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Thread: Should I learn Metric now? Beginning woodworker help.

  1. #31
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    Quote Originally Posted by roger wiegand View Post
    Not when I need to find a third of a measurement given as "2 ft 6-7/8 inches.
    (Tried. Can't resist the chance to smart off!)

    That's actually pretty easy: 10-7/24". Oh, you wanted the same fractions as on your ruler?

    Seriously, if we measure in fractional inches we're stuck with this problem, but there are alternatives. I've barely scratched the surface of the mathless geometry George Walker & Jim Tolpin teach, (in Hand & Eye, etc & on their blog,) but almost any layout problem can be solved with the right arcs and intersections and *NO* *Math*.

  2. #32
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    Easy math to do in your head just double both numbers until it’s easily divisible by three. If that doesn’t work, raise it from .875 to .876 then divide by three and it is 10.292”.

    I prefer decimal inches and fractional inched for building stuff.
    Last edited by Brian Holcombe; 07-13-2020 at 1:42 PM.
    Bumbling forward into the unknown.

  3. #33
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    I understand that the math isn't hard, and I can still mostly do it without reaching for a pencil (it was really beaten into me as a child) but working in fractions is both more prone to error and (to me) less obvious when an error has been made. Given the choice I use a story stick and simple geometry, doing arithmetic increases the opportunity for error a lot. If I have to use a ruler or tape my brain works better with decimal rather than fractional values. My errors that way tend to be by a factor of 10 and easier to spot.

  4. #34
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    Quote Originally Posted by roger wiegand View Post
    ...10 decimal inches in a foot, but as far as I know there are not, or at least I've never seen such a ruler...
    Decimal foot tapes do exist. That is, they show measurements like 5.7 feet. For instance https://www.ustape.com/catalog/engineers-tapes/. I've also seen 100 ft tapes marked that way.

  5. #35
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    To be honest, as long as you're always using the same measuring device it doesn't matter. Metric IMO is generally much easier, but I grew up with it.

    Then again, I don't like measurement as it tends to just induce errors anyway.
    ~mike

    happy in my mud hut

  6. #36
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    No matter what you do, you will probably need to do a mixed usage because you will need both english and metrix sockets; for example.

    The most important bit is probably that you decide now so that you are certain to invest in tools marked appropriately; for example:


    • tape measures
    • Measuring tape on your table saw
    • chisels (imperial or metrix)


    to name a few!

  7. #37
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    I believe the plywood standards specify standard metric dimensions such as 19, 12, 6 etc which are then sanded...Rod

  8. #38
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    Completely out of curiosity, what is the comparable measure to "board feet" in metric countries? Is wood sold by the "board meter" or some such thing?

  9. #39
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    Quote Originally Posted by David Bassett View Post
    Dividing in half is one thing that works pretty well with fractional inches. (23-11/16 / 2 = 11-16/32 + 11/32 = 11-27/32.)
    Yeah, i've actually been using a combination of this and decimel inches when my brain hurts. Most of what I build is not that critical. I do a combination of rough measuring, then bringing the piece to its final resting place and transfer a mark onto it, or using something as a reference (story stick) to make a repeatable part.

    I've been debating with myself if I can fully get away from Imperial if I switch to Metric or not. Or will I just convert everything I read in metric back into Imperial in my head like I use to do with most Spanish speaking.

    I took 4 years of spanish and whenever I spoke, I would think of it in english, translate in my brain to spanish, then speak it in spanish. The reverse for hearing spanish.

    I was never bilingual because I was never imersed in it. If I imerse myself in Metric, maybe I won't have to convert back to Imperial.

    There's lots of great dialoge on here.

    Trouble with decimel inches, I don't see it as a scale on most fences, and while tape measures do come in Decimel Inches, they're not very common.


    Quote Originally Posted by Jeff Ranck View Post
    It really doesn't matter which system you choose. You can work in either and I'm not one that personally believes one is qualitatively "better" than the other. The best advice I received on the topic was choose a system and stick with it and buy all your tools with the appropriate scale. For example, if you choose metric, then when you buy a set of chisels, buy metric. I echo the advice from Roger to avoid a mixed shop at all costs.
    This is the main reason why i'm asking. Going to be buying some tools in the coming months, Don't want to buy more Imperial if I am going to make the switch. I probably only have a few hundred dollars wrapped up in stuff that I would want to replace.

    Quote Originally Posted by John Stankus View Post
    Precision and accuracy are independent of measuring system.
    Precision is how repeatable your measurement (think how tight of a grouping is on a target).
    Accuracy is how close you are to the "actual" value (think how close you are to the bullseye on a target).
    You can be highly precise and accurate with a story stick with no units at all.

    The inch is actually defined in terms of the metric units. The original inch was defined as three well dried barley corns from the center laid end to end, but is now defined at 25.4 mm exactly. Actually, all the US standard lengths have been based upon metric standards since the middle of the 1800s

    National Bureau of Standards (now NIST) Weights and Measures Standards of the United States- A brief history
    https://www.govinfo.gov/content/pkg/...b586b60735.pdf

    John
    The Inch being 25.4mm is rather funny. Maybe it won't be too hard to make the change afterall.
    thanks for the info about precision/accuracy


    Quote Originally Posted by Andrew Pitonyak View Post
    No matter what you do, you will probably need to do a mixed usage because you will need both english and metrix sockets; for example.

    The most important bit is probably that you decide now so that you are certain to invest in tools marked appropriately; for example:


    • tape measures
    • Measuring tape on your table saw
    • chisels (imperial or metrix)


    to name a few!
    I think I might invest in a Metric tape measure and next project I build, just use that and see how things go. I don't have a ton of router bits, drill bits that I'd need to replace.

    Are dado widths measured in both imperial and metric? Or do you actually make a 1/2" wide dado and then the slightly thinner 1/2" plywood (not actually 1/2" thick) just fit a little loose?

  10. #40
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    Oh, one more question, when i asked about precision and accuracy, what I was getting at, was that 1/32 of an inch is roughly 0.79mm. So if the one camp is measuring things down to 1/32" increments, won't they be more accurate than the camp that measures in 1mm increments, taking out story sticks from the process?

    Example, you can get an incra LS positioner with either 1/32" spacing on the lead screw or 1mm spacing. in 4 inches you have 101 (1mm) Metric units, or 128 (1/32") Imperial units. Do you have more control with the imperial setup here?

    However, I don't know many tape measures that show 1/32" marks past the first foot (guess) and only show 1/16" past this point, but looking at several online, they do show every MM. So in this example, the 1/16" is roughly 1.58mm. So the MM ruler has higher resolution ( i think that's the right word). 1/32" also seems SO SMALL and tight on a measure, maybe 1mm fits nicely between 1/16" and 1/32"?
    Last edited by Jon Steffen; 07-13-2020 at 6:47 PM.

  11. #41
    Jon,

    I think you are over thinking this. I work in Imperial whenever possible because I can easily visualize what 4 inches is. Or 70 inches. Or 5 feet 10 inches. If I were to switch to metric (which will not happen), I would have to learn this all over. I do not see any benefit worth that transition.

    If you can visualize equally well in both systems, it comes down to just preference and possibly somewhat the tools you like. If the tools you prefer come out of Europe, you may want to go metric. It will be easier. If you prefer tools from U. S. suppliers, you may want to use Imperial.

    I can remember 1 inch equals about 25.4 mm. But I do not know that the 6mm cutter in my domino is about 1/4 inch without doing the conversion to inches or looking at it. 6mm doesn't mean anything to me. 1/4 inch does. But it doesn't really impact me to make a conversion like this for his tool.

    I agree completely with the other comments that it does not affect the quality of your work to use either system. Some things are easier in Imperial and others easier in metric but great work is done using both systems. My work has improved from things like using stops instead of trying to cut to marks when possible (makes duplicates much closer to the same). And making parts to fit with other parts already made (to avoid small errors adding up). I am still fairly early in my domino usage but I believe it makes mortise and tenon joints enough easier and quicker it is worth putting up with the metric side of it. But you need a way that works for you to make standard joints like mortise and tenon, rabbets, dados, and probably dovetails. Those things will improve your work. Using metric instead of imperial or vice versa will not by itself improve your skills or results.

  12. #42
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    Quote Originally Posted by Jim Dwight View Post
    Jon,

    I think you are over thinking this. I work in Imperial whenever possible because I can easily visualize what 4 inches is. Or 70 inches. Or 5 feet 10 inches. If I were to switch to metric (which will not happen), I would have to learn this all over. I do not see any benefit worth that transition.

    If you can visualize equally well in both systems, it comes down to just preference and possibly somewhat the tools you like. If the tools you prefer come out of Europe, you may want to go metric. It will be easier. If you prefer tools from U. S. suppliers, you may want to use Imperial.

    I can remember 1 inch equals about 25.4 mm. But I do not know that the 6mm cutter in my domino is about 1/4 inch without doing the conversion to inches or looking at it. 6mm doesn't mean anything to me. 1/4 inch does. But it doesn't really impact me to make a conversion like this for his tool.

    I agree completely with the other comments that it does not affect the quality of your work to use either system. Some things are easier in Imperial and others easier in metric but great work is done using both systems. My work has improved from things like using stops instead of trying to cut to marks when possible (makes duplicates much closer to the same). And making parts to fit with other parts already made (to avoid small errors adding up). I am still fairly early in my domino usage but I believe it makes mortise and tenon joints enough easier and quicker it is worth putting up with the metric side of it. But you need a way that works for you to make standard joints like mortise and tenon, rabbets, dados, and probably dovetails. Those things will improve your work. Using metric instead of imperial or vice versa will not by itself improve your skills or results.
    I'm overthinking it on purpose. There's pros/cons, advantages /disadvantages, opinions on everything. Wood workers thousands of years ago made fantastic things, just trying to figure out which tips the scale for me.

  13. #43
    I used both metric and imperial as a machinist. Imperial was my preference simply because most of our tooling where I worked was imperial, but I had some metric that I used and it worked fine when I needed it. Back then I could do the conversions in my head.

    For woodworking, I guess I always found metric to be kind of clumsy. The mm and cm seem too small, and meters too big. Since furniture is usually human scaled, measurement based on human scale (inches, cubits, feet) seem to have a convenient correlation to what you are making. I know you can do the same in metric and all the metric people will attack this as backwards and simplistic, but it works that way for me. It is possible that if I grew up in metric I would think that imperial was clumsy too.

  14. #44
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    Oh, one more question, when i asked about precision and accuracy, what I was getting at, was that 1/32 of an inch is roughly 0.79mm. So if the one camp is measuring things down to 1/32" increments, won't they be more accurate than the camp that measures in 1mm increments, taking out story sticks from the process?
    Jon, I generally measure to a half mil but the "detail" end of my rules breaks it down further if necessary. While it's good to have a decent metric tape measure for longer needs, woodworking projects benefit greatly from using metal rules for most measuring. Tapes can sometimes be less accurate over their length. (But even rules need to be checked, especially if they are different brands mixed) I have a set of dual scale rules from Lee Valley (Woodcraft also has them), a digital caliper and I retrofitted my Starrett combo square and smaller square with metric rules. BTW, story sticks are a really great way to work with consistency. I also tend to use fixed dimensions for the larger assembly and then measure intermediate components directly off that assembly so that they are exact...no scale needed.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  15. #45
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    Wise advice

    Quote Originally Posted by Rod Sheridan View Post
    I went metric in woodworking decades ago.

    It's easier than fractions, plywood thickness is metric and most of the tooling in the world is metric.

    Designing in metric is far easier, and nobody can tell whether the leg is 50mm or 2" thick. That's the secret, don't convert your design from Imperial to metric.

    Make the legs 50mm thick, plane boards to 20mm thick not 3/4".

    Have fun, it's worth converting.

    Regards, Rod.
    That advice from Rod probably is the key point to get a positive experience on adoption of the metric system coming from imperial one. I knew people.that got frustrated in the process just trying mathematical conversion.

    I live in a "metric" country. I prefer to work with metric only as I do most of the time but I am comfortable to work with decimal inches or even fractional (although it is odd IMO).

    Curiously I made a general inventory check in my router bits today accordingly to their chuck size: 1/8in, 6mm, 1/4in, 8mm (actually my main size), 12mm and 1/2in. Crazy.

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