Dear John, Thank you for your insight into engineering practice at NASA. I am fascinated to watch as NASA goes through its metrication process. It's the process that I think is important � the actual metric theory stuff is fairly simple and can be learned relatively quickly � it is the human and social process of metrication that I find fascinating.
Again, I have intetrspersed some remarks. on 2003-09-02 06.55, John S. Ward at [EMAIL PROTECTED] wrote: > On Monday 01 September 2003 00:04, Pat Naughtin wrote: >> Dear John and All, >> >> I have interspersed some notes from an Australian perspective. >> >> on 2003-09-01 03.13, John S. Ward at [EMAIL PROTECTED] wrote: >>> Hi, >>> >>> I'm a scientist/engineer working for NASA. The metric system is used >>> extensively at the Jet Propulsion Laboratory, but inch-pounds are still >>> dominant. >> >> What do you mean by the word, 'dominant'? Could you guess what proportion >> of measures (and calculations) are done in metric measures and what >> proportion are done in old (USA or UK) measures? Do you know of anyone who >> calculates the chemistry of fuels (for example) in kilograms and then >> changes their results to pounds when they have their results. I know thatin >> the brewing trade, there is a tendency to do this because the calculations >> are so easy in metric and so difficult in Imperial (or USA sustomary) >> measures. > > Hi Pat, > > The short answer is, everything made out of metal is made in inches, and the > large majority of most spacecrafts are metal. The large majority of > mechanical drawings are in inches, and most fasteners are "standard" (i.e. > they don't make sense in any units, but are specified in inches.) JPL is the > most-metric NASA lab, and yet inches dominate here. Other labs deal mainly > with manned space flight and legacy programs (Space Shuttle, Space Station), > which done almost completely in inch-pounds units. > > There is a very strong correlation between education level and metric usage > within NASA. Most scientists and Ph.D. engineers strongly prefer metric. > Thus, the really high-tech stuff like electronic device design and > fabrication is done all metric. Higher level requirements and interfaces are > also often all-metric. However, we eventually turn these designs and > requirements into inches drawings, because as far as I can tell no NASA > machinists think metric. > > Machinists make a big point to not do anything in metric, and if you give them > a metric drawing, they will pencil in inches everywhere, and make the part in > inches. Be fair to the machinists. Have they got things like metric lathes and metric machining mills. It might be necessary for them to pencil in the inches, fractions, and 'thous' simply because that is the only way they can set-up their tools to make the parts specified in the drawings. If I only had old lathes, I would be truly annoyed if the engineers kept specifying things that I couldn't easily make � I might even get annoyed at the units preferred by the engineers and try to avoid them. [For about 10 years, I worked with the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO)*, and from my laboratory to the lunch room I walked through the machinist's workshop � they were less than kind to scientists and engineers (*&#$ %^&$ (&#$% for instance) who specified units that weren't available on their particular range of machines. They were very proud of their workmanship and got annoyed when their job was made more difficult. Also consider that of all the people who change to metric, it is the machinists who have the most difficult task, largely due to the settings on their older machinery.] * CSIRO might be roughly equivalent to NASA in its composition by professions and by crafts. CSIRO has a high proportion of scientists, engineers, and architects. > To me, this seems like a lot of extra work and creates opportunity > for error. True. > Yet most machinist bear a grudge against the metric system, and > make it a point to avoid it as much as possible. They also make it a point > to train new machinists inches-only, New trainees have to be trained into the arcane ways of any craft � twas ever thus. On a more practical note, they have to be trained to use the available (old) machines, and if the culture of NASA is the same as every workshop that I have ever been in, it is the newest machinists who get to use the oldest equipment. > indoctrinate the anti-metric grudge, and This goes with the territory � literally the territory of the workshop floor � everyone else, especially 'higher-ups' is to be treated with scorn. It's an 'us vs them' thing. We all do it � for example, how's your opinion of senior management to-day? > avoid buying metric tooling. If this is true, it is a serious problem. This issue needs to be investigated and have resources (physical, financial, and human) thrown at it at soon as possible. In my opinion, this is not an issue that should be treated lightly, nor treated slowly. > Therefore, most engineers draw inches drawings. Is this a cop-out because the engineers and the machinists need to spend some time talking to each other? > The real reason the JPL is not metric is because there is no organized > conversion effort. This is a truly serious issue. Maybe senior management has not yet discovered how to go about it; maybe senior management does not regard metrication as a serious problem (they don't remember MCO); maybe senior management doesn't have the resources to tackle such a large all-embracing cultural change such as all of the the measures and all of the the measuring systems used by NASA. Whatever the problem, NASA needs to investigate and act on an 'organized conversion effort' as a matter of urgency. > Everyone is left to fend for himself. This is bad. This is espedially bad in an environment that includes scientific and engineering and craft components, as all of these are highly motivated by developing jargon words, jargon phrases, and even jargon equations to develop and define their careers within the professional group to which they see themselves as belonging. [After 10 years at CSIRO, ask me how I know!] > There is no clear > message what units or parts are preferred, or when to use which system. This is solvable, but it will require leadership from NASA's engineers, but leadership is what engineers are good at. > There is no training. If this is the case, it is appalling. Training is the cheapest component of a metrication program. Develop some metrication aims, specify some metrication goals, find some metrication training contractors (let me know if you want some help) and get on with it. As I said, training is the cheapest component of your metrication program, and if you use external contractors, you do not need to be saddled with an ongoing financial commitment. > There appear to be no rules, and no deadlines. Most > people blindly continue to design and buy all inch-pounds hardware and > equipment, apparently oblivious to two acts of Congress and an Executive > Order requiring NASA go metric. As I said, develop some metrication aims and specify some metrication goals. Use the acts of Congress and the Executive Order requiring NASA go metric as tools to convince anyone who will listen to help in the development of NASA's measurement aims and goals. > Yet at some point most hardware is truly > mixed. I'm sure its very common to have a 1/4" screw and an M6 in close > proximity in the same component. This sounds like engineering, so I'll duck. [We agricultural science persons, with our one year program of agricultural engineering should bow low and grovel before our seniors and betters.] > The crazy thing is, practically everyone here has high exposure to the metric > system and has had to learn to cope with dual systems. A well-planned, > organized conversion would be relatively painless and in the long run would > make practically everything easier for everyone. Unfortunately, the will to > get it over with does not seem to exist. Feel confident, John. You know and I know that in the end, NASA will be a fully metric organisation. The only doubt about NASA's metrication is how long the process will take. In this context it might be interesting for you to ask your colleagues these two questions. 1 Will NASA eventually be an all metric organisation? 2 How long do you think it will take before NASA is all metric? Sadly for you, when compared to other organisations that I have seen, NASA seems, so far, to have chosen one of the slowest possible routes to metrication. Excuse me if you have seen it, but I am reposting a draft document (with slight modifications) on the relative speed of metrication that I posted here recently (see below). Cheers, Pat Naughtin LCAMS Geelong, Australia Pat Naughtin is the editor of the free online newsletter, 'Metrication matters'. You can subscribe by sending an email containing the words subscribe Metrication matters to [EMAIL PROTECTED] Ways to go � to metrication Pat Naughtin Your posting about metrication at NASA set me to thinking about the possible routes to metrication. It seems to me that there are four main ways to go, with many others falling somewhere between these four routes. As you read this you might like to consider where NASA currently sits among these pathways. My four ways are: 1 The Worst Way To use this method, you essentially aim to use 'hidden old units'. Let me explain how to do this. Firstly, you convert all the old values in your work directly to metric, eg. if one of your spare parts requires an 18 inch component, you call this a 457.2�millimetre component, or a 45.72 centimetre component, or better yet you list both 457.2�mm, and 45.72�cm, and 18�inches, and 1' 6" in your parts list. Secondly you provide all of your staff with extensive conversion charts and booklets (that include the 457.2�mm value as well as some 69�432 others � 69�427 of which your staff will never use!) designed to fit neatly in the bottoms of desk drawers and to paste firmly on the insides of office cupboard doors � in these positions these charts and booklets can delay your metrication program for many years. These two simple techniques should delay metrication by upwards of 100 years and they should cost NASA heaps as they are clearly based on the idea of giving an illusion of metric progress while retaining our individual mindsets. Regard 100 years as the absolute minimum for this path. Consider the New York Stock Exchange as an example; by hiding the new (in 1793) decimal currency behind the old (in 1792) 'pieces-of-eight' in quoting stock prices, they were able to delay decimalisation of stock exchange quotes from 1793 until 2001 � a delay of 208 years � very impressive. Think also of the oil industry's barrels (1860s) and you will begin to see the delays that are possible. 2 The Nearly Worst Way This technique places its trust in dual measurements. You supply all staff with dual sided rulers and tapes, and copious quantities of conversion charts. You insist that all documentation is done using dual measurements, although it is rare for companies using this route to specify which takes precedence presumably on the basis that the random generation of precedence by each member of staff is the best policy for the company as it gives each member of staff freedom of choice. You can probably plan for this technique to take your company around 75 years to 100 years for its conversion. As an example consider the Kodak company who made their decision to use 16 mm B&W film in 1910 and 16 mm color movie film in 1929; they also decided to use photographic paper based on ten inches by eight inches sizes with multiples and sub-multiples of this inch size. This dual measurement has delayed metrication at the Kodak company for 93 years so far, but in 2002 they began yet another metrication effort � they might be able to make the transition within the 100 years that I suggest for this technique. 3 The Second Best Way Use centimetres. This way you can keep those lovely fractions in your vocabulary. Remember that using millimetres exclusively, almost completely removes the need for fractions (together with their attendant extra time and costly errors). Do not form a company-wide measurement policy � let each department form their own. In this way the manufacturing departments will eventually use millimetres as others do in their crafts; the office staff will eventually use inches and centimetres � as others who sew and knit use these measures; the sales staff will change their measures according to how they see their customers in terms of conservatism/progressiveness � in any case the sales staff often don't really care to know about measures (other than sales figures at the end of the month). It's hard to guess how long this pathway takes. I have direct experience of the textile industry in Australia and they are still struggling (while making snail-like progress) with metrication after 30 years � my guess is that it will take them at least another 20 years, so my estimate for the 'Second Best Way' is between 50 and 75 years. It looks like the Microsoft company are, in part, using this technique � when I try to use one of their drawing applications, I have to divide centimetres into halves, quarters, and eighths � very decimal! 4 The Best Way Use other people's experience. Find out where metrication has been successful anywhere in the world and simply copy their techniques. Form a measurement policy � by saying things like 'Of all the length measures available in the metric system, NASA has chosen to use millimetres, metres, and kilometres' and 'The centimetre will not be used in calculations and they will never be written down'. 'It is the policy of our company to use rounded metric values of components wherever we can � we believe that this will lead to a simplicity that will reduce errors in production, administration, management, and sales'. These quotations are adapted from Australian building literature of the 1970s. Using this technique the whole of the Australian building industry had essentially metricated in under a year, and if you count the laggards, definitely had completed the process in under two years. It seems to me that NASA has chosen a path somewhere between the 'Worst Way' and the 'Nearly Worst Way' to metrication � I wish you well � but there's no need to put the champagne on ice just yet, it's a long time till 2103, or should that be 2153. Cheers, Pat Naughtin LCAMS Geelong, Australia Pat Naughtin is a speaker, writer, and editor. Pat has written several books and he has edited and published many others. For example, Pat was the lead writer for the 'Wool' chapter of the Kirk-Othmar Chemical Engineering Encyclopedia, and he edited the measurement section for the Australian Government "Style manual: for writers, editors and printers". Pat is recognised by the United States Metric Association as a Lifetime Certified Advanced Metrication Specialist (LCAMS). --
