Engineering...Beyond the Classroom

Metric time too?

Of course not.

Why not again? Doesn't the same arguments for the metric system apply to adopting metric time?

http://en.wikipedia.org/wiki/Metric_time

The conversion of English measure to metric or from metric to English measure can be precisely done so that all parts fit together. So I see no reason it would hamper any industry. For the ease of global commerce would it make it easier if everything was one or the other sure. In contracting a part out to specific measure the contract states what that measure is and what system of measure is. When I receive the part it should comply with the contract.

But NASA has projects that have taken years to develop. How cost effective would it be to make this change in the middle of these projects. This not only asking NASA to change but every contractor to make the change. Every employee would be expected to learn the metric system. I would say with today's global economy most employees have some knowledge of the metric system. We are not talking about mass produced parts for the general public. All it would take is one person to make a mistake in the change from English measure to metric to cripple NASA for years.

Then the people that are pushing the change are not the astronauts whom life is on the line.

NASA should have second thoughts.

"The conversion of English measure to metric or from metric to English measure can be precisely done so that all parts fit together."

Not so fast. One thing that comes to mind is metric vs DIN, ISO, and inch fasteners. The same also applies to bearings and other hardware. It's not the conversion, but the fact that some components are not compatible with other components.

Additionally, NASA doesn't make its own parts, it uses contractors, who use subcontractors like myself, who intern use sub-subcontractors to get the job done. Simply demanding change is not going to make the change. There is such a long chain of suppliers and a long lead time for development that switching to metric is not easy.

We are moving toward metric, but it's inch by inch.

I did say any thing about it being fast. I said it can be done. If metric fasteners need to be used they will need to be spec out to the application. DIN and ISO are standards that need to be take in consideration on any application devices manufactured under those standards are used. I do believe these would fall under my statement about cost. Allot of rework involved.

So I stand by my statement!

The conversion of English measure to metric or from metric to English measure can be precisely done so that all parts fit together.

"There is such a long chain of suppliers and a long lead time for development that switching to metric is not easy."

I did not want to mention that in would take the acceptance and reeducation of the general public would be necessary. Good luck there. I remember the talk in school and the lessons on the metric system in school 40 yrs ago. How it would soon happen!!!

I understand. My point was that NASA is not a single entity in this and stands on the shoulders of many, many sub contractors, which stand on other subcontractors' shoulders, and so on and so on through a long chain of suppliers (such as myself).

Any change to metric ripples through thousands of other companies both here and abroad. Then there are parts and components ordered sometimes years in advance that fit into other components to make up a subsystem. It's a mess.

Hi ozzb,

I did not want to mention that in would take the acceptance and reeducation of the general public would be necessary. Good luck there. I remember the talk in school and the lessons on the metric system in school 40 yrs ago. How it would soon happen!!!

Yeah, I remember that talk about going over to metric too. Back then, since I knew conversions quite well, I thought: (naively) "That shouldn't be so hard."

Since I have been in manufacturing for many years, I now see the major issues in converting to metric. How much money would it take for a company to convert all of their dimension-specific tooling? What about reprogramming all of their CNC programs? What about the headaches of going about getting your customers to accept the changes you are making in the specs?

Personally, I have no problem converting. Industry however, is another matter.

Mike

One more thing - if we can get converted completely to metric, it would be better for all.

Nobody however, talks about metric TIME _{(except Roger Pink)}, and I think that is worthy of AT LEAST consideration.

Start with 1 (24hr) day and call it a Turn. Ten Deciturns = 1 Turn. 1 Deciturn = 2.4hr. 1000 Milliturns = 1 Turn. 1 Milliturn = 84.6s. 1 Microturn = 0.0846s.

But really, what should we base it on?

I also work in manufacturing we produce products for the construction trade. Can you imagine what would happen to a company if they told their customers that all measurement had to be in metric form. They wouldn't be in business long because the customer would seek out another supplier.

An article in New Scientist notes that NASA some five years ago agreed to comply with a directive that all departments of the U.S. Federal government move toward exclusive use of the metric system of measurement.

Hell when I was working in the shipyard building naval ships I heard that same s#it..........only difference was that it was 1992. The problem back then is the same as it is now, was the people.

It has to start in the schools. Stop using the standard and only use metric, from grammar school on.

If two trains are going to Memphis and one train is 225 kilometers away and traveling 70 kilometers an hour and the other is 150 kilometers away traveling at 20 kilometers an hour, which will arrive first............

p911

I live in a metric country (Oz) where all industrial tradesmen and engineers talk metric, yet when I go into the local trade shop they still sell thing in "5/8ths" or "thou". Possibly because the shops still buy lots of bits from the US.

The metric advantage becomes obvious when you start to calculate something, everything is consistent and there are few conversion constants thrown in. Things like Energy(heat), Energy(motion), Energy(electricity) all being equal just make life easier.

I remember that couple of years ago a $100 million NASA project failed and the reason was traced to error in program which failed to recognize that interfacing program was in Metric not English.

May be somebody can remember.

Medical field is all Metric and students in USA are already exposed to some Metric but the general population is not.

I was going to mention the same incident:

http://www.cnn.com/TECH/space/9909/30/mars.metric.02/

From a metric country (Canada) point of view, I say it is about time for the USA to go metric. Did you know that in the whole world only Lybia, Burma, and USA are not metric? I am an old f..t and grew up with the British system but have adopted metric after a decade or so of refusal. Yes we still have lots of non-metric usages but it is usually driven by our neighbour to the south. Science and weather has long used metric exclusivley but Carpenters and plumbers seem to be still using Imperial measures. Hey if your visiting from the states you will really love our posted speed limits of 100 (...km/hr that is). Oh well what the hay, it will happen to NASA and the USA eventually. Maybe yard by yard instead of inch by inch would be better for everyone. NASA should negotiate with the rest of the world and have everyone drive on the right side and do it inch by inch?

Not only will we love the posted speed but also be happy to note the sudden drop in weight to half of what we weighed down here.

I hope the hell they don't. I many times get drawings for fabrications dimensioned in metric with every measurement in mm and I am glad the smarty buddy of mine didn't think of dimensions screwing me over by mixing in other metric inches he could have used besides just giving all of them as mm. For the life of me I can't figure out why anyone decided to be have so many different names for the same allow.

He could have chosen to just use the simple conversion provided in the program. when he made the CAD drawing all he had to do is click a button and make my drawings with inch dimensions but the bastard chose to let me do the conversion our get out the tape measurer that has inch and metric their and try to use that dimension tool. It is amazing how they build these tapes that nearly guarantee when you pull it out that no matter what system you are using it will ALWAYS be marked on the other or "wrong" side of the tape.

Actually he quit doing this when he got to Chile on an installation to find that I had made a few mm mistake. Well it was blamed on me till I went back through and found and proved that it was his mistake. I had fabricated the spool as he had marked it on the drawing and I was very glad that I didn't have to pay for the few thousand bucks of re-work on the job.

My policy now is two have my guys check every measurement on these jobs where we get metric inches both ways and I do the conversions on all of the dimensions before they start the work and double check them in allow as well. It adds about 6-10% cost to the work but I simply pass it on to the client. I list it in my quote so they know it in advance that they pay extra for me to use this system. I also tell them if they provide us with regular inch their drawings and dimension us to do it the way we know and work best they get the cost deducted from their bill.

I have heard the so called advantages of having things broke down multipliers of ten is claimed to make the metric system better. We already have the decimal inch if we need to see things in this fashion. Why the heck do people insist on telling us how we need to disrupt our production and change over unless they are willing to pay the lost time and money it would cost us?

When I was in Middle school over 40 years ago they shoved the metric system down our throat with a promise that if we didn't learn and start using it in ten years we would be considered pretty much total idiots because it was a sure thing the USA would be totally converted by then or whole world would have passed us up if we had not.

Well I am still waiting and still dreading that day and if they wait a few more years to do make it a hard law I will have missed the whole thing. In reality and out of necessityI secretly learned the basic system although I would never own up to knowing the first thing about it and probably call anyone a liar that said I did.

I am glad of the fact we have only a few different ways to give a dimension such as" 1 yard, 3 feet or 36 inches long. While I still hear all the time that the metric system is a better choice of measurement in many if not all areas.(I seem to hear people that have to use it say this mostly) I sure am proud that pipe-fitting and welding are not one of these areas.

That is my metric story and true or not plan on sticking with it.

I use metric for measuring things so much easier.

I would think that NASA would be clamouring to use any single measurement system; considering the millions (billions?) of dollars that have been dubbed 'probe' and launched into space only to fail to operate because someone either didn't make the conversions or botched the calculations while making the conversion from imperial to metric.

To say that converting is cost prohibitive doesn't seem to account for the cost of increased failure due to mix-n-match measurements... Gotta love bean counters!

Metric beans?

Can I cook those in my imperial pot?

Murphy's Law explains why Metric for engineering projects is a good idea.

1a. 'If it can go wrong, it probably will go wrong'
1b) 'If it can't go wrong, it definitely will go wrong'

Mixing imperial and metric may be ok when making a bow by myself, but not on a space craft.
Del

Very nicely put. GA from me.

For goodness sake guys, metric is everywhere in "USA Imperial": number and letter drills, sheet gauge, CAD systems and CNC are all metric (+bilingual). "105" and "155" and a 'klick', spark plugs have been metric for quite some time.

The argument is over can people 'imagine' in the nomenclature, not much else.