English Vs. Metric

[BenK]

I'm putting together a list of pros and cons for switching our shop to metric. I would like to hear what everyone thinks?

[Guest]

We don;t use the Metric system in the US because it sux

 

/thread

[Newbeeee™]

It's a lot easier as the units are 'rounder'.

The biggest mistake that imperial did was to use fractions - 47/64ths etc - WTF? If they had stuck with 0.1, 0.2 etc then imperial would have been good imo.

The only problem I still have (and probably will to the day I die now) is limits and fits ie if you're making a bit of tooling and want a thou slide fit, I have to convert in my head to 25 microns

[Newbeeee™]

We don;t use the Metric system in the US because it sux

 

/thread

C'mon JP get with the times

[Thee Starry™]

[Guyinthedesert]

We don;t use the Metric system in the US because it sux

 

/thread

 

+1000

[Thee Starry™]

[within a thou]

Cons you will be replacing all your measuring tools and will run into a tonne of resistance from your old school machinists. Another con would be having to convert your tooling.

 

Pros...

 

And this is from a Canuck who was raised learning both.

 

When I went to trade school in the 90's my instructors stressed that we need to learn both because when the baby boomers retire the imperial system will retire with them. His logic was they are to stuck in their ways but by the time they are ready to retire then everyone will make the switch.

 

I asked him well if it takes them 20 years to retire won't us Gen X'ers be stuck in our ways and the cycle will continue? My instructor had no answer to that question.

[Thee Starry™]

The metric system is one area where the inner city is far surpassing the rest of the country. Their ability to comprehend a kilogram, a 9mm and 10cc is amazing.

 

Can't make it through school, but they converted to metrics easily in the inner-city

[Del.]

The metric system is one area where the inner city is far surpassing the rest of the country. Their ability to comprehend a kilogram, a 9mm and 10cc is amazing.

 

Can't make it through school, but they converted to metrics easily in the inner-city

 

 

Every weed guy knows a kilo is 2.2 pounds.

[djstedman]

Metric or English.. who cares.. change Mastercam configuration files and either one is just as easy to program.. Digital Micrometers, Calipers, etc.. can convert back and forth.. and or divide and multiply by 25.4 to convert from one to the other.

 

We do lots of stuff in English and lots of stuff in Metric.. the only thing I can see that might be a pro for Metric is that in Metric the machine might hold a slightly tighter tolerance when given 1 Micron .001MM moves.. as opposed to in inch where its .0001 Inch .. That said our newer machines go out 5 places and in inch are able to go to .00001 resolution which is about less than one micron and such a small increment I cant really imagine a need to go smaller..

 

People running CNC machines should be able to operate a calculator and convert back and forth when necessary.. that said, If I had one serious suggestion about it.. it would be if a shop generally uses both.. its good practice to have Op Sheets specify both so conversion errors are minimized..

[Del.]

Often times on Metric drawings I see where the tolerance for a shaft and/or a bore will call out a tolerance of like H7. Now I have to get my chart out and look how that applies to whatever range the bore or shaft falls in, to calculate the tolerance. That SUCKS. Just put the damn tolerance on the print.

[CJep]

Converting from metric to inch to metric is rather simple in Mcam as well,...

In the calculable fields if you type in a metric value while running in the inch config add an "mm" to the value, it will be converted to the decimal equivalent.

Same thing for metric, add "in" to the value and the inch input will be converted.

[Newbeeee™]

Often times on Metric drawings I see where the tolerance for a shaft and/or a bore will call out a tolerance of like H7. Now I have to get my chart out and look how that applies to whatever range the bore or shaft falls in, to calculate the tolerance. That SUCKS. Just put the damn tolerance on the print.

+1billtrillion Del.

Lazy lazy lazy cad jockeys. Work out the size, specify it on the print and for ever more (the life of the product) NO-ONE ever has to calculate it again.

No mistakes ever again.

Also, my pet hate is cad jockeys who put the statement 'Dims apply after plating' when they call up 30 microns of hard anodise and give you a 10 micron finished size!!!

Drawings are a means of communication and should be explicit - no ambiguity or head ache.

Anyway back on track also I have noticed that 'metric' cad jockeys like +/-0.1 and positional 0.1 for holes and +/-0.1 for 45deg deburr/chamfers etc where in the good old (halcyon) days, you'd have +/- 10 thou for general and +/- 5 though for hole pitches etc.

So metrification has tightened things up in my experience, as well as the dumb arse lack of edgeumakation from the shape drawers

[within a thou]

Often times on Metric drawings I see where the tolerance for a shaft and/or a bore will call out a tolerance of like H7. Now I have to get my chart out and look how that applies to whatever range the bore or shaft falls in, to calculate the tolerance. That SUCKS. Just put the damn tolerance on the print.

 

Anyone who deals with this should download the MITCalc. It is a spreadsheet that you input your feature size and class fit tolerance and it gives you low and high. You can do this in metric or imperial

 

http://www.mitcalc.com/en/download.htm

[jeff]

Cons you will be replacing all your measuring tools and will run into a tonne of resistance from your old school machinists. Another con would be having to convert your tooling.

 

Another con: having to spell "TON" with 2 "N's" and an "E"

[Del.]

In baseball if you batted .300 it would give you a metric batting average of 7.62 and that just ain't gonna fly in 'Murica.

[gcode]

They told me in high school (in 1971) that the US would be metric in 5 years

That was obviously untrue.. but in college physics and chemistry classes we worked exclusively in metric.

I remember thinking what a PIA English was when I started working in US machine shops.

US manufacturing would be much better off making the switch to metric, but I don't see it happening

anytime soon, certainly not in my lifetime.

[Del.]

If they can put 3 languages on my bottle of shampoo then they can use both metric and english units.

 

 

Wetto es hairo and rubbo ino, rinso and repeato.

[Thee Starry™]

They told me in high school (in 1971) that the US would be metric in 5 years

 

 

Don't lie... They didn't have high schools back then! You mean, they told you that back in the one room school house!

 

Seriously though, they told us the same crap in the 80's I work with both metric and imperial, much like del's shampoo bottles, I can handle multiple languages

[Newbeeee™]

I work with both metric and imperial, much like del's shampoo bottles

C'mon Starry - I've seen that picky in the Movember thread ....you need as much shampoo as I do

[Del.]

Chicks dig it when you tell them you have a 9mm Pepe'. It sounds huge.

[within a thou]

In baseball if you batted .300 it would give you a metric batting average of 7.62 and that just ain't gonna fly in 'Murica.

 

But think about how cool the length of a home run ball is hit would look