Milimeters

[Lester Nicholson]

I'm 67 yrs old; I grew up with inches and feet, and can't seem to wrap my mind around millimeters. Was wondering if I am the only one with this problem? I can comprehend 100" but can't understand 1450 mm.   Nick

[Joseph Lijoi]

mm divided by 25.4 equals inches.

[Bob Reeves]

I'm 67 yrs old; I grew up with inches and feet, and can't seem to wrap my mind around millimeters. Was wondering if I am the only one with this problem? I can comprehend 100" but can't understand 1450 mm.   Nick

We are close to the same age, I have a year on you. I don't even try, if I find I must deal with metricmeters I pull up onlineconversion.com and convert it to something I understand.

[proparc]

I routinely work in both. I have come to the conclusion that you have to grow up with either system. You can't think naturally in both. While I really think we should have gone over to metric years ago,how do you start over a whole nation that uses English?

[Larry Wong]

I gave up on conversion I now I just use the other side of my ruler, it's a lot easyer , I 'm just a little older than you guys.  Just think out of my comfort zone  ✈

[Warren Wagner]

Lester,

Don't panic.   Being comfortable with metric measurements is not something that one picks up overnight.   It takes
years for the metric system to become second nature.  (I too wished that we had switched years ago.)  The one thing that helped me the most, was getting used to the metric tools for working on my Voltswagon based dune buggy.  After awhile
you do get the hand of it.

My suggestion for a conversion link, is the one supplied by Tower Hobbies.   It's a very simple conversion calculator,
and most all of the conversions that you will need, are right there on ONE page.

     http://www.towerhobbies.com/help/convcalcs.html

I keep a link to that calculator right on my menu bar on my web browser, for quick reference.

A couple of simple memory aids are:

     1) One mm is approximately 0.040"  (40 mils)

     2)  One inch is approximately 25.4 mm

Cheers.

Warren


 

[Randy Ryan]

As a design engineer I was forced into metrics. I'm 63

1mm= .03937"
1cm=  .3937"
1dm=  3.937"
1m=   39.37"

25.4mm= 1"

1cc= .061cuin
10cc= .61cuin
1L=   61cuin

With those in mind I was able to to relate one to the other. Now, after a number of years I am almost as comfy in metric as in inches, but not quite. These at least will give you a distance and volume relationship reference.

[David Hoover]

In Canada we 'officially' converted to metric in the late 70's but both systems are legal for commerce.  Speed limit signs are in kph and distances in kilometres with temperature in Celsius.  I don't have a problem with the direct measurements, it's the combos that are problematic.  After a 40+ year career in mechanical engineering (my education was all in the English system) I have a gut feel for what a ft-lb of torque is but a Newton-metre has me completely baffled.

[Lester Nicholson]

What started this thread was my August issue of Model Aviation. Seems that all the new airplanes are advertised w/metric dimensions which leaves me wondering what's big/little. I understand that the metric system is more accurate and makes the computer world happy, but, I graduated high school in 1965 and my brain works in English not metric. Thanks all for your help.   Nick

[Dale Hymanyk]

It might be easiest  to start with a single unit and just compare from there. For example 1000 mm is a metre, about 39 inches, just over a yard or 3 feet. Now using this thinking 500 mm will be half that or something around 19 inches. Being Canadian, I remember the conversion years as we had to begin using it exclusively in school from about grade 7, I'm 56 now. Switching over wasn't always without problems, Air Canada famously messed up on refueling a 767 and the plane ran dry and had to glide to an uneventful landing at an old air force base in Manitoba. Sick with it, you'll eventually learn to deal with it even if you don't learn to love it.

[MarcusCordeiro]

Yeah, me too, but the other way around...
I've been doing this kind of inch to mm and vice-versa for so long, both systems work for me. Well, the converter app on tyhe cell phone does help a lot though..

Marcus

[Howard Rush]

Use Google.  It has a very slick conversion feature.  Just enter into Google, for example,

3.2 furlongs in millimeters

and see what happens.

[RC Storick]

Use Google.  It has a very slick conversion feature.  Just enter into Google, for example,

3.2 furlongs in millimeters

and see what happens.

643737.6

[BillLee]

...
A couple of simple memory aids are:

     1) One mm is approximately 0.040"  (40 mils)

     2)  One inch is approximately 25.4 mm

...

Not approximately, exactly 25.4 mm

[pat king]

I design in both systems. It takes some time to get used to. I was educated in the Imperial (inch - pound) system. To do stress, strain and deflection calculations I have to convert the metric to Imperial and then do the calcs. Metric units for stress etc. might as well be dimensionless for my feeble mind. I am 68, graduated High School in 1962. I learned on a slide rule and still have my Post Versalog, I can still use it. I believe all young engineers should first learn to use a slide rule before they get a calculator. They do not have to estimate the magnitude of the answer so they do not know when they have made a mistake on the calculator. They believe the number the calculator gives them is gospel. I have had many engineers working for me that couldn't believe it when I would tell them they had the wrong answer.

Pat

[john e. holliday]

Do they even have a slide rule in school anymore?   I remember when I asked my son to measure a piece of balsa for me.   I told him to measure 3 and 3/16 inch on a piece of wood for the plane we was working on.   Here he is in high school of all places and could not come up with the 3/16's of an inch.   I tried my best to give him a lesson on reading the grade school rule we were using.   Didn't even bring up the thought of my three sided draftsman rule.

[Jim Thomerson]

For rough estimation purposes, looking at drawings with dimensions in mm, 100 mm is @ 4 inchs. So, for example, 850 mm would be around 26 inches.

[John Hammonds]

Try this, Sorry don't think there is a mac version available..

It will convert distance, temperature, volume, time, speed, mass, power, density, pressure, energy and many others, including the ability to create custom conversions.

http://joshmadison.com/convert-for-windows/

TTFN
John.

[Steve Thomas]

Australia converted to metric when I was in early primary school, so that's what I've grown up with and am comfortable with.  But I think if you use another system for any length of time, it becomes natural also.  At work things are in feet and nautical miles (but kilograms for weight!), and that is what seems normal and right. If I have to fly somewhere like China or Russia then altitude is in metres, which is completely unnatural despite my metric upbringing.  When I started back into CL I was thinking "what the heck is an ounce", but through frequent use, ounces are fine now.  Same with balsa - 1.5mm is about 1/16", 3mm about 1/8", etc, and I don't really have to think about it.

I think that if you really want to be comfortable with metric, you just have to force yourself to use it and think in it for a while, and it will become natural.  Otherwise, just keep doing whatever you're happy with, and that's fine as well.

[Paul Smith]

The English system works fine for England, the United States of America and the rest of the civilized world.

The French system was developed purely because the French don't want to do anything the English way.  On the plus side, the French system makes it simple to freeze ice and boil water.

[Tim Wescott]

For rough estimation purposes, looking at drawings with dimensions in mm, 100 mm is @ 4 inchs. So, for example, 850 mm would be around 26 inches.

That's what I keep in mind.

If I need to be exact, I just remember that one inch is exactly 25.4mm, and then I reach for a calculator.

I'm in Toronto this week teaching an engineering class, and getting cordially laughed at for having to deal with Imperial measurements in my work.

[RC Storick]

Ounces to stones although most planes weigh as much as BOLDERS. Some are big ones but the moment of inertia stays the same. Just ask Howard 

[Steve Helmick]

In my 37 years as a machinist, I found that having the proper tools to use for either system was a lot simpler than converting either direction. I did get metric drawings sometimes, and always multiplied MM x .03937 to get inches.  I have a tape measure that has graduations in both inch and "mealymeters", and recommend it. Craftsman, I think.   Steve

[Randy Cuberly]

Well,
it may not be too practical...but if you really want to become efficient at thinking  in the metric system all you have to do is study chemistry and work in a Chem Lab for a while...worked for me. 

Randy Cuberly

[Dick Pacini]

My 45 years in manufacturing meant that I had to be comfortable with both systems. 

The only thing I could never understand was knots, as in air and sea travel. 

I was in England many years ago and was asked how many stone I weighed.  Of course, I had no idea.

[Bill Johnson]

If you want to see where metric to US conversion, if done wrong, can really make for a bad day, look up the Gimli Glider. The Gimli Glider is the nickname of Air Canada Flight 143, a Boeing 767-233 jet, which ran out of fuel at an altitude of 41,000 feet. The flight crew had entered the fuel load in pounds instead of kilograms!

[Jim Kraft]

Not putting enough fuel in was a mistake, but not checking the gauges so they would know they were about to run out was a bigger mistake. How in the world would they not know they were low on fuel long before they ran out?

[EddyR]

I have worked on bicycles most of my life and all foreign bikes are metric and most of the US bikes are also. For some reason there is about 10 different size seat post in the most common racing bikes . Reynolds 531 tubing used in high end bikes has several different size seat tubes just to make it complicated. Spanish,French and English all have there version of Reynolds 531.
Ed

[PerttiMe]

Do you guys measure your airplanes in "modern" Industrial Inches or US Survey Inches?

 

[john e. holliday]

I have a set of suspenders or used to measure in inches.   Some of the guys in my might remember me wearing them.   Great for buying and selling balsa in lengths.

[Alan Resinger]

Paul,
Only 3 countries use the imperial system exclusively.  The US, Miramar and Liberia.  I didn't realize that was the extent of the civilized world.  Britain uses a combination of imperial and metric.  
The metric system makes perfect sense as it works with units of 10's.  When I first moved to Canada, I found the easy way to learn was to quit trying to convert to imperial.  Just grab a metric only ruler or scale and whenever you need to measure, just do it and see what the measurement is and get used to it.  It really is easy.
Alan Resinger

[Bill Johnson]

Not putting enough fuel in was a mistake, but not checking the gauges so they would know they were about to run out was a bigger mistake. How in the world would they not know they were low on fuel long before they ran out?

The actual tank gages were inop, which the pilots thought was OK under their MEL (minimum equipment list) because they had a flight management computer which indicated that there was still sufficient fuel for the flight. They were wrong about the MEL and the FMC had the wrong info because incorrect fuel load input. As in most aviation accidents, a chain of events led to their eventual, almost catastrophic, incident.

[ericrule]

One of my customers in Australia sent a small file a number of years ago. I works great and converts a whole lot of differen metric measurements into US. Please send me a PM (eric@rsmdistribution.com) and I will forward it to you.

Regards
Eric Rule

[Paul Smith]

Those old 327's, 409's, and 427's really had some horsepower.
The new litter engines just don't have it. 

2,000 bombs did a good job of busting blocks of meter-heads.

Metric food packaging is an effective way to cheat housewives.

[Steve Helmick]

Paul, you need to go test drive some new cars and trucks! Doesn't cost anything to look... Steve

[Brett Buck]

Those old 327's, 409's, and 427's really had some horsepower.
The new litter engines just don't have it. 

   I will go borrow back my (now sold) 4.6 liter Mustang. Or I will get into my current 3.4 liter little hot rod that will run 170+ mph. You run any factory-stock street legal car from the 60's with any of those engines. Straight lines, or road course. Then we will see.

    Brett

[Douglas Ames]

Ever grab a piece of metric balsa sheeting from your scrap pile?

IIRC Royal R/C kits had metric sheeting.

3mm - not quite 1/8", and not 3/32" either. 

[James_Mynes]

There's an app for that.

[Paul Smith]

Paul, you need to go test drive some new cars and trucks! Doesn't cost anything to look... Steve

I guess I'll have to if my old GM products ever wear out.

I remember a preliminary enginnering order for the 1982 Camero and Firebird (F-cars).
The cover said "THIS IS AN ALL-METRIC PROJECT".
Page 3 said: "Design mass - under 3,000 pounds."
Well, they made the designs weight, but not the all-metric.

[Paul Smith]

Ever grab a piece of metric balsa sheeting from your scrap pile?

IIRC Royal R/C kits had metric sheeting.

3mm - not quite 1/8", and not 3/32" either. 

Unfortunately much of our balsa and plywood is polluted with metre products.  They just label to 1/16", 1/8', etc to sell it here, but it isn't even close to true.

[Tim Wescott]

This is true for a lot of plywood that we use to be sure, but if you order balsa from an American company that cuts and sands their own balsa you will usually get accurate fractional dimensions. I order balsa sheeting in lots of several hundred sheets at a time and it is amazing to me just how accurate the sizes are in thickness dimension. I just checked some sheets at random with a vernier and the advertised 1/16-inch thickness was spot on.

Who do you get plywood from that actually comes in fractional dimensions?  I'm just so used to 1/8 = 3mm and 3/16 = 4mm that I've kind of gone with the flow.  Having plywood that matches my balsa would be kinda nice.

[BillLee]

Who do you get plywood from that actually comes in fractional dimensions?  I'm just so used to 1/8 = 3mm and 3/16 = 4mm that I've kind of gone with the flow.  Having plywood that matches my balsa would be kinda nice.

That's a WIBN (Wouldn't It Be Nice).

For the rest, there's sandpaper. (Not that I am an expert on sandpaper as all of my models will attest!)

[Howard Rush]

I remember the diesel Oldsmobile that Paul Smith had at the 1984 WC.  He pressed on the accelerator and put out a huge black cloud.  He was very proud.

[BillLee]

I remember the diesel Oldsmobile that Paul Smith had at the 1984 WC.  He pressed on the accelerator and put out a huge black cloud.  He was very proud.

I bet it was not measured in millimeters! 

[Herb Calvin]

I'm 74 and still don't know metrics. Don't know and don't care much.

[Brett Buck]

Hi Paul:

This is true for a lot of plywood that we use to be sure, but if you order balsa from an American company that cuts and sands their own balsa you will usually get accurate fractional dimensions. I order balsa sheeting in lots of several hundred sheets at a time and it is amazing to me just how accurate the sizes are in thickness dimension. I just checked some sheets at random with a vernier and the advertised 1/16-inch thickness was spot on.

   That's very interesting. I was getting a little dismayed at the SIG contest balsa that appeared to be over the 6 lb rating. Then I measured it and the 1/16 averaged something like .071. Take that into account and it was all right in the advertised density range. This was about 10 years ago.

    Brett

[Lauri Malila]

Also, especially with thinner balsa sheets, the density varies a lot wether the sheet is just cut with saw, or also sanded. Sanding tends to compress the wood a little.
But that's only an issue with indoor model balsa. With thicker sheets it can only cause warping.

Lauri

[jim gilmore]

I'm going to tell you the real answer but the censer may not allow me to say it.
Like the english language the us standard of measurment is a bastardized system.
Here we have inches,feet and yards and when we come to doing fine measurments we throw away the standard measurments and go to thousandths of  and inch. Which means the standard ruler is useless.
So we should have scrapped it years ago.
And embraced the metric system. where everything is 1,10,100, or 1000 th os a centimeter.
centimeter,milimeterm or meter. all being variations of the same thing.
But one must learn it without being give another standard to confuse the issue.
The big problem being that we all hate change. even change for the better.

[jim gilmore]

The actual tank gages were inop, which the pilots thought was OK under their MEL (minimum equipment list) because they had a flight management computer which indicated that there was still sufficient fuel for the flight. They were wrong about the MEL and the FMC had the wrong info because incorrect fuel load input. As in most aviation accidents, a chain of events led to their eventual, almost catastrophic, incident.

 The big problem with almost every chain is that the weak link is a human someplace in the chain.

[BillLee]

...
Most of the cutters have just one sander. They have to readjust it to each size balsa they run. You would think that they'd have presets on the dials for each size once they hit it perfect, but I suspect that, due to the density variations in balsa, it doesn't work that way...
...

Keep in mind also that balsa is sanded on BOTH sides. Consequently, it is cut quite a bit thicker than the nominal size, sanded one side, and then, after readjusting the sander, sanded to final size on the second.

Thin sheets waste as much or more of the balsa than is delivered, and that is the reason thin sheets are more expensive size-wise than thicker.