Measurements - Total Confusion!

[PollyCymru]

I've been looking at measurements for the Mandolin kit and am now totally confused

what is .040" ? .060"? .090" ? .120" ? We don't have these measurements in the UK we divide our inches differently

Can anyone tell me what they are in Centimeters and Millimeters? I've tried to work out the measuremets in inches but just can't.

thanks in advance

Polly

[...and Master of None]

Go to Google and type ".040 inches in mm" (for example) into the search box.

[Marc Berman]

The measurements are in decimal notation. To the right of the decimal point you have tenths, hundreds, thousands ... of an inch.
So .10 is one tenth of an inch. .50 = 1/2", .250 = 1/4", .125 = 1/8" ...
You can convert them to millimeters by multiplying the inches by 25.4. .25 inches x 25.4 = 6.35 mm.

[MikeEdgerton]

Actually if you phrase it this way in Google:

convert .040 inches to mm

You'll get the answer ".040 inches = 1.01600 millimeters" at the top of the Google page and darned if it doesn't do it the same if you do it the way ...and master of none put it as well. All these years I thought it needed the "convert" in there.

[fishtownmike]

Don't expect us to help you because you guys use the wrong math system. Here is a good web page converter for this. Type in the .040 in the inch spot and it auto converts to mm.
http://mdmetric.com/tech/cvtcht.htm

[bennyb]

The short somewhat inaccurate, but easily remembered key is(fractional to decimal inches) 1/64 = .015, 1/32 = .030, 1/16 = .060, (then back to accurate) 1/8 = .125, etc. You can(and I have) use your spreadsheet program to print out a conversion table using fractional and decimal inches, and mm, but you'll be able to do it in your head in no time.

HTH benny

[Jim Hilburn]

Wasn't it the English who gave us the foot and the inch - 12 to a foot, and 3 feet to the yard? And then you have to split it in half then in half again till you have1/128ths?
And now you want centimeters and millimeters?

[Bernie Daniel]

Wasn't it the English who gave us the foot and the inch - 12 to a foot, and 3 feet to the yard? And then you have to split it in half then in half again till you have1/128ths?

You beat me to it. Indeed the "English System" came from, of all people, the English. However, the Welsh people might bristle a bit at being included in the rules of measures set done in the Magna Carta. Polly just remember that 1 barleycorn is about 8.5 mm and you will be fine.

[Ivan Kelsall]

Well,as an explanation - some time back our illustrious government,decided that in order to be more compatible with our European neighbours,we'd adopt the metric system ie. Kilometers,centimeters,also Kilograms etc. & dispense with our imperial measurements.
We did this in most things other than that our car speedometers were still in miles per hour rather than kilometers per hour.Most likely too many to swap out so they were left. Fairly recently,there has been a return to Lbs & ounces on the weights side of things,but children are still being taught using the metric system for measurement of length - all very confusing as exemplified by the OP.
There are a number of on-line converters for all sorts of stuff - here's one :- www.theonlineconverter.co.uk/
(what is .040" ? .060"? .090" ? .120 )
.040" = 1.016 mm
.060" = 1.524 mm
.090" = 2.286 mm
.120" = 3.048 mm
Hope this helps.
The other ridiculous part of this is,that having 'gone decimal' in our coinage ie.like the US currency,everything is in 'hundreths / tenth' parts - the OP doesn't recognise the decimalised dimensions. "We divide our inches up differently" No we don't,we're not supposed to use inches any more. On a rule - there used to be 3 different dimensional increments :- 1 inch was divided into halves/quarters/eighths/sixteenths & so on.
The other was the decimalised inch - divided into halves/tenths/hundredths & thousandths.
The 3rd was the metric measurement - centimeters & millimeters
It's no wonder the OP is confused. Maybe only slightly less than the idiots who enforced the change in the first place,
Ivan

[Michael Lewis]

We should all change to the metric system and get the transition over with. Once you get familiar with the metric system it is easier to use than the English system. But I do like thousandths of an inch!

[Rick Lindstrom]

Polly- www.wolframalpha.com does a really good job of this- just type in ".040 inch =" without the quotes, and hit enter.

Rick

[...and Master of None]

...and darned if it doesn't do it the same if you do it the way ...and master of none put it as well. All these years I thought it needed the "convert" in there.

I think when they first started out you did have to put "convert" but Google just keeps getting smarter and smarter. Pretty soon all you will have to do is think about something really hard and Google will do it.

[Jim Hilburn]

I wish they would have taught us metric when I was a kid but 60 years of inches and feet is hard to overcome.
However when I bought my thickness caliper made with the violin in mind, it was metric so now I can only relate to plate thicknesses in MM.

[Steve Erbe]

Here is a conversion figure to convert mm to thousandths of an inch. millimeter number times .03937
example; 19mm times .03937 equals .74803 inches. ( or 3/4 in )
Hope you can use this.
Steve

[Mario Proulx]

We should all change to the metric system and get the transition over with

You can never "get it over with". If y'all switch, you'll forever be in the limbo Canada is. All your homes, like ours, are built in feet and inches. Framed on 16" or 24" centers. Covered with 4x8 sheet goods or boards in 1/2", 5/8" or 3/4" thicknesses. When Canada converted in the 70's, we were to go all-in and "get it over with quickly". Well.... the gubmint spent millions of the taxpayers money to covert plywood, OSB and drywall plants to metric, and then all existing sheet goods removed from stock and replaced in one go. Within a week, the mistake was so obvious they had no choice but to revert. The metric sheets didn't even fit in truck beds, being wider than 48". That also meant that every home built to that day now required the carpenter/framer/roofer/drywaller to rip each and every sheet to fit the studs/joists/rafters/trusses. And they were a hair shorter than 8', so they would have had to ad a strip on the ends. Fun, no? They had to revert, but the gubmint insisted that thicknesses remain metric. Well, 35 years later, we all still cuss and curse these sheets. My home's built in inches, so any renovation/repair is shim-city to get the new sheet/board work. Need to make a header for that new window? Two 2x10s with a middle layer of 1/2" plywood or OSB gives you the correct width of 3-1/2", right? Good for you. Not for us.. Ask for 1/4" flooring underlay to match up the new floor to the old? I'm given 10mm underlay. 10mm is 0.393" and 1/4" is 0.250". Fun? Not!

Tools? Yup, all of them are metric and imp. Buy a measuring tape and one edge is marked in inches, the other in metric. The problem? Well, sometimes you have to use the other side of the tape to measure or mark something, right? right. More fun! Same with rulers; one edge metric, the other imp. Take note of how often you use both sides to mark something. Something as simple as marking how far inboard you're setting the strings on a nut, for example. Fun!

Your Mom's great recipes? Get the calculator out. Even setting the new oven takes a calculator or chart.

I don't hate metric. I detest it. I detest that I live in a country that will forever be in measurement system limbo. If your government ever proposes to switch, invite me down and I'll do a tour of speeches.

[David Collins]

That's a very good bit of insight Mario.

As to the original post of "I've tried to work out the measuremets in inches but just can't", those measurements are in inches. .040" is 0.04 inches, not much more to it than that. If you're trying to convert to fractions, don't. They aren't fractions, and once you get down to tolerances of less than 1/32" or 1/64" of an inch, you use decimals instead of fractions. Given that you'll be measuring things like plate thicknesses with calipers or micrometers anyway makes the idea of trying to think in fractions even less sensible. Machinist tools work in decimal whether they are metric, imperial, or US, and if you're working from plans written in one system you either use tools graduated by the same, or do your conversions.

Personally, I think we should all switch to "the Bob".

[Dale Ludewig]

Hey Mario, I understand the frustration. Well at least as best I can. When buying materials for the cabinet/ furniture end of my business life and need for lack of a better word 'marine grade' plywood, the stuff that's made of the thin little veneers approximating 1/2" thick to make drawers from: good luck. You can order baltic birch, but the closest you can get is 12 mm. So you order Russian birch which is pretty close to 1/2". Dado heads are in imperial. And all the sheets are basically 60" square. Unless you want to order a whole bunk, which I don't.

At least with instrument work, we're milling it to thickness ourselves.

[sunburst]

When I worked in the cabinet business too many years ago, we manufactured cabinets in the 32mm European system. We measured everything metric, worked in the system all the time and it was great! I resolved to continue using metric measurements, but hit the wall when I tried to find good metric measuring tools in the US. And by good metric measuring tools, I do not mean metric on one side and inches on the other; those tools are worthless (IMO).
So gradually, I've reverted to inches for most things.

It is not the metric system that people hate, it is the conversion from one system to another that people hate. Everyone I know who has had a chance to work entirely in metric measurements soon realizes that they like it much better, but converting from any measurement to any other, and working in two systems at once are horrible! Mistakes in measurement increase, things slow down, frustration increases.

So, nowadays I measure nearly everything in inches simply because my "inch" measuring tools are better and more numerous than my metric ones, and I can often be seen with calculator in hand converting from decimals to fractions, and writing down measurements like 1 1/2" + 1/32". I can find that on a ruler just by looking without doing the mental calculation that I have to do to find 1 17/32". I wish it was all metric...

[Jim Rowland]

52 or 3 years ago,when I was teaching a basic math course to high schoolers,I insisted that they learn the fundamentals of metric because the media was full of claims that a conversion to that system was imminent. 'taint happened. I guess it may have helped some of the kids who went into the sciences.
Jim

[peter.coombe]

We converted to metric when I was a lad, and now after around 30 years of metric, I hate feet and inches, pounds and ounces etc. We also converted to decimal currency in 1966, whcih was one of the best things we ever did. Now just about every thing is metric, but there are still a few remnants, so you can't really get over it entirely. Building materials and houses are built using metric measurements, and have been for years, so the problems described by Mario are no where near as bad. Renovating old houses can have problems, but nothing that can't be worked around. Cars are built using metric nuts and bolts, and speed is km/hr, fuel consumption is Litres/100km, land areas are in hectares. Problem is most people still think in acres and squares instead of sq m and hectares. Even now, a hectare means little to me even after all the years of metric. You also really do need spanners for both systems. Some things seem to be impossible to convert. We still have bolts and screws in inches and mm, and spanners in inches and mm, and drills, in the hardware stores. Caravans are usually measured in feet, although most manufacturers also provide metric measurements so that is very slowly changing. Most measuring tools are in metric, although you can still get dual system tools. It is not difficult to find high quality metric measuring tools, so I work almost entirely in metric. About the only thing I still talk in inches is for scale length, and occasionally thousands of an inch. Scale length in mm means nothing to most people (including me). So, even after around 30 years of metric, it is still not 100% metric. Weights and volumes seem to have been very successfully converted with just about everthing now measured in ml, Litres, cubic m, and Kg. Personally I think that what was successfully converted is far better off with the metric system. Pounds, ounces, tons and quarts, gallons are just horrible.

[Paul Hostetter]

Much as I love eighths and sixteenths, I do lots of things in 100ths and 1000ths of an inch. It's the best for laying out odd fret scales. Starrett makes wonderful rules marked out thus:



And micrometers come either way, whether old analog ones dedicated to inches or newer digital ones which flip from one system to the other with a button click. Big deal.



Metric is logical, but soooo boring.

[Keith Newell]

Here is the best way. To go from inches to millimeters divide by 25.4 --- to go millimeter to inches multiply by 25.4.
Keith

[Keith Newell]

I think it is not so easy to convert to the metric system. Here is a true story:
At my work we get new engineers every season fresh from getting their degree. They then proceed to design parts and want to make it easy for us in the shop to build the parts so they pick nice round numbers for material thickness, like 10mm (.3937"). We then call them up and ask "can we make this from 3/8" or 1/2" plate aluminum?" They say yes then say "oh wait, there are other pieces being made from outside vendors so it all has to match". So the answer is "no". We then ask them to come down to the shop and we give them a tour. We show them our round stock (rod material) for use in lathes, we show them all the sizes in fractions of an inch and explain our suppliers stock this and we can get it same day, we explain that for most metric sizes it is weeks away from being delivered or we have to take a bigger size inch material and have it centerless ground down to size for shaft material to metric sizes.
We then take them to the plate material of aluminum, steel, stainless steel, titaniam and various plastics and show them it is in inch thicknesses on the fraction and explain we just cant buy metric sized raw stock and have to buy it bigger then have it blanchard ground down to metric thickness. Either way we go it adds a huge cost factor to the project. We are a large company and have some clout on getting materials and we have this much trouble? Imagine how hard a small company has it.
If you look at most manual machinery like lathes and mills that have to be cranked by hand (Bridgeports, Laguns, Hardinge etc) and see that the dial from the hand cranks are in inches, either .200" or .250" per revolution then you will realize that if someone specs 3.2mm from point A to point B then you will be getting your calculator out, Period.
Keith

[Paul Hostetter]

Here is the best way. To go from inches to millimeters divide by 25.4 --- to go millimeter to inches multiply by 25.4.

Won't work on string gauges.

[Ron Hale]

Paul, he actually has his formulas reversed. He should switch his divide by and his times around, then it would be correct. But it's a pretty fruitless venture for measuring string gauge thousandths.

Ronnie