Simple measuring trick

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Simple measuring trick

Postby tonyj » Fri Aug 25, 2006 10:13 am

Masking tape!

Not working to plans and building by eye has its drawbacks, one of which is having to guess with measurements.

A steel tape sucks for trying to measure around a radius, especially when there is nobody to hold the other end. (Jake could do it, but he gets the tape all slobbery.)

Last weekend, after measuring the door opening for trim for the umpteenth time and getting the umpteenth different measurement (and forgetting which block of wood I had scribbled the measurement on), the light went on.

I carefully taped the inside of the door opening (at halfway point) with masking tape making sure not to stretch the tape, marked my beginning and end points, carefully pealed the tape off and taped it to the edge of the workbench, overlapping the corner with one of the marks. Pulled out the ole trusty steel tape and measured from the corner of the workbench to the mark on the tape. Voila! Remember, this is a rough measurement cause the tape might have stretched, but it gets the measurement pretty damn close. This method would have also worked for marking spar locations on the wall. Do it in reverse. Tape on the workbench, mark the spar locations, peal the tape an put in on the edge of the wall and transfer the marks. This method when done with a stick of wood is called "story boarding."

I love to find ways to cheat on measuring!
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tony
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Postby Elumia » Fri Aug 25, 2006 10:28 am

Another trick:

For accurate inside measurement, measure from one corner 10", make a mark, measure from the other corner to your mark - make sure to add 10"!!!


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Postby madjack » Fri Aug 25, 2006 10:57 am

Tony, if you can find an old fashioned yard stick, they work very well for measuring around radius's...we have a couple in the shop and they are invaluable for all sorts of measuring and using as a straight edge for layouts...
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Postby tonyj » Fri Aug 25, 2006 11:07 am

madjack wrote:Tony, if you can find an old fashioned yard stick, they work very well for measuring around radius's...we have a couple in the shop and they are invaluable for all sorts of measuring and using as a straight edge for layouts...
madjack 8)


The only yardsticks I could find are metric and I ain't building no stinkin' foreign teardrop!

I swear this is a true story. Had a friend that hung wallpaper and she hired a new helper that barely got out of high school. When the new hire asked how to lay out a certain role to get the pattern match, my friend said, "First cut a yard and then lay out next to what is on the wall." The helper went looking for a lawnmower.

I swear it is true.
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Just when you think a problem is solved, an uglier result replaces it.

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Postby jmtk » Fri Aug 25, 2006 2:09 pm

I used my 60" sewing measuring tape. You now, the kind that tailors and seamstresses always have draped around their necks for measuring people's waists and such. Worked great for measuring around curved things because that's what it's designed to do. It's still sitting in my toolbox. So guys, go raid your wife's sewing kit! Or for you Renaissance men like Doug, go raid your own sewing kit!

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Postby tonyj » Fri Aug 25, 2006 2:12 pm

jmtk wrote:I used my 60" sewing measuring tape. You now, the kind that tailors and seamstresses always have draped around their necks for measuring people's waists and such. Worked great for measuring around curved things because that's what it's designed to do. It's still sitting in my toolbox. So guys, go raid your wife's sewing kit! Or for you Renaissance men like Doug, go raid your own sewing kit!

Jeanette


I have one sitting on my desk at home, and every time I need it at the shop 60 miles away, I always wonder why I can't remember to pack it. I never use it at home!
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Postby alaska teardrop » Fri Aug 25, 2006 2:16 pm

    Alvin Flexible Curve Rulers can be found at drafting or art supply stores. Handy tool. :thumbsup:
    Some examples on this site.
Northern Lite Traveler design: viewtopic.php?f=27&t=51991
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Postby asianflava » Fri Aug 25, 2006 2:29 pm

jmtk wrote:I used my 60" sewing measuring tape. You now, the kind that tailors and seamstresses always have draped around their necks for measuring people's waists and such.



Ditto! I was going to suggest the same thing. I used the same type of tape when I measured around the curves. We aquired a keychain one that retracts when you push a button on it. The "real" one bugged me because you had to roll it up manually.
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Postby Hamcan » Fri Aug 25, 2006 8:30 pm

Tony, I just gotta chime in here after reading your comment re: "stinkin' foreign teardrop" I have mostly built a foreign teardrop, Classic Finn is building a foreign tear and so are numerous others in Canada, Oz, Britain and there is even that guy [sorry forgot his name] in Estonia. All those places use the metric system and I assume most builders from there are using metric measure although I didn't, our building materials are still feet and inches 'cause of course the U.S. is our biggest market.
I think it's real funny that you folks fought a justifiable revolution to get the foot of King George and the mother country off your neck and now insist on using an obsolete British system of measurement.
Please don't take offense, I am merely pointing at an anomaly I think is funny. Hope you find the humor in it also.

Regards, JG
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Postby Micro469 » Fri Aug 25, 2006 9:16 pm

Hamcan wrote:Tony, I just gotta chime in here after reading your comment re: "stinkin' foreign teardrop" I have mostly built a foreign teardrop, Classic Finn is building a foreign tear and so are numerous others in Canada, Oz, Britain and there is even that guy [sorry forgot his name] in Estonia. All those places use the metric system and I assume most builders from there are using metric measure although I didn't, our building materials are still feet and inches 'cause of course the U.S. is our biggest market.
I think it's real funny that you folks fought a justifiable revolution to get the foot of King George and the mother country off your neck and now insist on using an obsolete British system of measurement.
Please don't take offense, I am merely pointing at an anomaly I think is funny. Hope you find the humor in it also.

Regards, JG



Just because our stinkin government decided to go metric, doesn't mean real honest woodworkers use that sh*t. When I grew up we used inches feet, and yards. Our lumber is still 2x4's and 4x8's. I never could visualize metric... You tell me it's 39 cm long and I wouldn't have a clue. Tell me it's a yard long and I can show you how long it is. The same with temperature..... You say it's 18*C and I don't know weather to put on a jacket or take off my shirt. Tell me it's 78*F out there, and I'm outside having a cool one.
:lol: :lol: :lol:
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Postby kayakrguy » Sat Aug 26, 2006 6:50 am

Tony--

A great tip, thanks! Do you have any similar advice for finding the radius of curves--ones that are already in place? I've run into that problem many times over the years....answer probably involves Trig and I don't have any sine and cosine tables any more <g>!

Jim
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Postby tonyj » Sun Aug 27, 2006 10:31 pm

Hamcan wrote:Tony, I just gotta chime in here after reading your comment re: "stinkin' foreign teardrop" I have mostly built a foreign teardrop, Classic Finn is building a foreign tear and so are numerous others in Canada, Oz, Britain and there is even that guy [sorry forgot his name] in Estonia. All those places use the metric system and I assume most builders from there are using metric measure although I didn't, our building materials are still feet and inches 'cause of course the U.S. is our biggest market.
I think it's real funny that you folks fought a justifiable revolution to get the foot of King George and the mother country off your neck and now insist on using an obsolete British system of measurement.
Please don't take offense, I am merely pointing at an anomaly I think is funny. Hope you find the humor in it also.

Regards, JG


Believe me, I meant no disrespect and don't want to start any shooting wars!!

I believe that most of the parts on my build probably are metric (plywood, bolts), that's why I'm always 1/16 inch off! :lol:

America has a different mindset. I'm just glad it is a completely different system. Can you imagine the confusion if we started with an "inch" standard, and then subdivided it into tenths?

And metric does make the division easier. I hate having a measurement like 57-11/16 inches and having to divide it in two. :? And I know there is a tape measure that has the 1/2 measurement across from the regular measurement.

So, I humbly aplogize for slandering the rest of the world, and I give homage to the fine builds created in other measuring hemispheres than mine. So, my next build will be 3.048 meters long. Oh, god! How long is .048 of a meter? :cry:
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Just when you think a problem is solved, an uglier result replaces it.

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Postby tonyj » Sun Aug 27, 2006 11:19 pm

kayakrguy wrote:Tony--

A great tip, thanks! Do you have any similar advice for finding the radius of curves--ones that are already in place? I've run into that problem many times over the years....answer probably involves Trig and I don't have any sine and cosine tables any more <g>!

Jim


If you are trying to figure out the radius on something like an existing door opening, use a framing square and a compass, or another ruler. 1st guess at the radius. If you think it is 5 inches, line up the 5 in mark on the square to the door top and door side. Then, using the compass, or ruler, measure from the perpendicular corner of the square to the inside of the radius at what you guess to be 45 degrees. Keep adjusting the square and the compass until the measurements are the same. Remember, a radius is just a quarter of a circle.

(I know there are trig and geometry terms for all this, but they escape me! That was a long time ago in a galaxy far, far away.)

If you are trying to calculate the measurement of the outside of the radius, and further, the perimeter of the door opening with radius corners, it is just some simple math. The outside measurement of a radius corner is 1/4 the perimeter of a circle. If you have a 5 in radius, your circle would have a diameter of 10. Multiply 10 by pi (3.1412) to get 31.412. Divide that result by 4 to your radius perimeter length of 7.85 (7-27/32).

To calculate the perimeter of the door opening (I'll use 30x36 with 5 in radius corners), add length and width and multiply by 2. Subtract the product of the radius corner measurement multiplied by 8. Add the perimeter of a circle with a 5 in radius.

Step 1: (30+36)=66 mult by 2 = 132
Step 2: (8X5) = 40
132 - 40 = 92.
Step 3: (5 X 2 X 3.1412) = 31.412
92 plus 31.412 = 123.412

The perimeter of the door opening is 123.412 in. (123-13/32).

It's then just basic math to calculate length of whatever number of trim pieces, and use those results to mark midpoints for centers of radius for bending trim. The is the exact method and calculation I used for cutting my trim pieces (except for a tight 4 in radius and different door dimensions.

If this wasn't the answer to your question, a lot of people are going to have their gut feeling confirmed that I am an idiot.

And if someone spots a math error, let me know and I'll correct this post.
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Postby asianflava » Mon Aug 28, 2006 2:12 am

tonyj wrote:America has a different mindset. I'm just glad it is a completely different system. Can you imagine the confusion if we started with an "inch" standard, and then subdivided it into tenths?


I love using that method but mostly with machine work and mechanical stuff. Machinists use that method, which is why micrometers and calipers are divided to .000 of an inch. I have a hard enough of a time keeping up 1/16in tolerances with wood, which is why I resort to my "secondary tolerance" of 1/8in.
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Postby Hamcan » Tue Aug 29, 2006 12:07 am

Tony
I didn't mean any disrespect either and certainly don't want a shooting war, LOL.

I was a surveyor when systems international was introduced into Canada in the late 70's and initially was not very enthusiastic but soon realized that it was far better for survey, fewer mistakes and easier math, however we [Canadians in general] have never fully converted. Most of us are sort of confused when it comes to weights and measures and it seems that very few are fully comfortable with celsius and I know no one that uses it for carpentry unless forced by government contract.

But as an example of the ease of use, your question "what is .048 of a meter" the answer is 48mm since there is 1000mm in a meter. Nothing easier and since we are all used to thinking of aluminum in 1/1000's of a inch as in my tear is covered in .030 or .040 aluminum the transition is actually pretty simple.

However in stead of being out a 1/16 you will be out 1mm instead. That is just in the nature of using wood.

Your gracious apology was not necessary but thanks and keep up the good work whatever system of measurement you choose.

Regards, JG
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