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Math genius needed, geometry
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Cooler Offline
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#32
04-03-2019, 08:01 AM (This post was last modified: 04-03-2019, 08:06 AM by Cooler.)
Is there any way to calculate the angles for this star?  I'd like to make a large one for indoor use out of 3/4" MDF using just glue to assemble it.  I was good at geometry in high school but it was nearly 60 years ago and this is pretty complex.  I can figure out the angles for the points and interior corners of the star (as if it were a flat piece).

But how to figure the angles for the 3D depth?

It seems like a pretty easy project once the angles are finalized.  Just cut, glue and tape (for clamping), and then paint.

[Image: generous.jpg]

I can easily make one of these, but it is not what I want.  And I want the star to cover a large area of the wall about 36" across.

[Image: il_340x270.1442743226_m8rm.jpg]
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mad_planter Offline
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#33
04-03-2019, 08:14 AM (This post was last modified: 04-03-2019, 08:15 AM by mad_planter.)
(04-03-2019, 08:01 AM)Cooler Wrote: Is there any way to calculate the angles for this star?  I'd like to make a large one for indoor use out of 3/4" MDF using just glue to assemble it.  I was good at geometry in high school but it was nearly 60 years ago and this is pretty complex.  I can figure out the angles for the points and interior corners of the star (as if it were a flat piece).

But how to figure the angles for the 3D depth?

It seems like a pretty easy project once the angles are finalized.  Just cut, glue and tape (for clamping), and then paint.

http://lmgtfy.com/?q=calculate+angles+for+3d+star

this site has a xls file to calculate them:
https://www.lumberjocks.com/Aggie69/blog/33374
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Phil Thien Offline
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#34
04-03-2019, 08:49 AM
Draw it in SketchUp and measure the angles.
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Roly Offline
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#35
04-03-2019, 09:16 AM
Will also need what is the depth to figure the compound miters . Roly
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FS7 Offline
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#36
04-03-2019, 10:21 AM (This post was last modified: 04-03-2019, 02:28 PM by FS7.)
There should not be any compound miters. You might be overthinking it.

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Arlin Eastman Offline
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#37
04-03-2019, 11:12 AM (This post was last modified: 04-03-2019, 11:14 AM by Arlin Eastman.)
I am pretty sure since I do wood turning it goes all by 360 degrees.

You have 5 points with 2 sides which = ten sides

So 360/10=36 degrees each side
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DaveR1 Offline
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#38
04-03-2019, 11:32 AM
Like Phil, I'd model it in SketchUp to get the angles. Precise without calculations.
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Handplanesandmore Offline
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#39
04-04-2019, 04:16 PM
News to me that these days, every woodworker uses Sketchup, or knows how to use it!
Uhoh

Simon
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Cooler Offline
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#40
04-03-2019, 11:42 AM
Thanks for the video links.  I think I have enough to start figuring out the angles.  I will make a small one to test my math, then the large one.  Should be fun.
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Admiral Offline
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#41
04-04-2019, 06:01 PM
(04-03-2019, 11:42 AM)Cooler Wrote: Thanks for the video links.  I think I have enough to start figuring out the angles.  I will make a small one to test my math, then the large one.  Should be fun.

That looks like a great project.  I'm math challenged, so please post the result, and the measurements, when you are done.  I'd love to make one.
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