A question for you metric users....

fritter63

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So... in the imperial system, we have rulers/tapes that go down to 1/64", small enough that anything in between doesn't really matter (assuming you can still SEE to 1/64" on a rule!).

In the metric system, there only marks are down to the mm. Nowhere do I see any "half mm" marks, which would be closer to 1/64". What do you all do? What happens when you need to make something in between the marks? As in measuring ACTUAL dimensions on a project as it progresses (what I mean by that is that there is a point where I stop going by what's on the drawings and start using what I actually ended up!).

Are folks across the pond really so accurate that you don't need fine markings like that?
 
Most of my metric rulers do have half millimetre marks on them and I do use them on occasion.  I can get even more accurate with my digital calipers but have very seldom needed to do so.  It is wood that we are talking about measuring here, not some fine material where fractions of a millimetre matter.
 
Frank Pellow said:
Most of my metric rulers do have half millimetre marks on them and I do use them on occasion.  I can get even more accurate with my digital calipers but have very seldom needed to do so.  It is wood that we are talking about measuring here, not some fine material where fractions of a millimetre matter.

Remember you're talking to an amateur luthier! I've measured wood in thousands of an inch.... :)
 
fritter63 said:
So... in the imperial system, we have rulers/tapes that go down to 1/64", small enough that anything in between doesn't really matter (assuming you can still SEE to 1/64" on a rule!).

In the metric system, there only marks are down to the mm. Nowhere do I see any "half mm" marks, which would be closer to 1/64". What do you all do? What happens when you need to make something in between the marks? As in measuring ACTUAL dimensions on a project as it progresses (what I mean by that is that there is a point where I stop going by what's on the drawings and start using what I actually ended up!).

Are folks across the pond really so accurate that you don't need fine markings like that?

At that point I am no longer usually using a ruler. I am using story sticks, component pieces, etc. so I suppose the actual measurement becomes irrelevant.
 
To Frank's point, below half a millimetre and you're talking ~1/50", so you're not "marking" any more. Your marker / pencil starts to add to the error at that point!

This is a popular format of rule over here 30cm / 12" with metric / imperial conversion tables on the reverse side. 5cm is calibrated with 1/2mm detail and the imperial side has 3" in 32nds and 1" in 64ths.

[attachthumb=#1]

I have digital gauges for anything more accurate - but I've never got them out for wood!

Kev.
 
Like already mentioned we have rulers which do 0.5 mm

I can't ever see the need to go any more accurate than that for wood work.  End of the day the wood might of moved 0.25mm with weather change. 

I hate rulers with the 0.5 mm on does my head in rather they weren't their its easy enough to tick a mark between two lines to get 0.5mm.  Having all them lines just does your head in.

Jmb
 
Something I've noticed in youtube videos of Americans using Festool. They ALL look at the distance in mm.
Of course I can't speak for all, and it might vary from country to country, person to person. But in effect we Belgians use CM 90% of the time. (mm / 10)

So we don't say, for example it's 355mm, we say it's 35,5cm
It's A LOT easier to work with the smaller numbers like cm than with the larger mm numbers.

Just a simple tip that will probably alleviate a lot of the headaches Americans experience with the for them unfamiliar metric system.
And oh yeah, half millimeters are very common. For most of the rulers 1 side will be in millimeter increments, the other side in half millimeter
 
jonathan-m said:
Something I've noticed in youtube videos of Americans using Festool. They ALL look at the distance in mm.
Of course I can't speak for all, and it might vary from country to country, person to person. But in effect we Belgians use CM 90% of the time. (mm / 10)

well lol, i was thought that technically in woodworking the norm in Belgium at least, is to use mm for width and thickness, and meters for lengths.
A 200cm long board 12cm wide and 2cm thick board is technically 2 long, 120 wide and 20 thick.
But personally i use mm for everything for practical reasons to avoid confusion and error with commas, and my sketchup is set to mm so i am not slowed by commas.
You rarely work under a mm in woodworking, but when making something that needs to fit exactly in a given dimension you can see on the ruler weather t is in between the mm marks, or closer to one of the two marks, thus you can technically work down do 1/3rd of a mm with the eye
 
In the UK nearly all tradesmen use metric now. The older ones though will use both imperial and metric including myself.

All measuring tapes sold here still have Metric and imperial measurments marked onto the tape. Imperial measurement was started in the UK and is still in use.

I agree with the other comments on here regarding the fact that less than 1mm measurment in wood is not practical in day to day construction or manufacturing.

If I need to work in less than 1mm accuracy to check material width or saw kerfs etc I use a steel rule as tape measures are not marked less than 1mm.
So in reality imperial is still used widely in the UK but it seems only for the older generation who all learnt measurements in Imperial.
Especially with older clients they always seem to discuss measurments in imperial and I am happy not to confuse them trying to preach metric and let them carry on!.
I have taught imperial and metric to all the apprentices that have worked with me over the years so they are competant when faced with questions or sketches in imperial.
I do believe it will eventually be replaced in the UK and I think it will largely happen when metric only tapes are sold widely. Metric only tapes are sold extensively in mainland Europe but I have yet to see them available here. I think  their introduction  would affect how people use units of measure. Just as the change from using dividers and dasiy wheel geometry to imperial tapes affected how tradesmen work.
 
Wooden Lungs said:
In the UK nearly all tradesmen use metric now. The older ones though will use both imperial and metric including myself.

All measuring tapes sold here still have Metric and imperial measurments marked onto the tape. Imperial measurement was started in the UK and is still in use.

I agree with the other comments on here regarding the fact that less than 1mm measurment in wood is not practical in day to day construction or manufacturing.

If I need to work in less than 1mm accuracy to check material width or saw kerfs etc I use a steel rule as tape measures are not marked less than 1mm.
So in reality imperial is still used widely in the UK but it seems only for the older generation who all learnt measurements in Imperial.
Especially with older clients they always seem to discuss measurments in imperial and I am happy not to confuse them trying to preach metric and let them carry on!.
I have taught imperial and metric to all the apprentices that have worked with me over the years so they are competant when faced with questions or sketches in imperial.
I do believe it will eventually be replaced in the UK and I think it will largely happen when metric only tapes are sold widely. Metric only tapes are sold extensively in mainland Europe but I have yet to see them available here. I think  their introduction  would affect how people use units of measure. Just as the change from using dividers and dasiy wheel geometry to imperial tapes affected how tradesmen work.

I have couple metric tapes only.  

I like them for one reason only and that is because you can use your tape from either direction to measure from in awkward places which you can't do with a hyprid tape metric/imperial.    

Saying that I hate them!!!!

I am young but I use metric and imperial because I find my self getting stuck with just a metric tape when I'm given just imperial measurements.

I also use both imperial and metric because I often just pick the easiest number to remember on my tape.     Some times I can measure stuff up and some off it would be in metric and some of it in imperial.

Jmb
 
Even if you are using a thin 0.5mm pencil you can't really mark much less than a millimetre on wood with the grain undulation pulling the pencil this way or that or snapping the lead I don't really see the point of sub-millimetre scales. Most of the time I'm using a Lyra Pica Dry hole marker for my marking needs with a 2.8mm thick lead so
 
If you want more accuracy than a pencil provides you can use a knife-line. Dovetailing, for example.
 
I use this;
measur_trule_pic3_zoom.jpg

but rarely marks anything besides full and half mm.
 
In woodworking you rarely need something less than one whole milliliter.  There are few factors:
- Measure errors. (Positioning ruler or tape, eye error, line error. e.t.c.) Tape's end play error is more than 0.5 mm.
- In woodworking you often do relative measurements instead of "precise dimensions". For example dovetail joints, mortise and tenons etc. 

In metric you usually work with whole numbers, and math is much more easier and convenient.  The problems will pop out with exact imperial to metric conversions. For 12" use 300mm instead of 304.8mm or 305mm. 

Metalworking and machinery is different, but it's different story.
 
Like jmb i use both, always will. Doors and such are imperial sizes normally so i use that
 
I use this one from Starrett and a utility knife. Don't need it more accurate than that.

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Kristian said:
I use this one from Starrett and a utility knife. Don't need it more accurate than that.

[attachimg=#]

So I have to admit that i looked at the metric starret rule I got awhile back and noticed that the backside has 1/2 mm markings.

In my defense, I'm right handed and never use it on that side.....and very busy..... :-)
 
I have an old Bridgeport mill I use to mill steel and aluminum. I learned on it and I now use for my woodworking how to sneak up on an accurate measurement. I don't care if I use metric or imperial it all works the same. There's something I like about the tolerances of metric threads, bolts and nuts. I watch Norm a lot on TOH and New Yankee Workshop and he uses terms like 1 1/2" strong. That means he goes to the beginning or end of a line on the scale. I'm also impressed with tools like the Bridge City Toolworks Kerfmaster, even though I don't own one yet. It works by adjusting it to the size of material and transferring that setting to the tool you are using. Paul Marcel has a video about it.
Gary
 
Personally I find metric easier to work in, which almost sounds sacreligious as an American.... its just much easier and faster to think with a base-10 system.

At least as far as casework, joinery, and furniture are concerned I use metric. When I'm on the jobsite its usually imperial.

-Ian
 
fritter63 said:
Kristian said:
I use this one from Starrett and a utility knife. Don't need it more accurate than that.

[attachimg=#]

So I have to admit that i looked at the metric starret rule I got awhile back and noticed that the backside has 1/2 mm markings.

In my defense, I'm right handed and never use it on that side.....and very busy..... :-)

[thumbs up]
 
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