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Pat, I am not sure if I am understanding the question, the parallel to degrees is catching me up a bit. Would you be able to do a napkin drawing or something and post it here?

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Pat,

 

Not aware of any calculartor but any simple CAD program such as Sketchup will let you draw it out create the angle and measure easily. Maybe the easiest way, ath least that I can think of. That said, take a piece of paper, wood etc. draw a straight line across and then add the angle you want. Measure the rise from the first straight line drawn and add that to your board length.Hope this makes sense.

Edited by sreilly24590

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If you guys are talking about a triangle calculator there are many out there.

https://www.triangle-calculator.com/

https://www.mathwarehouse.com/triangle-calculator/online.php

 

But I have a feeling it is something different you need Pat.

 

@sreilly24590, I am still having a hard time visualizing what Pat needs, sounds like you have a bead on it though, can you help me understand?

@Pat Meeuwissen, it's not your explanation, it's me for sure, visualizing things like this had never been my strong point.

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My take is he needs a board overall length that allows the angle he needs so he needs the overall length. If it has a angle cut at both ends it's a matter off finding the overall length at accommodate the angle(s) and still be long enough. If there is an angle cut on both ends the procedure needs to be done at each end to see what additional length is needed. Let's say he has a board 5' long and needs that board to have a 22 degree angle cut at each end. You'll need a board that is longer than 5' but to see how much more you need to see how much the angle cuts add to the overall length. Drawing this out will allow the length tobe determined. Either draw it out on the board but you have to assume that the board doesn't exist yet so draw it out on paper and measure the additional length and add to the overall length.

 

Have some jet lag but I think this is what he's doing or wants to do. This is where using something like Sketchup really comes in handy allowing you to draw to scale and then make actual measurements and if you don't know the actual angle it will help you determine that as well. I'm more comfortable with AutoCAD but Sketchup is free and will easily do the job and more with a bit of education from videos and a few good books based on woodworking uses.

Edited by sreilly24590

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24 minutes ago, sreilly24590 said:

My take is he needs a board overall length that allows the angle he needs so he needs the overall length. If it has a angle cut at both ends it's a matter off finding the overall length at accommodate the angle(s) and still be long enough. If there is an angle cut on both ends the procedure needs to be done at each end to see what additional length is needed. Let's say he has a board 5' long and needs that board to have a 22 degree angle cut at each end. You'll need a board that is longer than 5' but to see how much more you need to see how much the angle cuts add to the overall length. Drawing this out will allow the length tobe determined. Either draw it out on the board but you have to assume that the board doesn't exist yet so draw it out on paper and measure the additional length and add to the overall length.

 

Have some jet lag but I think this is what he's doing or wants to do. This is where using something like Sketchup really comes in handy allowing you to draw to scale and then make actual measurements and if you don't know the actual angle it will help you determine that as well. I'm more comfortable with AutoCAD but Sketchup is free and will easily do the job and more with a bit of education from videos and a few good books based on woodworking uses.

Thank you very much!

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There is a down and dirty way to do this, prop the board up at the angel you want, then lay another board or small straight piece of anything on the table next to the end that is resting on the table, and scribe a line on the long grain edge that resting on the table. And you'll have your angle drawn directly on the long grain edge of the board. Take the board to the table saw and set the blade to the line you scribed.

That's a field fit framers trick. :)

 

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Here you go Pat.

Here is a link I used for an online right angle triangle calculator. https://www.mathportal.org/calculators/plane-geometry-calculators/right-triangle-calculator.php

I just treated your project like a right angle triangle, so just imagine your isosceles triangle as a right triangle, by seeing only half of your triangle. So with that,

Using the link I gave you.

We have a few givens you provided that we plug into the online calculator.

 

  1. a = the height of your triangle 35"
  2. B = half the angle of your triangle 15°
  3. I divided your angle in half to create a right angle triangle, so half of 30° equals 15° degrees.
  4. I plugged those values into the online calculator and selected the value of "c" which is the hypotenuse of your triangle, or the long legs, click on "Calculate Selected" and you'll see your "c" value at the top of the screen which is 36.235 when converted equals 36 13/64"
  5. You'll also want to know the base of your triangle, now select the "b" value to be calculated and click on "Calculate Selected" again.
  6. Your "b" value is 9.378 when converted equals 9 3/8"
  7. Now we must multiply by two your "b" value of 9 3/8" to come up with your base. Did you need your base length to create this shape in the shop? No, but it's good to have for planning etc.
  8. Now, to come up with your end cut angle for your table saw blade to be set, you simply divide your desired angle of 30° in half and you get 15°, so set your blade tilt at 15° for your ends, or your miter saw, whatever you may be using.

 

I hope I am on the right track of what you needed Pat, if not, set me straight and I'll head back to the drawing board. :)

 

IMG_20190510_161427.jpg

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3 hours ago, Pat Meeuwissen said:

John, this is perfect a way for ME to do it in the future. I see now that it is just two triangles side by side. 

Very much appreciated. 

Pat

Glad it works for ya Pat, now we gotta ask, what the heck ya building?

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Easy peasy.  The math function is "tangent".  If you google tangent, it comes up with an input screen.  You have to fiddle a bit to get the input value to "degrees", then you input 20, 30, whatever angle you want, and the answer comes out as a number.  If you multiply that number by the length of the board (or a line on the board), you get the vertical dimension that will result in the angle you input.  If you do it for a lot of different angles, you might make a little table of tangent values between 15 and 35 degrees so you don't have to google it (and convert input from the default "radian" measurement) all the time.

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And after all that Pat, remember, these numbers are only guides, the reality is that these accurate dimensions rarely work in real life when you start cutting your boards etc, so you'll have to fudge things a bit, take a little off here, and there, to get what you really want, but the values are a great jumping off point to shoot for.

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On 5/11/2019 at 9:01 AM, John Morris said:

Glad it works for ya Pat, now we gotta ask, what the heck ya building?

John, I'm making a version of the Paulk workbench to work out side in my driveway. Going to install t trak in the top and add a pipe clamp on the end to use as a vise with that. No dogholes like this but will make the cutouts for the tools underneath. My table saw is right in my garage so this will be more like an assembly table. Low ceiling in the basement limits projects during the winter months. The main reason I asked the question was to learn how to simply calculate the angle cuts myself.spacer.png

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On 5/11/2019 at 9:46 PM, FlGatorwood said:

Gee, I wish I had done better in algebra.  :Laughing:

Trig.  You know alpha and b, now you want to know c.  Hint: looks like you want cos function.   It's on your electronic devices.

Or just get yourself some resin paper, straight edge, and protractor and draw it out full sized and measure.

 

image.png.25b415cbcce9b757cf6352b4eaea45c9.png

Edited by kmealy

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7 hours ago, kmealy said:

Trig.  You know alpha and b, now you want to know c.  Hint: looks like you want cos function.   It's on your electronic devices.

Or just get yourself some resin paper, straight edge, and protractor and draw it out full sized and measure.

 

image.png.25b415cbcce9b757cf6352b4eaea45c9.png

Huuuh?  I remember something about sin and cos and tan but the rest of it leaves me in the dust.  Is this modern math?:D

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