When challenged to make a twenty sided widget (icosahedron) from solid wood, I looked about on these here intertubes for some assistance to no avail. Lot’s of guides on making the polygon out of paper and even a few about shaving and gluing a bunch of equilateral triangles together for a hollow creation. I had to figure it out on my own, so I thought I’d share.
For anyone that would be interested in purchasing some handmade ones from my etsy store, please feel free to contact me there or in the comments below!
Start with a Cube:
start with a cube
While looking at a borrowed D20, I noticed that there appeared to be triangle pairs that were the same on six opposing sides of the die. So i figured out how to make one starting with a cube. The blue lines above show the orientation of the shared edges for these triangle pairs.
42 really is the answer:
cut at 21 degrees
Another thing the D20 I borrowed taught me was the angle difference between these paired sides was 42 degrees. If we set the blade on whatever saw we’re using (bandsaw, tablesaw, mitersaw, etc.) to 21 degrees and then cutting one of the faces of the cube right to the middle, it will get us all the right angles.
Cut Two Opposing Sides:
two sides cut
Using this 21 degree cut, we will cut off the top and the bottom of two opposing sides, which will result in the shape above. Now to reorient the cube, to cut the next pair of opposing sides.
It’s important to ensure the new 42 degree edge you’re creating does not connect across adjacent cube sides. Refer back to the “start with a cube” picture if needed, they all need to be oriented differently. Should you mistakenly cut two adjacent sides at the same orientation, congratulations, you get to start over.
Cut Four Sides:
four sides cut
Once we’ve flipped the cube over to address the next pair of opposing sides, use the same process to cut the top and bottom of each.
Cut Six Sides:
cutting six sides
One more reorientation of the original cube and we can dispense of the last remaining original sides. Should look something like the shape above.
(EXTRA: If you had accidentally set your blade angle to 30 degrees, all these sides should be pretty close to perfect pentagons, and you got yourself a nice dodecahedron.)
Cutting Corners: (See what I did there?)
cutting corners
You may be tempted to set your saw back from that obnoxious 21 degree setting, but wait. You need to keep it there all the way through. The last step to finishing up this d20 is to deal with what used to be the corners of the original cube. I found it best to draw out the cuts on the surface so I wouldn’t get lost half-way through this step. Essentially, you’ll be cutting a equilateral triangle where three of the pentagons meet, NEVER on the long edge you created in the middle of the six sides on the cube. Confused? I don’t know how else to say it, but if you turn the thing around in your hands and scribble it out first, I think it will make sense.
Finished:
twenty sided die
Well, there you go. Wasn’t that easy?
This was also a good excuse to learn how to use blender.
vonholdt 
You sir deserve an award
thanks, it was fun figuring this out
Wow! I don’t have a whole lot else to add, I’m still stunned at your approach. Very well done!
thanks!
so whats the chance of doin the same with a stone but no saw? maybe sandpaper or a sander of some sorts
i imagine that would be possible, but i don’t have the tools for something like that. i have made a cubish widget out of concrete by making a wooden mold. maybe with a 3D printed mold for a d20?
i used a mitre saw to make one. first 2 series of cuts no problem, 3rd had to make a cradle to hold the die. the fourth cut could not do it. so i just used the sanding belt. came out ok.
that’s awesome! definitely got more dicey (pun intended) to keep it steady with each cut. i too used the parts i just cut off to cradle it.
you should make a video
Thanks a lot for this. I looked up how to make one few years ago and didn’t find anything. Now I am going to try one (hand carved but the same idea).
no problem, it was a fun problem to solve
Done! Check my blog – http://alesthewoodcarver.blogspot.ca/2016/10/hand-carved-20-sided-die-in-basswood.html
Once again thank You for the manual.
awesome work!
I tried to figure it out myself how to create a D20 out of solid wood, so I tried to visualize the process in SketchUp. I got to the part where you get the uneven pentagons and I thought “Duh, that’s bad. It’s becoming a boring (and warped) D12. What’s the matter?”
And then I found your website and realized that I was actually still on the right way! Thank you, man! You made my day! 🙂
that’s awesome, glad i could help!
What size block of wood did you use? 4×4, 6×6??
4×4″
Thanks for the quick answer. Also Thank you for sharing this awesome idea!
I don’t suppose there is any chance I could bribe you to help me make four of the 4 x 4 sized d20’s? I had a woodworking friend with a bandsaw try to no avail and I can’t seem to do it on my chopsaw with a 21 degree angle…:(
Liz
i could probably do that. can you make a custom request on my etsy store and we can chat there?
Sure and Thank you for considering it.
I am searching for a large 20 sided die for my son’s and daughter-in-laws’s wedding sign-in. Depending on the size, I would probably need more than one. I wanted to surprise them, since they have been searching for this item, with no luck. How much would you charge to make these?
I’m going to start to make a set of dice out of stone soon… I’m going to try to use your tutorial to achieve my goal… I don’t quite understand everything even with the blender visuals.. can you make a video…
i don’t know about the very near future, but perhaps i could try this sometime. i found it was easiest to figure out how to make the shape out of a scrap piece of wood first. it allowed for cheap mistakes.
how would i scale this down to work on the bandsaw with about a 1 inch cube
carefully. not really sure that size changes the setup. you could cut a few large sleds and support angles at 21° then figure out how to clamp your material into them for each cut. i’ll post a picture of the sled i ise most of the time.
at that size your could almost do the wjole thing with a belt or disc sander.
how big was the finished product?
starting with a roughly 3.5″ cube results in about a softball sized die.
Hello! Just a quick question (and I don’t know if you would even know this) but: Do you think this would work with antler, instead of wood? Also, do you have any tips for adding numbers to each face?
i’ve never worked with antler but i assume it would work the same if you set up a tiny miter box. I generally stain or paint the numbers on, but i’ve seen others that carve or burn them in. i would say to try out different methods on some of the flat-sided waist material you made cutting out the shape. then you can find what works best for you. best of luck, i’d love to see how it comes out!
Thanks for posting this. If I get any free time, I want to try making these in the future.
cool, good luck!
Is there any particular length or ratio that you cut into the cube with that 21 degree angle, or do you have to just get a feel for it?
i usually draw a line straight done the center of the sides (the first image “start with a cube”) and then cut right up to that line. the exact length will vary with the dimensions of the original cube. good luck, some day i plan to build a little sled to hold the cube so i can leave my blade at 90°
I had a half-dozen failed attempts at this before I recreated the Blender setup and figured out where I was going wrong. The 21-degree cuts to make a dodecahedron are right, but you need a 36-degree cut to convert the dodecahedron into an icosahedron. I don’t know how you can do it with a 21-degree cut unless you’re tilting the workpiece to compensate.
In case it helps anyone else out, my basic approach was:
1. Make a cube.
2. Make 2 21-degree cuts on each of 4 faces of the cube.
3. Use bits of carpet tape to attach some of the cutoffs from (2) back onto 2 opposing faces of the cube (so they’re flat enough to safely run the piece through the bandsaw).
4. Make the remaining 21-degree cuts (at this point you have a dodecahedron).
5. Mark the cuts to remove the corners of the dodecahedron.
6. Cut off the corners using 36-degree cuts.
7) Remove the taped-on bits.
Net result: https://i.imgur.com/MLswohf.jpg
Looks nice! I’m glad you were able to figure out your way around it.
Nice!
Heya,
I know this is 4 years old but I just read this and it was very helpful. Can you reach out to me and let me know how you actually did the cutting? Did you make a jig for a table saw? I’m interested in the logistics of how you actually cut it. Thanks!
i sort of clamped some cut off pieces together to make a sled but nothing of real quality. i always imagined making or 3d printing a series of sleds to do these the right way in the future, but have yet to take the time to do that.
Brilliant!
Thank you, I can’t wait to attempt this!
I’m trying to make the D20 as shown. However, I’m having trouble understanding the instructions.
I start with a 3″ cube, set my miter saw to 21 degrees and make the first cut. What I don’t understand is:
“cutting one of the faces of the cube right to the middle”
The figure you show looks like the cut is all the way from one face to the other face of the cube. “3 1/4″ cut for a 3″ cube.”
What am I not understanding?
I suppose if you visualize the cube and the first side you want to cut is the roof. Draw a line right down the middle where the ridge of the roof would be and then, with the miter set at 21°, you cut the roof slope off each side just up to the ridge. I’m not sure if that helps?
got it… thanks
Well done Good sir. The easiest of all the complicated ways of getting dice ready for d& d. Thanks for the 30 degree tip for the dodecahedron. Another great tip for die making nr two. How about tips for all Platonic solids?? Respect
By the way: the mitre saw is really dangerous. Using a disc sander was easy and a lot safer.
indeed, if one has a disc sander
thanks, i haven’t yet had a reason to try and figure out the other solids yet.
this is a pretty good video for making them all from solid wood blocks.
Hello! my last comment didn’t go through, so I hope this one makes it. I used your method to make a whole lot of dice for my dice addicted brother and posted the results on facebook. A few people online and in-person have asked for me to do a walkthrough video of how I built my sled and my tips on the process. Before I post anything though, I wanted to get your blessing. I would make sure you are credited appropriately. Let me know if this is ok, I just don’t want to pass off your amazing work as my own
sorry, i realize you asked almost a year ago but i have been off wordpress for some time. i absolutely approve and hope that you went ahead and shared you process a long time ago! thank you for thinking to ask, sorry i didn’t see this sooner.
We successfully made several using your method. However, we found it very difficult to get an exact mathmatically correct Icosahedron and had to hand adjust the facets. We are making them out of solid copper. I have recently switched to making them with a CNC mill.
Rodger Olds
Hi Vonholdt,
I’ve tried your process of making the solid D20 and found it really helpful! I can knock them out fairly quick now just using the cut offs to shim under the piece when needed but still have to draw the last lines on and site the cut without a jig to complete it.
Have you attempted a D10 yet? I’m interested how you would go about it.
I have not tried a D10, but now you’ve made me curious! I’m glad to hear my questionable process has helped you out!