Compound Tetrahedra

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Project by Joshuah posted 08-25-2012 09:09 PM 3217 views 23 times favorited 16 comments Add to Favorites Watch

I had made a paper one of these in a art class I took in college. I had saw it last week and decided to make one out out of wood. It is a fun, though briefly frustrating project.

By the way the wood is walnut.

Thanks for looking.

-- -Joshuah

16 comments so far

View Kookaburra's profile


748 posts in 1646 days

#1 posted 08-25-2012 09:14 PM

How ever did you figure out the cuts on this? I am very impressed. It is a lot of fun and quite attractive. I would not mind having one of these for the top of my Christmas tree.

-- Kay - Just a girl who loves wood.

View Murdock's profile


118 posts in 1906 days

#2 posted 08-25-2012 09:43 PM

That is amazing, thank you for sharing, and I am glad you took the shadow picture, that is really nice.

-- "Anyone who has never made a mistake has never tried anything new." - Albert Einstein

View Joshuah's profile


152 posts in 2115 days

#3 posted 08-25-2012 10:35 PM

Thanks Kay. Its just a little math from those geometry/trig days! I used the law of cosines…I know its has probably been a while!
It involves taking a slice of a single tetrahedral, and giving a length to each side (say 1, which in a 30-60-90 makes the other side the square root of 3 over 2.

Yada Yada Yada…Long story short… the angle between the faces is 70.5 degrees. So if you cut the rods with a (70.5)(54.75)(54.75) and you miter with 60 degree angles.

All the rods should look like this before glue up.

-- -Joshuah

View Joshuah's profile


152 posts in 2115 days

#4 posted 08-25-2012 10:38 PM

Murdock- Thank you, I found that it was hard to see the design by just looking at the wood.

-- -Joshuah

View Sasquatcher's profile


11 posts in 1547 days

#5 posted 08-25-2012 11:37 PM

I like it alot!!! And wow the law of cosines seems like ages ago!!!! Good Job!

-- Sasquatcher

View NewWoodie's profile


2 posts in 1546 days

#6 posted 08-25-2012 11:42 PM

I agree with Murdock… and sasquatcher!!!

So how did you do the finishing on a project like this! Seems very very tedious!!

-- NewWoodie

View Joshuah's profile


152 posts in 2115 days

#7 posted 08-25-2012 11:52 PM

Thanks all!! I actually did all of the sanding and most of the finishing before assembling. After assembly I think I put 3 more coats knocking it back with 300 grit in between.

-- -Joshuah

View Yuri's profile


55 posts in 2837 days

#8 posted 08-26-2012 01:42 AM

Well done.

-- Live to Learn

View Dark_Lightning's profile


2620 posts in 2531 days

#9 posted 08-26-2012 02:15 AM

Very nice! A skeletal version of a stellated icosahedron!

Ref: #17

I take it you built the tetrahedrons, intertwining the pieces as you went?

-- Random Orbital Nailer

View Joshuah's profile


152 posts in 2115 days

#10 posted 08-26-2012 03:48 AM

Very intuitive AtomJack. I hadn’t seen that link before, maybe I’ll have to step up my game and make a real complex one.
And you were spot on, I built the original tetrahedral, then would build one-by-one, locking them together as I went.

-- -Joshuah

View redryder's profile


2394 posts in 2524 days

#11 posted 08-26-2012 06:20 AM

Great project.

Man I hate math…........

-- mike...............

View deon's profile


2507 posts in 2447 days

#12 posted 08-26-2012 09:46 AM

Looks great!

-- Dreaming patterns

View FloridaArt's profile


807 posts in 2720 days

#13 posted 08-26-2012 11:10 AM

One of the most intriguing wood projects I’ve seen. Fascinating.

-- Art | Bradenton, Florida

View jusfine's profile


2405 posts in 2348 days

#14 posted 08-26-2012 03:14 PM

That looks like the way my picture frames turn out that aren’t supposed to look like that…

-- Randy "You are judged as much by the questions you ask as the answers you give..."

View Jim Jakosh's profile (online now)

Jim Jakosh

16809 posts in 2527 days

#15 posted 08-26-2012 04:36 PM

That is really cool!

AtomJack, I like to use math to get me where I want to go but those shapes blow me away!! As do the formulas!!.............Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

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