Inch/lbs vs Foot/lbs

[turbo36]

Does it really make a difference?

Does anyone have a link to some technical document that proves one or the other is correct?

I'm an engineer and I have worked with both systems for over 30 years and have yet to find anyone that can tell me why the metric system is better. Yeah I know all about the system of "tens" and all that, but it is just as easy to make a mistake when measuring in meters,centimeters millimeters etc. etc. as it is in feet and inches. When I get a print in imperial it is in inches and parts of inches IE; 25.307" when I get a print in metric it is in millimeters and parts of millimeters 642.799. What's the difference??? A unit of measure is a unit of measure!

 

[RickB]

I'm an engineer and I have worked with both systems for over 30 years and have yet to find anyone that can tell me why the metric system is better. Yeah I know all about the system of "tens" and all that, but it is just as easy to make a mistake when measuring in meters,centimeters millimeters etc. etc. as it is in feet and inches. When I get a print in imperial it is in inches and parts of inches IE; 25.307" when I get a print in metric it is in millimeters and parts of millimeters 642.799. What's the difference??? A unit of measure is a unit of measure!

Thank you.

 

[jdbower]

I'm an engineer and I have worked with both systems for over 30 years and have yet to find anyone that can tell me why the metric system is better.

It's because for non-engineers conversions are easier and because we'd only need half the number of tools. Yes, they're exactly the same (that's why we have the ability to convert units) but how often have things gone wrong because translating between units was wrong either by our own doing or as a typo. The units also tend to be more self-consistent. I've only seen Nm in SI, but here we've had mention of ft-lbs, in-lbs, ft-oz - non-engineers often see "torque wrench" and then ignore the units.

Could be worse, we could live in the UK and use both for the same measurements (sometimes driving-related distances are miles, sometimes km) and still be stuck with figuring out how heavy a "stone" is Keeping around all the old systems of measurement is about as useful as saying we can still communicate in Latin and just translate back to English if we need to.

 

[turbo36]

I've only seen Nm in SI,

Design specs aren't only in Nm I have seen everything under the sun, how about Dyne-Meters???
dyne centimeter. Metric. Torque Conversion Chart
or this
The Newton metre should be written as N.m with prefixes to denote multiples of the with prefixes to denote multiples of the base unit e.g. MN.m (mega Newton metre). Divisions of the base unit are also denoted by prefixes e.g. cN.m (centi Newton metre) - see table (fg1) for full list of prefixes.

It is only easier if everyone uses the same unit of measurement. To me it's just as easy to remember 12 inches make a foot as it is to remember 1000mm makes a meter. [/quote]


[/quote]
Could be worse, we could live in the UK and use both for the same measurements
to.[/quote] No different then getting a machine in the US that has different JIC, DIN, or SAE fluid fittings on it - no system is perfect - the real argument is which system should the world use? The whole metric push was made by companies that wanted the ability to move production quickly to the lowest cost nation.

 

[SPYDERLK]

Lots of fasteners are rated in oz/in of torque.

Just for argument, do you realize it should be lb/in and lb/ft instead of in-lb or ft-lb?

Does it really make a difference?

Does anyone have a link to some technical document that proves one or the other is correct?

The reversal of terms : ft-lb, lb-ft is done to prevent confusing torque and energy. The ft-lb is an energy unit. In an engine HP calculation for instance it would play havok to get torque and energy confused.
larry

 

[jdbower]

The whole metric push was made by companies that wanted the ability to move production quickly to the lowest cost nation.

Now I see why you don't like the metric system (didn't realize globalization was such a big issue in 1791 ). Protectionism via obstrufication only gets you so far, though. It's much better to have people willing to buy your product because of higher quality or better price than to have them be saddled with buying a whole new socket set because you don't make fittings in the size they're used to.

I certainly agree about pipe fittings and wish they'd standardize on a single one too. But if you want to knock the metric system the best way to do so is by saying the fundamental measurement of weight is wrong. A person who weighs 140lbs on Earth has a weight of 0lbs in space. But a person with a mass of 65kg on Earth has a mass of 65kg in space. People should be weighed in Newtons, not kg.

 

[jinman]

Does it really make a difference?

Does anyone have a link to some technical document that proves one or the other is correct?

Google up any torque conversion chart and you will see the values listed as "force-distance" or the amount of force applied for a given distance from the axis of rotation. If you say, "foot-pound," it is putting the distance before the force. It's just a language thing and what we've become accustomed to saying in the US, particularly in the automotive industry.

Many years ago I developed and taught a class on torqing fasteners to assemblers and production people building the F-16. While doing my reasearch, I read an article about how/why we had come to say it backwards in the US, but I don't remember where I found that article. That was back in the pre-internet days when you had to go to a library and do research the old fashioned way.

 

[carpenter383]

Did you know there is a BIG difference between inch and foot lbs of torque?????

I was reading up on changing my trucks transmission fluid and adjusting the bands and didnt catch that the transmission band specs were given in INCH/lbs NOT ft/lbs...

I wonder how bad I would have messed something up if I had tightened the transmission bands down to 72 FT/lbs instead of the 72 IN/lbs specified..

It just goes to show you paying attention to details really can make a difference.. LOL

Just thought I would share that tidbit of info..

Brian

You prolly would have broken the band, or bent the anchor. After the adjustment did you notice any difference in shifting?

 

[turbo36]

Protectionism via obstrufication only gets you so far, though. It's much better to have people willing to buy your product because of higher quality or better price than to have them be saddled with buying a whole new socket set because you don't make fittings in the size they're used to.

.

I'm really sick of people throwing out that "protectionism hand grenade" when their arguments start to loss steam in a debate. I wasn't trying to make this personal or political I was simply trying to point out weakness when one standards organization thinks their system is better then another.

The people who work for me are smart and hard working, their quality is beyond approach by anyone in the world and the products we design and build are to world quality so it isn't about good product versus bad, it is about cost of labor , plain and simple.

 

[jdbower]

Then maybe I misread your post, sorry about that if I inferred something I shouldn't have. We agree on a lot of things, like one unit of measure being essentially the same as another. Where we don't agree is that I would rather have one global standard (and democracy says most of the world uses metric so we are the odd man out) but you don't seem to think it's important what units we use. Whatever your reasoning it's simply a difference of opinion and obviously not worth arguing over since neither of us have the ability to actually change anything anyway.