Cutting a wooden box into 2 pieces, with special shape

Question

I want to cut a wooden box (3 X 3 X 3 INCH) the same as the attached image. Every CNC shop told me that they cannot do that. I tried to do it with regular saw, but it wasn't good as you can see.

Does someone have an idea how to do it?

Thanks!

The desired result:

What I did:

Answer 1

Warning

I don't think it necessary but there are several links in this answer that are directly related to the horror movie Hellraiser. If you have issues with that type of content don't click on the links.

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So it looks like what you are trying to make is a variation of the Movable Star Lament Configuration. I cannot seem to find any plans to reference or anyone that has done it will an accurate build process for this so it looks like we have to guess a little.

Still was does seen obvious is that we should be using 2 blocks to create this instead of one. A bandsaw, chisel, gouge and drill press appear to be the tools of choice for making this.

Make a template

First thing I would do is make a template on the computer and print them out several times for each face (4 assuming you don't have any oops moments.) You should be able to draw this out with a circle in the middle and a series of intersecting lines. It looks like the block is cut up into 16 equal parts. That gives us angles of 22.5 degrees. So with that in mind:

Then you could colour or mark the template to show what needs to be removed. The kerf of the blade should allow the to fit well if both blocks are cut from the same template

Circle

I think that you should cut the circle out first. Using a Forstner bit, like Steven suggests, would ensure you get a flat surface when you stop drilling. That's a lot of waste to clear out so make sure you clean out the hole as you progress (not while it is on of course).

The "interlock"

Once the circle is out then you can cut the alternating "keys". Clean up in between the keys with a chisel and the insides of the keys with a gouge to match the curve of the circle. Worry more about the faces that people will see more then the inside. Just like you see in this photo (before it was cleaned... presumably with a chisel):

_{(source: thekingofbelgium.com)}

_{Image from The Puzzle Box Shop}

An after thought would be you could still use the template and if the outside edges don't match up perfectly then you could just trim with the bandsaw to make it square.

Finishing side note

According to the site the where you pictures come from they put an ebony veneer on the end grain of that mahogany wood. Guessing that was done to help make a more uniform stain/finishing. The second set of blocks (candle holders maybe?) also look like they have a veneered top.

Answer 2

The two boxes in your picture both appear to be composed of many individually-cut parts.

If you look at the zoomed-in pictures of the one on the left, you'll see that the direction of the grain is inconsistent on many parts. If you look closely at the one on the right, it looks as though the exposed faces, edges, and ends are all veneered.

You can produce a more seamless-looking box as follows:

1. Cut a thin slice off the top and bottom with a bandsaw or handsaw (I'll later refer to these as the top and bottom veneers)
2. Using a Forstner bit, bore a hole all the way through the middle of the block, from top to bottom (preferably with a sacrificial backing board or drilling most of the way through from the top, then flipping the block over and finishing from the bottom side to avoid blowing out the bottom)
3. Make the outward-radiating cuts with a bandsaw or handsaw
4. Cut two pieces of dowel (one for each piece of the box, preferably of the same species as the rest of the box for the most seamless appearance)
5. Glue half the "legs" onto one dowel, and the other half onto the other dowel.
6. Glue the top veneer onto the top face of the top piece and the bottom veneer onto the bottom face of the bottom piece.
7. Trim the voids out of the veneers, using the legs/rays as your guides.

Answer 3

My guess at how they built this: Start with two identically shaped squares. Core out the center half way of each one with a forstner bit. Then trace the matching patterns onto each piece and cut them out with a bandsaw.

It might also be possible to use a router to cut out the groves instead of a bandsaw.

Either way, you're going to need very accurate measurements and marks to get this right. Probably best to cut it a bit "tight" and then chisel down to fit.