BEVEL HELP for a tetrahedron - Page 2 - Woodworking Talk - Woodworkers Forum
Old 03-08-2018, 08:51 AM
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Originally Posted by AltcarBob View Post
T...All this thinking about angles and dangles and swings on the wonk has given me a headache that can only be cured by lying on the floor in a darkened room at 45 degrees to the wall...

LOL...!!!

From my shared quotes...You and Tennessee Tim are those kind'a folks that:

"...I do, and I understand..."

Which is the most important finalization, and there is nothing wrong at all being an "empirical and practical person!!!"

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Old 03-08-2018, 10:34 AM Thread Starter
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54.736 is the consensus?

Hello, and thank you all for your input! Jay your 3D rendering is exactly what I am talking about making. I appreciate the in depth explanation shown so clearly. Also great link AltCar. So I take from this that the angle the saw needs to be set at is 54.736? If so how can I actually cut that angle on a table saw? Don't most only adjust to around 45degrees? Also, my digital angle gauge only goes to the 1/10 of a degree. I am so glad I found this site with all this combined knowledge!

Last edited by PACHY; 03-08-2018 at 10:40 AM.
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Old 03-08-2018, 11:06 AM
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Originally Posted by PACHY View Post
Hello, and thank you all for your input! Jay your 3D rendering is exactly what I am talking about making. I appreciate the in depth explanation shown so clearly. Also great link AltCar. So I take from this that the angle the saw needs to be set at is 54.736? If so how can I actually cut that angle on a table saw? Don't most only adjust to around 45degrees? Also, my digital angle gauge only goes to the 1/10 of a degree. I am so glad I found this site with all this combined knowledge!
Hi Pachy,

I have built tetrahedrons almost exactly as you have described for educational aids when teaching. Some still live in some elementary and middle schools.

If the format is not to large a piece of wood, or can be created as a "frame armature," you will work with the piece of wood in a vertical format with it aligned to the table saw fence. Like I have it in my illustration. Then your blade only needs to tilt to 35.264°

If you have something like my "Wixey" digital angle gauge, just set it to the closest decimal point rounded up. I then adjust (if really necessary) with my low angle block plane, but with a new/sharp blade on the saw, seldom is this nessary.

Does that make it clearer?

Regards,

j
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Old 03-08-2018, 11:36 AM Thread Starter
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Wood sheets

Hi Jay, I need to make it out of sheets of wood as opposed to the frame armature. So you are saying to take my precut equilateral triangles, put them on end and rip the bevels that way, with the saw at 35.264 degrees? Thanks again
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Old 03-08-2018, 12:12 PM
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Originally Posted by PACHY View Post
Hi Jay, I need to make it out of sheets of wood as opposed to the frame armature. So you are saying to take my precut equilateral triangles, put them on end and rip the bevels that way, with the saw at 35.264 degrees? Thanks again
Yep..."By George...I think he has it!!"

If you give me the exact dimensions of you materials, there makeup (aka what they are), and over design plan; I should be able to provide you a picture here on your post thread of what you want to do to scale without much effort or bother...If that would help? Otherwise, I am about 98% sure you have a good mental picture already...

Good Luck, and look forward to some final project pictures...

j

Last edited by 35015; 03-08-2018 at 12:25 PM.
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Old 03-08-2018, 12:18 PM
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Double post

Measure twice, Cut once, Then force it to fit with a big hammer.
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Old 03-08-2018, 12:19 PM
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Originally Posted by PACHY View Post
Hi Jay, I need to make it out of sheets of wood as opposed to the frame armature. So you are saying to take my precut equilateral triangles, put them on end and rip the bevels that way, with the saw at 35.264 degrees? Thanks again
I wouldnt worry about going to 3 decimal points with timber or particle board, .2 or .3 degrees should be fine. A bit of damp in the air or central heating will change your measurments more than .264 of a degree.

I highly reccomend doing as I did and making a test piece out of foam core board first. Its really easy to cut with a sharp knife, its cheap (I got 5 x A3 sheets for £6), its sandable and you can check all your angles with a Bevel guage before you get to the table saw.

Measure twice, Cut once, Then force it to fit with a big hammer.
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Old 03-08-2018, 12:29 PM
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Originally Posted by AltcarBob View Post
I wouldnt worry about going to 3 decimal points with timber or particle board, .2 or .3 degrees should be fine. A bit of damp in the air or central heating will change your measurments more than .264 of a degree.

I highly reccomend doing as I did and making a test piece out of foam core board first. Its really easy to cut with a sharp knife, its cheap (I got 5 x A3 sheets for £6), its sandable and you can check all your angles with a Bevel guage before you get to the table saw.
I agree...modeling always helps with a final design facilitation...

In this case it was (or like many things today) can be done in CAD...or in hand drawn form. The "math" is the back-check, and in this case is done already. As such, I was able to go directly to stock (white pine scrap) and cut one of the exact facets of the tetrahedron as in the CAD model image I shared below, without any "testing" to see if it would work...

The math was the "back check"...the CAD was the "testing" and the first attempt in material provided proof of concept...

I personally use whatever decimal point furthest I can get to with a tool setting...be it 1 or 3 decimal points. Just like I design to 0.5mm even on huge timber frames and layout the same way...As the old adage goes from days as a Marine..."...aim small...miss small..." It works and applies well in craft to...

Last edited by 35015; 03-08-2018 at 12:34 PM.
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Old 03-08-2018, 03:01 PM
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Originally Posted by Jay C. White Cloud View Post
I agree...modeling always helps with a final design facilitation...
It certainly helps with me I have a habit of reversing things when designing or marking out, I cant help it no matter how many times I measure something between my brain and my pencil gets back to front. Manys the time I have made two backs or two lefts but if I have a small 1/4 scale model made out of card, foam board or scraps to look at it almost always stops me from adding to the firewood pile. I dont know if its being able to look at a 3D model or the building of the model that helps.

Measure twice, Cut once, Then force it to fit with a big hammer.
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Old 03-08-2018, 03:18 PM
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It certainly helps with me I have a habit of reversing things when designing or marking out, I cant help it no matter how many times I measure something between my brain and my pencil gets back to front. Manys the time I have made two backs or two lefts but if I have a small 1/4 scale model made out of card, foam board or scraps to look at it almost always stops me from adding to the firewood pile. I dont know if its being able to look at a 3D model or the building of the model that helps.
Whatever is time efficient, economical and works for you should be employed...Be that a scale "touch model" and/or CAD modeling.

For me, I keep a CAD open when working, as a piece is laid out, it is checked against the cad, when complete...that component is erased from the CAD and I move on. This creates a running inventory and is instantly clear what is left to achieve before completion. In the past, I relied exclusively on good isometric plans in the same fashion.
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Old 03-09-2018, 12:00 PM Thread Starter
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Looking forward to making this!

Thanks again to everyone for your help, Jay especially. I'm pretty sure you are probably the coolest person ever, far wiser and more experienced than I. And that is exactly what I was hoping to find by joining the forum. If I am ever on the opposite corner of the country I will come to thank you in person! Initially I am going to make this out of 1/2-3/4" melamine board, not a respectable wood but with clay we use it for its ability to repel water a bit, at least where it is coated. Most likely I will start with 12" sides on the equilateral triangles. I have family that has a table saw so hopefully if I have time this weekend I will try and get this made. This is the first of about 10+ steps in my process, so the final final piece is a ways away. I will however post pictures once I get the initial form made. I am sure I will have more questions in the future!

Last edited by PACHY; 03-09-2018 at 12:03 PM.
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Old 03-09-2018, 12:18 PM
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Thanks again to everyone for your help, Jay especially. I'm pretty sure you are probably the coolest person ever, far wiser and more experienced than I. And that is exactly what I was hoping to find by joining the forum. If I am ever on the opposite corner of the country I will come to thank you in person! Initially I am going to make this out of 1/2-3/4" melamine board, not a respectable wood but with clay we use it for its ability to repel water a bit, at least where it is coated. Most likely I will start with 12" sides on the equilateral triangles. I have family that has a table saw so hopefully if I have time this weekend I will try and get this made. This is the first of about 10+ steps in my process, so the final final piece is a ways away. I will however post pictures once I get the initial form made. I am sure I will have more questions in the future!

I doubt very much I am all that...but thank you deeply. I was glad to be of help to a fellow "maker of things!"

Blessings,

j

P.S.

I travel a lot...send me an email (its here on the forum) and I will set up a contact file for you...

Er...Ah...I missed something...!!!...Did I read clay...!!!

As in like maybe stoneware perhaps just maybe please...

I also work in traditional ceramics and would love to know more about your final design...do send me an email can't wait to see progress reports here on you post thread...

Last edited by 35015; 03-09-2018 at 12:21 PM.
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