|Right off the saw!|
Make a cube. Label all the corners as A or B so that each edge connects an A with a B. Now draw straight lines connecting the A corners. Saw off the B corners using those lines. You have an accurate tetrahedron without needing to make any length or angle measurements. The edge length of your tetrahedron is 1.414 times the edge length of your cube. You recognize the square root of two there.
This got me thinking that perhaps there is a good way to lay out the tetrahedron with no measuring at all. Just my cup of tea.
I asked Tim for a sketch, and while I waited I found this on YouTube:
It turns out this is exactly what he was talking about. This second way is a great way because there is no measuring, no math calculations, no angles that aren't on my combination square to worry about.
Right up my alley. I decided to try it out.
|Start with a block of wood. Duh!|
Then, mark the diagonals on each face as per Tim's instructions.
|Then it is just a matter of sawing them out like on the video!|
|Perfect cube off the saw.|
|Finishing the saw cuts.|
|A pretty darned good tetrahedron!|
With just a little care, I was able to make this tetrahedron without any trimming with a plane. It is plenty good enough for my purposes. I am excited now to try it on the real thing: ebony.
The only reason I want to use ebony is I happen to have some laying about. I think pretty much any hardwood would do for these dice. I think the heavier and tighter grained, the better. We'll soon see.
What I will do after cutting the ebony out, is polish the tetrahedrons (tetrahedri?) with fine sandpaper. That is, if I can get them as accurate off the saw as I did this pine one. I also expect it to be a bit more challenging because the ebony ones will be smaller.
In addition, I have an idea that I got from another YouTube video for making some appropriate dice from some regular rectangular stock. There's no reason this has to be so complicated, other than I think the tetrahedrons were a more high-end version for the wealthy, just like the original inlaid game board. There is evidence this game was played with knuckle bones from goats.
This can be a simple game that can be made in a hurry. Stay tuned...
Lastly, I would like to give my most humble thanks to both Sylvain and Tim for sharing their knowledge with a simpleton like me. My first instinct was to start whittling on a stick until I came up with something that more or less suited. Both of these methods are highly superior and are capable of repeatable, accurate results. Guys, have a beer on me.