Calculating Compound Angles - Woodworking Talk - Woodworkers Forum
Old 06-29-2020, 12:18 PM Thread Starter
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Calculating Compound Angles

I am rebuilding a bird feeding post that has been destroyed by a 400 pound bear. The vertical piece attaches to a horizontal piece which is 22" long. Perpendicular to this piece is another piece 22" long mounted to this piece to form a 'T' My quest is to make two braces from the outside arms to the vertical post which requires compound angles.

I have a Digital Sears Radial Arm saw so I can make these compound angles. The measurement of 17" is the location I selected to install a stop on the vertical post.

I have tried multiple times to determine these angles but have had very little success. Any help would be appreciated.

The "birdfeeder 1 file has 2 pages.

Regards,
walnut732
Attached Files
 File Type: pdf birdfeeder1.pdf (15.2 KB, 47 views) File Type: pdf birdfeeder2.pdf (15.2 KB, 22 views)

Last edited by walnut732; 06-29-2020 at 12:21 PM.
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Old 06-29-2020, 05:54 PM
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I saw your post earlier today. I looked at both files (they're "safe" according to VirusTotal). I am confused by your drawing and questions, which is why I have not responded. Perhaps others feel the same way.

What is the difference between the two drawings?

Are you asking "What are the simple angles inside the basic triangles?" or is the question more complex than that?
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Old 06-29-2020, 06:49 PM
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confused as well

I too am a bit confused. Can you take a picture or draw something in 3d? Is the rough (real rough) sketch I made anything close to what you are describing?
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Last edited by Dave McCann; 06-29-2020 at 07:07 PM.
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Old 06-30-2020, 09:35 AM Thread Starter
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The bottom drawing is the configuration without the portion to the right of the Blue post.
Thank you for presenting this in 3D.

Regards,
walnut732
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Old 06-30-2020, 09:37 AM Thread Starter
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The additional pieces I want to add attach from the far left arm to the Blue post.
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Old 07-06-2020, 10:52 AM
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Just kind of a guess here of what you're wanting. An actual picture of this birdfeeder might help. I can work out any angles you need (or math in general)
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Old 07-06-2020, 12:14 PM
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Bird Feeder

don'tcha just love it when the Engineers and Architects get together
just to design a simple bird feeder and nobody can figure it out ?

what the customer actually wants:

.

there is no educational alternative to having a front row seat in the School of Hard Knocks.
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Old 07-06-2020, 01:11 PM
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Quote:
Originally Posted by John Smith_inFL View Post
don'tcha just love it when the Engineers and Architects get together
just to design a simple bird feeder and nobody can figure it out ?

what the customer actually wants:
Attachment 391987

.
Please excuse my drawing. I just started 3 days ago with sketch up and am surprised I even got this far.

I realize the horizontal piece which attaches to the post should be flush, just ignore this excess material. As I see it, the compound angels needed for the desired bracing would be dependent not only on the lengths of the horizontal pieces but also dependent on which surface each end of the brace is designed to mate up with.

Once that is determined, I'll leave it up to the math wizards. My only input is to try and clarify some of the data needed.

Hope the drawing helps.
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Old 07-06-2020, 01:24 PM
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Lol oh ok! Hey I was a metal fabricator in the army and trying to take design ideas from my chief was very challenging. It made sense to him, but the problem was only he could decipher his plan!

What's the dimensions of the pieces? I need to know the length of the top of the T (green line) to determine the length and angles of B (brace). And the 17" measurement, is that the red or the blue line?
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Old 07-06-2020, 02:20 PM
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Quote:
Originally Posted by phaelax View Post
Lol oh ok! Hey I was a metal fabricator in the army and trying to take design ideas from my chief was very challenging. It made sense to him, but the problem was only he could decipher his plan!

What's the dimensions of the pieces? I need to know the length of the top of the T (green line) to determine the length and angles of B (brace). And the 17" measurement, is that the red or the blue line?
Just to further clarify the (A) (B) (C) and (D) are the labels I gave each surface. NOT a label for the brace itself. Surfaces (A) and (C) are visible in the drawing. Surfaces (B) and (D) are hidden. Surface (B) is the underside of the horizontal piece. Surface (D) is the hidden face of the post towards the horizontal piece.

The angels for a brace running from (A) to (C) would be different than from (A) to (D) and so on.
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Old 07-06-2020, 02:38 PM
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for Walnut732:
if you are "rebuilding" the project, don't you have enough
of the remnants that you can just copy everything from ?
and photos of what you do have left would be nice to see.
(just thinking out loud here)

.

there is no educational alternative to having a front row seat in the School of Hard Knocks.
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Old 07-06-2020, 02:49 PM
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Oh, there's two braces. I was thinking just one in the middle. So these braces lean in two directions, in towards the center post and then also towards the faces of C and D. But you're right, we need further info to determine the angles.
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Old 07-06-2020, 05:54 PM
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Well this just popped up on my facebook this evening.
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Old 07-06-2020, 07:39 PM
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Quote:
Originally Posted by phaelax View Post
Well this just popped up on my facebook this evening.
Are these the braces everyone is talking about?
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Old 07-07-2020, 10:58 AM Thread Starter
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Thank you all for your suggestions and comments. Because of this project I forced myself to learn Sketchup. After spending about 4 hours with the on-line version I was able to get an idea of the angles needed to make this brace part. The picture of the Bear is very close to home since the original feeder was made of schedule 40 pipe which he bent as if it were macaroni. After straightening this pipe about 8 times AI opted to make it out of wood for easy replacement. As the feeder became heavier the arms started to warp, this is the reason for these extra braces.
The sketchup file is my attempt at determining angles.
The pictures (Sorry they came out so big) are the final configuration after many changes in compound angles. The last is the feeder in the upside down position.

This brings me to my next question. How do you cut acute angles on either a table saw or radial arm saw? I ended up using my band saw for the cuts where the two join.

Thanks again for all the help. Now to prime and paint ( to hide).

Regards,
walnut732
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Old 07-07-2020, 11:54 AM
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Black Bears are starting to be a real problem in the Orlando, FL area due to
the loss of habitat (stupid construction is out of control). bird feeders are on the
verge of being outlawed along with leaving pet food outside after dark.
I would suggest you re-think your whole situation of a wood project and consider
something a little more robust. like an all metal pipe assembly.
3" Galvanized Rigid Steel Conduit Pipe comes to mind.
(too slick for bears to climb. a few feet in the ground with cement for ballast).

.

there is no educational alternative to having a front row seat in the School of Hard Knocks.

Last edited by John Smith_inFL; 07-07-2020 at 11:58 AM.
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Old 07-07-2020, 01:33 PM
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Indeed, it would be more reliable to weld a metal frame. But will it save much from the bear?
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Old 07-08-2020, 01:19 PM Thread Starter
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I live in PA so we have had bears for a long time. As I mentioned the original feeder was schedule 40 pipe which one bear bent as if it were macaroni. I have relocated this feeder many times and now it is in a location that I can take it down easily. Unfortunately the bear was so quite the last go round he took it down before I could remove it.

My wife has suggested I leave it down until they go into hibernation. That is what I'll do.

Regards
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Old 07-08-2020, 01:58 PM
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I just came across this calculator and suggest that you save it for this link for any future need. I have only done a few tests with it, and it seems to work great, so I am keeping the link handy.

Charley

http://www.pdxtex.com/canoe/compound.htm
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Old 07-09-2020, 11:11 AM Thread Starter
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Thanks, I put that into my Bookmarked pages.

Regards,
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