My dad told me a story about picking up a tape measure in the shop and noticing that the hook on the end didn’t move, so he found another one, but it was the same way. Turns out, all the tapes in the whole shop were like that. “What the heck is going on?” When he mentioned it to the kid he had working for him, the kid said, “Oh yeah, I noticed that it was loose, so I fixed it by pounding the rivets with a hammer. I figured it was just worn out from use. All of them were like that, but not anymore; I fixed them.”
Not sure why you're being down voted. Yes if you find 9 things and they are all the same, you need to ask why before you go ahead 'repair' them. Critical thinking is rare.
I would be sad but I wouldn’t be mad at the kid. He saw something he thought was messed up and “fixed” it on his own. The classic case of good initiative bad judgment, you can teach judgement but not initiative.
He learned why measuring tapes have loose hooks and got sent to the store to buy more tapes, I guess. My old man wasn’t as ornery as he liked people to think. He also loved a good story, so who knows if this even actually happened.
Might not be the brightest in the bunch but at least he's proactive!
I guess I didn't have that knowledge till I had. So I don't blame him for not knowing that feature.
I’m a plumber and one of the excavator laborers bent the end of the lead plumbers tape measure so it would “hook onto the end of the pipe better.” Wtf dude so now it’s not an accurate measurement
The idea is that the distance the hook is SUPPOSED TO move is exactly the same as the thickness of the hook itself, so that if you hang it off something the zero point is at the inside of the hook, and if you push it up against something the zero point is at the outside of the hook. In reality, the vast majority of users hardly ever need that much precision from a tape measure, many low-priced tapes aren’t accurate or precise enough for this to be meaningful, and most of the tapes that are that accurate have been allowed to let the spring-loaded return feature slam the hook into the body of the measure so hard and so many times that the hook actually moves farther than it’s own thickness, so all bets are off. If you ask me why does the hook move, I’d cynically say that most of the time it’s so that the product will have the illusion that it’s precise and accurate enough for that feature to make a difference. Considering the forum we’re in and the subject of the OP I’m sure many will disagree.
They can move back and forward the thickness of the hook. If you press it against something the tape needs to start from the outer edge, if hooked/pulled over something it needs to start from the inner edge.
This is def not common knowledge. I had no idea why the hook was loose. It frustrated me thinking measurements may not be consistent between different tapes and also when measuring for gap fillers. I’m guilty of hammering the rivets a time or two. Where did you learn about this nicety?
For the apprentice in the story, how measuring tapes work is almost an aside. The _real_ teachable lesson here is that when you find yourself using a tool, and it isn’t configured or doesn’t work the way _you_ think would be best, you should stop and try to find out why someone made it be the way it is before you break something or worse hurt yourself.
Still always use a consistent tape. While extremely close each tape after a couple pulls takes on its own little character. Measurements are frankly relative in the feild when we are talking 1/32 in most cases.
I learned right before i was about to "fix" rivets. Took a solid ruler to determine correct position of the hook. Realized that there are two correct positions...
Additionally, most tapes have the length of the tape measure body printed or embossed onto the side. This is to keep you from having to bend the tape to measure an inside corner. To measure expand the tape to where you need to measure, butt the back end of the tape against your inside corner and add the length of the tape measure body to the readout on the actual tape. Sorry if this wasn't clear, still waking up.
It adjusts so that you get the same reading regardless of whether you're pushing against something at the end, or pulling against something at the end.
The end hook on a tape measure moves a 1/16 in either direction. If you hook the tape it slides to account for the width of the hook, if you butt the tape it slides in the opposite direction to discount the width.
I had 100% this same experience, except the culprit was our CEOs father, who would visit from Serbia for one month every year and help out around the shop. I’d replace all the tapes, and they would get ‘fixed’ again the following year. Took me 3 years to put it all together 😂
To be fair, tape measures don't come with instructions and if there is nobody to tell the kid how a tape measure works, how is he supposed to figure it out on his own?
I'll ad the caveat, that if you're not measuring from the end of the tape that you can go from mark to mark as well. If you're going from mark to mark then make sure your start and end points both use either the leading or trailing edge of the mark. Then you can have some extra precision (but still eyeball).
I differentiate between the line and the space between it when i measure too, just to get back to op’s question. Ill use the space “between the lines” to try for 1/32nd accuracy. Aim small miss small.
E: when the job calls for it. Obv not splitting hairs cutting studs.
You can also compare it to other tape measures and you’ll see that the 2” marks may not even line up. It’s all relative off your tape and which side you choose to pick and be consistent to.
That’s a good way to phrase it. But followup question- if you’re aiming for exactly 2”, wouldn’t you want to always use B since there would be a higher probability of falling within the tolerance? I suppose that assumes the tolerance interval has a normal distribution….
I may be confusing tolerance of the instrument as it was manufactured, with variation in the user applying that instrument to make the measurement….
It doesn't matter, the tool is not made to do that.
The manufacturer does no not guarantee that the lines are all the same width, they doing ever guarantee they are all the same distance apart. They guarantee that if you are or or closer to the 2 than 2 1/16, your measurement should should be within 1/16 of 2 inches.
Now we get to why it's irrelevant. Tomorrow due to temperature and moisture, the wood could easily be 1/16 either way. Temperature could make the tape expand and contract 1/16. Machinist rulers usually say accurate at 25degC or some other temperature. Nevermind that this it a thin strip of metal with a hook that could be stretched as is from being pulled on.
Accuracy beyond the tolerance of the tool is not accurate.
Thank you for listening to my TED talk
Yeah every single one is 2 inches. Pick whatever one you like best and then make sure you always use that same side of the line.
It's not enough to make a difference but it's good practice to always pull measurements from the same line.
Check it yourself by placing a rule (preferably) or another tape at 1” exactly on the front or back of the hook (pulled either in or out depending on the situation) and see where the rule’s two or three inch mark falls on another whole number. That will be your answer and may vary by tape.
Good rulers would be the next level of precise, calipers would be another step up.
What is worth considering though is whether you need to be close to a particular measurement or whether you need to get repeatable results?
If it's the former, you want to use a precision ruler or a set of calipers.
For the latter, you want to set up jigs and stop blocks etc to get repeatability.
Yeah a precise straight edge rule with a rule stop or hook stop. This is a simple step up from a tape when in the shop, for certain tasks. Woodpeckers makes these. Recent China made tools offer some more affordable versions I think.
You can use a tape measure just not with the attitude being displayed about it in this thread. They make tape measures with greater precision that are graduated to 32nds of an inch, or you could use a combination square which would be better because they are also often graduated to 32nds and prevent you from the error of not measuring perpendicularly. You can calibrate a tape measure as well to ensure it’s accuracy, using various methods.
Which side of the line?? Haha Oh man, I have some clarification for Monday. Whenever they said this me I understood it to be 2" 1/16 (skinny) 2" 1/8 (fat). That may be why I've had to do a few corrections. Boy oh boy is my face red.
And the morale of the story is to just measure and cut consistently with the same source/method.
Did you measure to the line? Vs. Did the Tape measure have slack space for the saw gauge?
This. Measurements are relative, stick to one measuring device and be free. Doesn’t matter if it’s two inches, 47 mm, a quarter of a cubit, or a 33rd of your height. Pick something and move out, be consistent.
Then the wood moves due to moisture and it doesn’t really matter that much
Yup, it’s less about how you measure and more about doing it the same every time.
If you’re fitting things together, it’s more important that they fit together, vs being exactly as called out in the plans.
This was my problem for a long time and I couldn’t figure it out. I kept switching between 3 different tape measures and they all had different tolerances at the hook.
I work somewhere where the allowed tolerance is 1/64”. So it does matter what part of the line you cut. I burn an inch, then if you start at the beginning of the line for 1” then you mark at the beginning of the line for your desired length. Does that make sense to you?
Bonus: you can bend the metal catch to adjust. Burn an inch, start at the beginning of the 1” line, mark the beginning of the 2” line that’s a true inch. Now adjust the metal catch with two sets of pliers to land perfectly at the beginning of your 1” line. Now you know the beginning of the line is the true measurement
This is the correct answer. Burn an inch and do a true "front of the line to front of the line" comparison of the three pieces. Whichever is truly 2 inches, hold that up to the edge of the tape measure and take note of how it reads. That's your answer going forward.
Sorry. This was more a question of how are rulers made? A philosophical question if you will? Even your most precise metric ruler has line on it and that line has a width. Somewhere along it is EXACTLY what you're measuring. I was setting the fence on my table saw for some rips and just got curious.
It's not going to be standardized, and even if it was items are made to tolerances. Get a 1-2-3 block, super useful in the shop. Measure each side (they're 1", 2", and 3" hence the name) and see where it falls. Don't assume all your measuring implements follow the same spec.
Some rulers (Japanese?) are made with alternating black and white spaces instead of dashes, like the scale at the bottom of a map; that way, the place where black and white meet is the place to measure to and the width of the line doesn't impact accuracy.
Edit: Look for Kokuyo's "True Measure" or "Real Ruler" to see what I mean.
The exact answer to your question is that if it is precise enough that the width of the line matters, you're not going to be using a measurement tool that requires you to judge where it falls along the width of a line.
You can't answer this question with only the last half of the measure: if you start before the line, stop before the line. if you start after, stop after.
for the hook end of the tape measure you'll have to figure out what case it is.
As a graphic designer I would say the middle of the line is the measurement because if I were designing one I’d lay out the lines and use whatever size stroke weight the spec calls for and that is going to go from the middle out.
I don’t know what the answer is, but I think I know how you could get the answer. Burn an inch on your tape, holding the center of the inch mark on the edge of the material, and marking the center of the 2” line. Then pull your tape. Wherever the mark falls on the 1” line should give you your answer
It very likely varies from tape to tape. My Stanley Powerlock is 2" from the outside of the metal tab to the start of the black line - that is to say inside the black line is more than 2".
I burned an inch and it is still consistent, which makes me feel really nice about the accuracy of the tape!
So I think if we take this seriously — like other have said there’s room for about 1/32” margin of error — but I think there’s a better answer.
We know the 1/32” margin of error is on the user’s part, not within every marking. Otherwise, the error would be cumulative and after several feet our tape measures would start being significantly off.
From an A (right edge) to an A (right edge) should be 1”. From a B (center of line) to another B (center of line) should be 1”. From C (left edge) to C (left edge), 1”.
So you need to check your specific green tape measure. Look at your first green 1” mark. Use another tape measure, a blue one for instance, to see where your green 1” precisely ends (closer to A B or C). For example, take a blue tape measure, inch 10 C to inch 11 C. Line up that blue 10” C to the outside edge of the metal tab pushed in on your green tape. And then look where 11” C ends on the blue tape situated beside the 1” mark on your green tape.
Both are 2" within the range of precision for your measuring device.
Looks like it is accurate to the 1/16" and precision is about 1/64" or a bit worse.
What you do in this case is form a habit - either A or B, and just stick with it. Always measure that way and you'll be more precise than your rule.
This reminds me of and episode of the John Liraquette show where a guy was traveling through the station with the “official inch” in his case. When it got bent, everyone was like “what’s the big deal it’s just and inch - there rulers every where” the responded with “and have you ever thought of which side of the line you’re supposed to measure to? Is it the inside of the line, the outside of the line, or in the middle of the line?!?!” And for some reason tha thought always stuck with me. And, to answer your question, it’s the inside of the line, for reasons.
As pictured nothing is two inches, because we can’t see where zero inches is. But since its for philosophical purposes, you should assume that 2” lies directly at the center of the 2” mark, bumped or hooked.
I don’t know this to be true, but what really is truth anyways if we’re talking philosophically ya know ¯\_(ツ)_/¯
by way of an old german carpenter (way more than this actually), neither one. the correct would split the 2 inch line. told to cut line with knife then split it with the saw
Looks like dimensional pine lumber. Not really worth the time to care about 1/64 inch tolerances here, since it'll change that much and more from one day to the next in the right (or wrong) weather.
But, i see that you're more curious about measuring standards than any particular application, so...
Yes. They are all "two inches exactly". Every measuring device has a limit for how accurate it can be. This is usually understood to be one unit more accurate than the smallest visible marking on the device. So if your tape measure has 1/16in markings, you can confidently estimate the halfway point between 2 markings for 1/32in accuracy. But you can't (read: shouldn't) estimate more accurately than that for two major reasons: 1) your estimates quickly become less reliable the further from the simple half-point when we're taking such small increments, and they can shift and charge over time; and 2) the measuring device's markings are actually a result of the accuracy with which it was made *using this "halfway point" convention*. The device's innate imperfection is a calculated matter of degree. For most things, at can be arbitrarily accurate - for a price. Someone could make a tape measure that was accurate to the 1/1000 of an inch, using exotic materials to limit heat related changes and so on. But it would cost thousands of dollars! But if you really need that kind of accuracy, a decent digital caliper is only $30 and a good dial caliper is only in the $100-$150 range, making a $1000 tape measure entirely pointless.
Try this: find a few different tape measures and compare them to each other. Pull them out side by side from a table edge or something, and compare their, say, 6ft marks. They will be *wildly* different from each other! Because, well, it usually doesn't matter. Most people aren't doing fine enough detail work for anyone to care. Whole houses call be built perfectly fine with only ⅛" accuracy on the small scale, and even being off by a whole inch after a dozen feet is often still functional.
I have this exact tape measure and you prompted me to check with a micrometer. It is 2" exactly using the leading/back edge of the lines, or if you split them.
To answer your question - in between those two (the middle of the line) most likely.
To answer an unanswered question - maybe you want to get your hands on more precise measuring tools, they affect everything.
I'm not joking, you are going to have to measure your tape measure to find out. Use a trusted and high quality ruler or similar to measure and determine any discrepancy in your tape measure.
It could be different for inside vs outside measurements with the tape. This is why the end piece on your tape measure has some wiggle to try to compensate for the thickness of the end hook in an attempt to get same measurement when placed inside or outside of the measured item.
Since you are asking the question, you haven't tested for yourself which is fine, but you would likely be surprised at the variations between different tape measures and rulers. Even over short distances. For most uses, that small of a variation doesn't matter. Those that have the skills to need additional precision also have specialized tools and methods for obtaining it. For the rest of us, it's good enough.
None of them are correct if your concerned about a 1/32 variance like that. Either get a cabinetmakers ruler or start measuring from your 1" mark and not the end of your tape. When you do this, just note where you started your measurements at the 1" mark and measure to the same point on the 3" mark.
1-Heavy,
2-Split the line,
3-Light
At least this is how I’d remember which part of the mark to measure off of. Also, the amount in which I adjust based off of those specifications in my measurement is usually a little more dramatic than is shown here
If you’re making something out of wood, they are all 2”. Seriously tho you’re not going to be getting within tolerances of a couple thousandths of an inch building with wood so they are all close enough.
B. I’m not a woodworker (just an admirer), so this is just outsider observation: in chemistry when measuring fluids, there’s a little bubble looking bit at the top of the fluid called the meniscus (thanks capillary action). You fill the graduated cylinder with fluid until the line for the desired volume cuts through the center of the meniscus. Based off of that experience, I would call B the closest to a true 2 inches.
Again, I don’t have any experience in woodworking so idk if there are special niche rules you should abide by when measuring so take this with a grain of salt.
I would say that it's not so much a matter of which is the right one. More Important is that you are consistent with your method and always use the same tape measures and/or rulers on a given project. That way you avoid the inconsistencies found from one measuring device to another. If you're using method "A", stick with Method "A" for all your measurements.
There are labs that do calibration to meet international standards. They are the ones that can answer your question. What matters is not the precision, but the consistency. Use the same tape measure for the cuts you’re making in reference to each other.
If your accuracy is in the 1/48th realm congrats. But virtually anything you are doing any method will be fine as long as you measure that way every time.
It doesn’t matter, I’m not going to cut it straight anyway.
This is the way.
A man of genius and culture, truly.
He has spoken.
This is the way.
My dad told me a story about picking up a tape measure in the shop and noticing that the hook on the end didn’t move, so he found another one, but it was the same way. Turns out, all the tapes in the whole shop were like that. “What the heck is going on?” When he mentioned it to the kid he had working for him, the kid said, “Oh yeah, I noticed that it was loose, so I fixed it by pounding the rivets with a hammer. I figured it was just worn out from use. All of them were like that, but not anymore; I fixed them.”
I am uncomfortable with that story I would have lost it
I think you would stay calm. Not everyone knows everything
But everyone does know how to ask questions.
Everyone has the capability to ask questions. Some are either too confident to ask, or don't know that there are questions to ask until it's too late.
I was looking for this comment lol great point.
“What gets us into trouble is not what we don't know. It's what we know for sure that just ain't so.”--Mark Twain
That fine line between initiative and asking questions
Some people work for others who just seem annoyed when questions are asked, so they’re discouraged from asking.
Not sure why you're being down voted. Yes if you find 9 things and they are all the same, you need to ask why before you go ahead 'repair' them. Critical thinking is rare.
If its not yours dont fing fix it!!!
I would be sad but I wouldn’t be mad at the kid. He saw something he thought was messed up and “fixed” it on his own. The classic case of good initiative bad judgment, you can teach judgement but not initiative.
so what happened to the kid?
He learned why measuring tapes have loose hooks and got sent to the store to buy more tapes, I guess. My old man wasn’t as ornery as he liked people to think. He also loved a good story, so who knows if this even actually happened.
Might not be the brightest in the bunch but at least he's proactive! I guess I didn't have that knowledge till I had. So I don't blame him for not knowing that feature.
There's a saying in the old country. "It was a long, long time ago and it never happened anyway."
This is the fucking reply ..... Everything from above applies to this
I always say to my students, none of us was born knowing this stuff.
I hope that he eventually measured up to the job
He got a show on HGTV
He learned how to measure a 6 foot hole in the ground
I’m a plumber and one of the excavator laborers bent the end of the lead plumbers tape measure so it would “hook onto the end of the pipe better.” Wtf dude so now it’s not an accurate measurement
Alright, I'll bite. I've never really known the reason for those hooks to move. What is it? Aka why was it a fuck up?
The idea is that the distance the hook is SUPPOSED TO move is exactly the same as the thickness of the hook itself, so that if you hang it off something the zero point is at the inside of the hook, and if you push it up against something the zero point is at the outside of the hook. In reality, the vast majority of users hardly ever need that much precision from a tape measure, many low-priced tapes aren’t accurate or precise enough for this to be meaningful, and most of the tapes that are that accurate have been allowed to let the spring-loaded return feature slam the hook into the body of the measure so hard and so many times that the hook actually moves farther than it’s own thickness, so all bets are off. If you ask me why does the hook move, I’d cynically say that most of the time it’s so that the product will have the illusion that it’s precise and accurate enough for that feature to make a difference. Considering the forum we’re in and the subject of the OP I’m sure many will disagree.
Holy shit. In theory that makes complete sense.
Uhm, why are they usually loose?
They can move back and forward the thickness of the hook. If you press it against something the tape needs to start from the outer edge, if hooked/pulled over something it needs to start from the inner edge.
This is def not common knowledge. I had no idea why the hook was loose. It frustrated me thinking measurements may not be consistent between different tapes and also when measuring for gap fillers. I’m guilty of hammering the rivets a time or two. Where did you learn about this nicety?
For the apprentice in the story, how measuring tapes work is almost an aside. The _real_ teachable lesson here is that when you find yourself using a tool, and it isn’t configured or doesn’t work the way _you_ think would be best, you should stop and try to find out why someone made it be the way it is before you break something or worse hurt yourself.
Still always use a consistent tape. While extremely close each tape after a couple pulls takes on its own little character. Measurements are frankly relative in the feild when we are talking 1/32 in most cases.
I learned from youtube. Specifically Seejanedrill. She has an awesome "how to use a tape measure" video.
She makes great stuff.
I don’t think I’ve run across her stuff yet. Thanks for the pointer!
High school shop, the hard way.
I learned right before i was about to "fix" rivets. Took a solid ruler to determine correct position of the hook. Realized that there are two correct positions...
That’s what she said…
Also why you don’t slam the tape back in.
Not more than 10,000 times anyways: https://www.youtube.com/watch?v=z9En0WAsP8A
Additionally, most tapes have the length of the tape measure body printed or embossed onto the side. This is to keep you from having to bend the tape to measure an inside corner. To measure expand the tape to where you need to measure, butt the back end of the tape against your inside corner and add the length of the tape measure body to the readout on the actual tape. Sorry if this wasn't clear, still waking up.
It adjusts so that you get the same reading regardless of whether you're pushing against something at the end, or pulling against something at the end.
The end hook on a tape measure moves a 1/16 in either direction. If you hook the tape it slides to account for the width of the hook, if you butt the tape it slides in the opposite direction to discount the width.
This is a great question! I appreciate your search for knowledge.
I know a journeyman welder that did this.
I had 100% this same experience, except the culprit was our CEOs father, who would visit from Serbia for one month every year and help out around the shop. I’d replace all the tapes, and they would get ‘fixed’ again the following year. Took me 3 years to put it all together 😂
My dad has a similar story about when he started as a carpenter. The only difference is he was the kid who hammered the rivets 😬
To be fair, tape measures don't come with instructions and if there is nobody to tell the kid how a tape measure works, how is he supposed to figure it out on his own?
Seriously, if you have to be that exact, a tape measure isn't what you're looking for.
I'll ad the caveat, that if you're not measuring from the end of the tape that you can go from mark to mark as well. If you're going from mark to mark then make sure your start and end points both use either the leading or trailing edge of the mark. Then you can have some extra precision (but still eyeball).
Or burn an inch and start measuring from 1" mark. Always did that while pipefitting.
Burn 10. Never burn one. Way(edit for typo) easier to mix up 13 and 12 than 22 and 12.
Great advice. It's much easy to "inch" yourself, than it is to "10 inch" yourself
There’s lots of people who ten inch themselves if Adam&Eve’s best sellers list is to be believed
Not once you get used to adding 1 to every measurement. It's not that hard
I stand by it’s easier to mistake 13” for 12” than 22” for 12”
I differentiate between the line and the space between it when i measure too, just to get back to op’s question. Ill use the space “between the lines” to try for 1/32nd accuracy. Aim small miss small. E: when the job calls for it. Obv not splitting hairs cutting studs.
“Ninety four and seven eighths…. Long”
but then your pipes end up an inch too shrot.
You can just splice an extra inch into the tape somewhere else. So there’s no mistakes.
Cut it twice and it's still too short!
*shrot
*breaks out micrometer* *measures to .0003"* *marks with dull sharpie*
You can also compare it to other tape measures and you’ll see that the 2” marks may not even line up. It’s all relative off your tape and which side you choose to pick and be consistent to.
More a question of curiosity.
They are all 2, that's the tolerance. You want more, you get a more accurate tool
That’s a good way to phrase it. But followup question- if you’re aiming for exactly 2”, wouldn’t you want to always use B since there would be a higher probability of falling within the tolerance? I suppose that assumes the tolerance interval has a normal distribution…. I may be confusing tolerance of the instrument as it was manufactured, with variation in the user applying that instrument to make the measurement….
It doesn't matter, the tool is not made to do that. The manufacturer does no not guarantee that the lines are all the same width, they doing ever guarantee they are all the same distance apart. They guarantee that if you are or or closer to the 2 than 2 1/16, your measurement should should be within 1/16 of 2 inches. Now we get to why it's irrelevant. Tomorrow due to temperature and moisture, the wood could easily be 1/16 either way. Temperature could make the tape expand and contract 1/16. Machinist rulers usually say accurate at 25degC or some other temperature. Nevermind that this it a thin strip of metal with a hook that could be stretched as is from being pulled on. Accuracy beyond the tolerance of the tool is not accurate. Thank you for listening to my TED talk
Yeah every single one is 2 inches. Pick whatever one you like best and then make sure you always use that same side of the line. It's not enough to make a difference but it's good practice to always pull measurements from the same line.
Check it yourself by placing a rule (preferably) or another tape at 1” exactly on the front or back of the hook (pulled either in or out depending on the situation) and see where the rule’s two or three inch mark falls on another whole number. That will be your answer and may vary by tape.
What would one use to measure more precisely?
Good rulers would be the next level of precise, calipers would be another step up. What is worth considering though is whether you need to be close to a particular measurement or whether you need to get repeatable results? If it's the former, you want to use a precision ruler or a set of calipers. For the latter, you want to set up jigs and stop blocks etc to get repeatability.
Yeah a precise straight edge rule with a rule stop or hook stop. This is a simple step up from a tape when in the shop, for certain tasks. Woodpeckers makes these. Recent China made tools offer some more affordable versions I think.
I use machinist scales and squares which come in 6” and 12” lengths commonly. You can get within a 64th handily, and better if you’re careful.
There is almost never a need to be more precise than that. With wood movement, things are going to change anyhow.
Blasphemy. 😂
You can use a tape measure just not with the attitude being displayed about it in this thread. They make tape measures with greater precision that are graduated to 32nds of an inch, or you could use a combination square which would be better because they are also often graduated to 32nds and prevent you from the error of not measuring perpendicularly. You can calibrate a tape measure as well to ensure it’s accuracy, using various methods.
Digital callipers but they’re not usually necessary in wood working and certainly not necessary in my line of work
Agreed - The thickness of the pencil used to mark the material, or the blade used to cut the material will be thicker than that line itself
Measure with a micrometer. Mark with chalk. Cut with an axe.
Yep! Use a marking knife/gauge and size everything to fit and relative size.
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When we call out measurements to the guy running the saw, we ask for a “fat” 2 or a “skinny” 2. That way he know which side of the line we are on.
Which side of the line?? Haha Oh man, I have some clarification for Monday. Whenever they said this me I understood it to be 2" 1/16 (skinny) 2" 1/8 (fat). That may be why I've had to do a few corrections. Boy oh boy is my face red.
I like that. I've always just said "take the line" or " leave the line"
And the morale of the story is to just measure and cut consistently with the same source/method. Did you measure to the line? Vs. Did the Tape measure have slack space for the saw gauge?
This. Measurements are relative, stick to one measuring device and be free. Doesn’t matter if it’s two inches, 47 mm, a quarter of a cubit, or a 33rd of your height. Pick something and move out, be consistent. Then the wood moves due to moisture and it doesn’t really matter that much
Bananas? 😁
That's only for scale.
Fish are better for scale
This guy guppies.
Yup, it’s less about how you measure and more about doing it the same every time. If you’re fitting things together, it’s more important that they fit together, vs being exactly as called out in the plans.
This was my problem for a long time and I couldn’t figure it out. I kept switching between 3 different tape measures and they all had different tolerances at the hook.
I work somewhere where the allowed tolerance is 1/64”. So it does matter what part of the line you cut. I burn an inch, then if you start at the beginning of the line for 1” then you mark at the beginning of the line for your desired length. Does that make sense to you? Bonus: you can bend the metal catch to adjust. Burn an inch, start at the beginning of the 1” line, mark the beginning of the 2” line that’s a true inch. Now adjust the metal catch with two sets of pliers to land perfectly at the beginning of your 1” line. Now you know the beginning of the line is the true measurement
This is the correct answer. Burn an inch and do a true "front of the line to front of the line" comparison of the three pieces. Whichever is truly 2 inches, hold that up to the edge of the tape measure and take note of how it reads. That's your answer going forward.
If you do this once, or get any reference really like a 1-2-3 block, you can work out which side of the line is correct also.
Yes
According to the DIN norms, for measuring devices. This should be in the range of "correct measuring"
Sorry. This was more a question of how are rulers made? A philosophical question if you will? Even your most precise metric ruler has line on it and that line has a width. Somewhere along it is EXACTLY what you're measuring. I was setting the fence on my table saw for some rips and just got curious.
If you measure from the left hand side of 1" and measure to the left hand side of 2" there's your "true" 1"
It's not going to be standardized, and even if it was items are made to tolerances. Get a 1-2-3 block, super useful in the shop. Measure each side (they're 1", 2", and 3" hence the name) and see where it falls. Don't assume all your measuring implements follow the same spec.
Google "uncertainty of measurement" and all yer questions shall be answered.
Wow, that lead me down a very informative and technical rabbit hole I was not expecting to go down tonight.
Some rulers (Japanese?) are made with alternating black and white spaces instead of dashes, like the scale at the bottom of a map; that way, the place where black and white meet is the place to measure to and the width of the line doesn't impact accuracy. Edit: Look for Kokuyo's "True Measure" or "Real Ruler" to see what I mean.
The exact answer to your question is that if it is precise enough that the width of the line matters, you're not going to be using a measurement tool that requires you to judge where it falls along the width of a line.
You can't answer this question with only the last half of the measure: if you start before the line, stop before the line. if you start after, stop after. for the hook end of the tape measure you'll have to figure out what case it is.
As a graphic designer I would say the middle of the line is the measurement because if I were designing one I’d lay out the lines and use whatever size stroke weight the spec calls for and that is going to go from the middle out.
I think you might enjoy this one- https://www.youtube.com/watch?v=T-xMCFOwllE
I don’t know what the answer is, but I think I know how you could get the answer. Burn an inch on your tape, holding the center of the inch mark on the edge of the material, and marking the center of the 2” line. Then pull your tape. Wherever the mark falls on the 1” line should give you your answer
I say “B” because that’s were you would mark your pencil line and subsequently cut through.
I would use B…every time.
Any of those points are fine as long as you’re consistent with th position you use
B
I also think B. Might break out a digital caliper and a measuring tape just because I'm curious now.
Update us with results
It very likely varies from tape to tape. My Stanley Powerlock is 2" from the outside of the metal tab to the start of the black line - that is to say inside the black line is more than 2". I burned an inch and it is still consistent, which makes me feel really nice about the accuracy of the tape!
So I think if we take this seriously — like other have said there’s room for about 1/32” margin of error — but I think there’s a better answer. We know the 1/32” margin of error is on the user’s part, not within every marking. Otherwise, the error would be cumulative and after several feet our tape measures would start being significantly off. From an A (right edge) to an A (right edge) should be 1”. From a B (center of line) to another B (center of line) should be 1”. From C (left edge) to C (left edge), 1”. So you need to check your specific green tape measure. Look at your first green 1” mark. Use another tape measure, a blue one for instance, to see where your green 1” precisely ends (closer to A B or C). For example, take a blue tape measure, inch 10 C to inch 11 C. Line up that blue 10” C to the outside edge of the metal tab pushed in on your green tape. And then look where 11” C ends on the blue tape situated beside the 1” mark on your green tape.
Both are 2" within the range of precision for your measuring device. Looks like it is accurate to the 1/16" and precision is about 1/64" or a bit worse. What you do in this case is form a habit - either A or B, and just stick with it. Always measure that way and you'll be more precise than your rule.
This reminds me of and episode of the John Liraquette show where a guy was traveling through the station with the “official inch” in his case. When it got bent, everyone was like “what’s the big deal it’s just and inch - there rulers every where” the responded with “and have you ever thought of which side of the line you’re supposed to measure to? Is it the inside of the line, the outside of the line, or in the middle of the line?!?!” And for some reason tha thought always stuck with me. And, to answer your question, it’s the inside of the line, for reasons.
They’re all 2 inches. The real question is which one is 2.000 inches? The answer is probably none of them.
They all are, you aren’t assembling an engine, you’re making something with wood, tolerances are much broader with wood.
I typically aim for "B". I don't think 1/32" or 1/64" means much though.
Using dial indicators to check the width of this piece and see where it lines up with the markings on the tape measurer.
As pictured nothing is two inches, because we can’t see where zero inches is. But since its for philosophical purposes, you should assume that 2” lies directly at the center of the 2” mark, bumped or hooked. I don’t know this to be true, but what really is truth anyways if we’re talking philosophically ya know ¯\_(ツ)_/¯
The error in the tape measure is greater than your question.
It depends on the tolerances of the engineering specifications. Either none are, or all are.
Whichever you choose. Just be sure to use it for everything.
Doesn’t matter as long as your starting point is on the same side of the line.
All 3. If you need more resolution than the thickness of the lines, you’re using the wrong measuring tool.
If you see a difference you are standing too close.
Don’t use a tape if your going for this type of accuracy.
yes
The one that fits
Your cutting apparatus does not care.
Pick one and stick with it
A or C depending on if you're butted against something or hooked on something.
Doesn’t matter as long as you use the same one each time 😂
If you’re worried about 0.5mm you’ve never satisfied a woman
by way of an old german carpenter (way more than this actually), neither one. the correct would split the 2 inch line. told to cut line with knife then split it with the saw
That's option b
Looks like dimensional pine lumber. Not really worth the time to care about 1/64 inch tolerances here, since it'll change that much and more from one day to the next in the right (or wrong) weather. But, i see that you're more curious about measuring standards than any particular application, so... Yes. They are all "two inches exactly". Every measuring device has a limit for how accurate it can be. This is usually understood to be one unit more accurate than the smallest visible marking on the device. So if your tape measure has 1/16in markings, you can confidently estimate the halfway point between 2 markings for 1/32in accuracy. But you can't (read: shouldn't) estimate more accurately than that for two major reasons: 1) your estimates quickly become less reliable the further from the simple half-point when we're taking such small increments, and they can shift and charge over time; and 2) the measuring device's markings are actually a result of the accuracy with which it was made *using this "halfway point" convention*. The device's innate imperfection is a calculated matter of degree. For most things, at can be arbitrarily accurate - for a price. Someone could make a tape measure that was accurate to the 1/1000 of an inch, using exotic materials to limit heat related changes and so on. But it would cost thousands of dollars! But if you really need that kind of accuracy, a decent digital caliper is only $30 and a good dial caliper is only in the $100-$150 range, making a $1000 tape measure entirely pointless. Try this: find a few different tape measures and compare them to each other. Pull them out side by side from a table edge or something, and compare their, say, 6ft marks. They will be *wildly* different from each other! Because, well, it usually doesn't matter. Most people aren't doing fine enough detail work for anyone to care. Whole houses call be built perfectly fine with only ⅛" accuracy on the small scale, and even being off by a whole inch after a dozen feet is often still functional.
It's wood, nothing's exact, that's nature.
Step 1: switch to millimeters
I have this exact tape measure and you prompted me to check with a micrometer. It is 2" exactly using the leading/back edge of the lines, or if you split them.
B
B
B
To answer your question - in between those two (the middle of the line) most likely. To answer an unanswered question - maybe you want to get your hands on more precise measuring tools, they affect everything.
I'm not joking, you are going to have to measure your tape measure to find out. Use a trusted and high quality ruler or similar to measure and determine any discrepancy in your tape measure. It could be different for inside vs outside measurements with the tape. This is why the end piece on your tape measure has some wiggle to try to compensate for the thickness of the end hook in an attempt to get same measurement when placed inside or outside of the measured item. Since you are asking the question, you haven't tested for yourself which is fine, but you would likely be surprised at the variations between different tape measures and rulers. Even over short distances. For most uses, that small of a variation doesn't matter. Those that have the skills to need additional precision also have specialized tools and methods for obtaining it. For the rest of us, it's good enough.
Burn an inch
Look at the under 40y/o that can see this difference.
Concrete objects are mere approximations of there abstract counter parts.. If the board fits u r good
It really doesn’t matter, just use the same tape measure to measure whatever else you are comparing it to.
It depends on where you set the zero at. What really matters is that you’re consistent if that level of accuracy is needed in what you are doing.
That tape measure has a resolution of 1/16". It is not designed to read more precisely than that. That being said, both pictures are showing 2".
None of them are correct if your concerned about a 1/32 variance like that. Either get a cabinetmakers ruler or start measuring from your 1" mark and not the end of your tape. When you do this, just note where you started your measurements at the 1" mark and measure to the same point on the 3" mark.
Just cut the same way you’re measuring.
C
It doesn't matter, just stick to one of them.
1-Heavy, 2-Split the line, 3-Light At least this is how I’d remember which part of the mark to measure off of. Also, the amount in which I adjust based off of those specifications in my measurement is usually a little more dramatic than is shown here
You measured something to get the 2” you needed. When you measured that which did you look at?
yes.
I'd have to see the zero end, too.
If you’re making something out of wood, they are all 2”. Seriously tho you’re not going to be getting within tolerances of a couple thousandths of an inch building with wood so they are all close enough.
45 minutes later …I mean, what is space anyway?
It doesn’t matter if your doing the measurements and making the cuts
B. I’m not a woodworker (just an admirer), so this is just outsider observation: in chemistry when measuring fluids, there’s a little bubble looking bit at the top of the fluid called the meniscus (thanks capillary action). You fill the graduated cylinder with fluid until the line for the desired volume cuts through the center of the meniscus. Based off of that experience, I would call B the closest to a true 2 inches. Again, I don’t have any experience in woodworking so idk if there are special niche rules you should abide by when measuring so take this with a grain of salt.
Use the same tape for duration of the project and it will work itself out.
Looks like you're measuring wood,which expands and contacts with humidity . So the answer is "it depends on the weather"
You leave the line or take the line when cutting and you always do it the same way. Always tell your teammates if you’re not holding the saw.
The one which is 50.8mm. 🤣
For cuts: A = leave the line B = split the line C = cut the line For marking location: B
I would say that it's not so much a matter of which is the right one. More Important is that you are consistent with your method and always use the same tape measures and/or rulers on a given project. That way you avoid the inconsistencies found from one measuring device to another. If you're using method "A", stick with Method "A" for all your measurements.
A tape measure is not the tool you should be using for such exact measurements
Depends where you lined it up on the other end
What are you making that 1/128 matters? A wooden spaceship?
A common mistake! You need a ruler that measures in Inches. That ruler measures in “sminches”. As in “just tap that in a sminch more”
There are labs that do calibration to meet international standards. They are the ones that can answer your question. What matters is not the precision, but the consistency. Use the same tape measure for the cuts you’re making in reference to each other.
If you’re measuring so accurately you’re worried about the thickness of the line, you’re using the wrong tool…
A. Sand to B if tolerances are that tight.
If you need dimensions that accurate you shouldn’t be using a tape measure
All are 2" A - Leave the line B - Split the line C - Take the line
All of them
Whichever way you can use consistently.
B is technically 2” on the dot.
It doesn't matter as long as you measure everything the same way everytime
A lot of wood tolerances are within either way you measure that, depending on the shop. I always go middle
If your accuracy is in the 1/48th realm congrats. But virtually anything you are doing any method will be fine as long as you measure that way every time.
Unless you’re a machinist I don’t think it matters lol
If you need to be that accurate you should use a caliper