Metric vs Imperial Units

Mike13 wrote:What is slightly ironic is someone defending the american units using the bastardized unit of a "thousandth of an inch" That is simply machinists that realized that the american system sucked. They simply started applying the metric system with the standard unit of an inch in place of a meter.

The reasons machinists use thousandth of an inch is because that's appropriate for machining. Lengths are more arbitrary and simple fractions are rare. That doesn't mean thousandths are appropriate for everything like cooking or construction. Also, I don't see how machinists in 1857 were "applying the metric system" considering that system wasn't in use in the commonwealth until I believe 1965, and that it doesn't have anything to do with the meter. You may as well say the metricists were "applying the mil system" which is just as ridiculous.

Mike Brady wrote: Amen! Any machinist worth their salt that I have worked with have all been proponents of the metric system.

LOL, look at the religious fervor!

I respectfully disagree. I know many machinists who see no point in using mm instead of mils. Most modern equipment can do both, but most shops I'm aware of are mostly still using mils.

What, exactly, is the benefit?

Ball wrote:Most modern equipment can do both, but most shops I'm aware of are mostly still using mils. What, exactly, is the benefit?

Keeping with one system means maintaining less tooling. Tooling is expensive. With more modern CNC systems at a large enough scale, it's not too bad, but there's still a lot of tooling that is specific to inch and specific to metric, i.e. taps, drills, reamers, broaches, etc.

edit: broaches, not broachets

ntlhui wrote: Keeping with one system means maintaining less tooling. Tooling is expensive. With more modern CNC systems at a large enough scale, it's not too bad, but there's still a lot of tooling that is specific to inch and specific to metric, i.e. taps, drills, reamers, broaches, etc. edit: broaches, not broachets

I agree retooling is expensive, which is why in the US machinists are still using mils.

It's all so much easier if you work in rods, chains and furlongs. All you have to remember is that 5 meters are about a rod, 4 rods are a chain, and 10 chains are a furlong. So a 60m rope is 12 rods or 3 chains, and a 70m rope is 14 rods. What could be simpler?

Martin le Roux wrote:It's all so much easier if you work in rods, chains and furlongs. All you have to remember is that 5 meters are about a rod, 4 rods are a chain, and 10 chains are a furlong. So a 60m rope is 12 rods or 3 chains, and a 70m rope is 14 rods. What could be simpler?

The Burmese system? An "out-thaba" is about a rope length, and a "ta" is 1/20th of that. So when you start running out of rope, your belayer would shout "TA TA!"

Ball wrote:What, exactly, is the benefit?

Well uh I dunno about you but I like the way .025 looks rather than .001. :)

One case: All common metric taps have a very easy to understand relationship between themselves and the drill size needed for the hole. Subtract the pitch from the major diameter and voila you have your tap drill size and on top of that many of these drill sizes end up being whole numbers and if not they land on a half size which makes them useful for many other operations as opposed to being solely a tap drill. This may seem like a small thing but when a solid carbide drill costs $150-$350 usefulness becomes pretty important. I spoke of pitch earlier, well a metric tap gives you the pitch directly as opposed to TPI. Who the hell needs to know the TPI more than the pitch. Take 1/2-13 and a M14X2 tap. The 1/2-13 needs a 29/64"(.4531" yeah I'll totally use this for other stuff) pilot and the pitch is 1/13(.0769.....what?), the M14x2 needs a 12mm pilot and the pitch is 2mm. The feed rate is even easier, for the 1/2-13 you first need to come up with the pitch and then do the math .0769x300 (arbitrary RPM)=23.07IPM. With the M14x2 you already know the pitch(2) and the feed will be often be a whole number and if it is not it will be easily computed in your noggin as the pitch value is at worst x.5 or x.25 (unless you are doing the smallest or largest taps)

Plenty of machinists use thousandths of an inch and don't complain about it. That's the way they were taught, that's what their specs say and that's how the instruction manuals provide info. And...that's how a lot of American manufacturing is done.

So whether you think it could be better, doesn't change that many machinists work with inches and thousandths and don't grouse about "why don't we change to metric?" It doesn't make them incompetent or ignorant. It works just fine for them. That's just the way it is.

Ball wrote:I Fractions work well for construction and cooking. They suck for science and engineering. Weights (or mass) suck for cooking.

Incorrect. If you are doing it right, recipes are weighed out, usually to the gram. While you see volume measurements in home recipe books, the best and most precise way to measure ingredients for recipe creation is by weight.
Source: It's my job.

Woa, woa, WOA, hold on...

Dynamic climbing ropes over 70 meters actually exist, outside of "$PROFESSIONAL_CLIMBER got a custom super-rope for their 50 meter long enduro lunacy project" contexts?

Erik Keever wrote:Woa, woa, WOA, hold on... Dynamic climbing ropes over 70 meters actually exist, outside of "$PROFESSIONAL_CLIMBER got a custom super-rope for their 50 meter long enduro lunacy project" contexts?

Apparently they do....
fixehardware.com/shop/ropes…

I suppose people had the same reaction when 70s first came out....

FrankPS wrote: And...that's how a lot of American manufacturing is done. So whether you think it could be better, doesn't change that many machinists work with inches and thousandths and don't grouse about "why don't we change to metric?" It doesn't make them incompetent or ignorant. It works just fine for them. That's just the way it is.

Any automotive, aerospace, heavy equipment or medical work I have ever done has been metric and obviously if your are manufacturing parts for the world stage it will always be metric. So it really isn't "just the way it is".

Never said they were incompetent or ignorant. I was simply, albeit snarkily, saying that a machinist that has been around long enough to understand the difference would understand the advantage.

Mike Brady wrote:Never said they were incompetent or ignorant. I was simply, albeit snarkily, saying that a machinist that has been around long enough to understand the difference would understand the advantage.

So you're talking about a marketing advantage as opposed to a technical one?

Ball wrote: So you're talking about a marketing advantage as opposed to a technical one?

Not marketing or technical, just an obviously easier unit to deal with when it comes to Mfg..

It's my berfday and I'm going climbing for the next four days. While I'm away have funny doing things in the 4th decimal place and remember that my unit is waaay better than yours.

For machining/precision manufacturing: All drawings and most tools in the shop I work in have measurements listed in both systems...

Reading through this thread is so fucking confusing. Can someone please explain to me what ball's biggest beef with the metric is?

Personally I think we should go back old school and measure by like the knuckle length, shoulder to elbow length. Maybe start measuring pitch length compared to your height or maybe even by how many pieces of gear you place during the climb.

ViperScale wrote:Personally I think we should go back old school and measure by like the knuckle length, shoulder to elbow length. Maybe start measuring pitch length compared to your height or maybe even by how many pieces of gear you place during the climb.

Wait.....you don't do this?!? I do this all the time

Gunkiemike wrote: A gallon is 3785 milliliters

Well that's true, but only in the US and a few other countries I'm afraid. In the UK, a gallon is roughly 4.5 litres, (4546 ml. if you prefer) approximately 20% more than a US gallon. Surely one of the few instances where an item is smaller in the states than here in the UK!

And regarding the earlier post which asserted that timber is bought in the UK in 1.2m or 2.4m lengths, that's only because the old-timers in UK construction preferred imperial measurement. It's actually more usual for it to be 1220 or 2440mm, mm being the preferred SI unit. These lengths equate, very nearly, to 4' or 8'.

FWIW, I'm of an age whereby I use both imperial and metric measurement fairly interchangeably, with the exception of buying fuel or calculating fuel consumption. It's always gallons and mpg for me, even though it's sold by the litre.

Because, redneck

The secret formula for blasting a lander into Mars.
Metrics? We don't need no stinking metrics

My money is in dollars, not euros. Thank God. (this really has nothing to do with the metric system, but I wanted to throw it out there).