew dials.  Dimensioning drawings in either, or, or both imperial/metric is a check box you just click with your mouse.  Metric blueprints can be converted (what was that factor?  oh yeah, 25.4) with a pencil and calculator in a hot minute if your measuring tools and machine are both in imperial units.  There is nothing to fuss over.


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## GunsOfNavarone

I do cars, trucks and motorcycles. Metric all the way baby. I don't think anyone can make a good argument how imperial isn't convoluted. Is this 11/64th or 89/112th? Versus, is this 15mm or 16mm? all based on 100 not elbow to fingertips! 
I am trying hard to stick with imperial for machining...not exactly sure why, but it's not smooth and logical.


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## higgite

If a train travels at 140 km/hr, how far will it travel in a day? 

Oh, no! I have to multiply by 24. Not 10, 100 or 1000, but 24! How will I ever figure it out? Oh, the humanity!

Tom


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## GunsOfNavarone

Multiple what by 24? Why would I want to?
Can any one argue that 10, 100 and 1000 are much cleaner/easier to.work with than 12? There is little doubt that one day the world (USA) will jump on board with the metric system. you never 12 &13/64th in the metric system.


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## hman

higgite said:


> If a train travels at 140 km/hr, how far will it travel in a day?


Difficulty depends on what units you want for the answer ... furlongs, parsecs, rods, microns, ....


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## higgite

GunsOfNavarone said:


> Multiple what by 24? Why would I want to?
> Can any one argue that 10, 100 and 1000 are much cleaner/easier to.work with than 12? There is little doubt that one day the world (USA) will jump on board with the metric system. you never 12 &13/64th in the metric system.


Yeah, but you have to admit that 300 million meters per second doesn’t have quite the same je ne sais quoi as 1.8 trillion furlongs per fortnight.

Tom


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## macardoso

I do probably 80% of my work in imperial but I am totally comfortable with metric. My CNC can change units, but when I am programming it, there is a 3D model, the CAM program doesn't care about units until it spits out the final code. My lathe is imperial, but I do switch units on the DRO, so the only thing I have to keep in mind is the 8 TPI leadscrew.

My 1" micrometer and 6" calipers are nice digital ones and can switch units. The rest of my measuring gear is imperial. The surface plate hasn't decided yet...

Point being is I have no issue working in metric, but once I get beyond the size of my calipers and micrometer, I have to deal with unit conversion.


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## Boswell

I am with Macardoso on this. Metric vs Imperial is mostly a non issue now. Calculators are everywhere. Computers do the heavy lifting of any conversions. My 3d printer is Metric units, my CNC Mill is Imperial. I have digital mics that can switch units. My lathe had a digital DRO that can switch units. I keep both Metric and Imperial scales on my desk. I mostly do my thinking in Imperial but easily move back and forth so .... Non-Issue for me.


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## StevSmar

pontiac428 said:


> 1mm is .040"...


That would be great if it was true.
1mm = 0.03937007874”
It bugs me that there is not a cleaner conversion between mm’s and inches, couldn’t they have just said 25mm = 1”?

(Of course I’m being silly, for all intents and purposes 1mm = 0.039” is accurate enough)


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## kb58

I look at it like you're driving across the desert. Doesn't matter whether you're going 100kph, or 62mph, as both get you there in the end.


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## ch2co

Metric, Imperial, Whitworth I've got it all. Sort of a plain, but after 60 years of taps and dies and nuts and bolts......whatever it takes.


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## higgite

Do you measure a dead horse in centimeters, inches or hands?

Tom


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## homebrewed

higgite said:


> Do you measure a dead horse in centimeters, inches or hands?
> 
> Tom


Pounds.  Or, to continue the original thread, kilograms.


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## Flyinfool

All of my machines are old to where there was very little if anything metric in the USA. So of course they are all imperial. My hobbies and job both require a lot of both metric and imperial and my poor old brain seems to be able to think and visualize in either. A project I just posted on has a mishmash of imperial and metric on the same part to be able to use what I have on hand.

I do not want the USA to officially go metric, IF we do than all of a sudden it will be harder to find tools and meteorology to work with out old machines. It would be a PITA to have all imperial machines and all metric tools.


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## higgite

homebrewed said:


> Pounds.  Or, to continue the original thread, kilograms.


Nah. You weigh a dead horse in stones. And this one just keeps on getting heavier and heavier.  

Tom


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## hman

homebrewed said:


> Pounds.  Or, to continue the original thread, kilograms.


Aw c'mon homebrewed (and Tom and @higgite) ... if it's about horses, it's gotta be furlongs


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