How to do this secret box on a CNC?

Yesterday I 3D printed this secret box to insert a gift for my granddaughter birthday. I was wandering how I could do it on my CNC with hardwood. I think the only way is to have some special cutter. Any suggestion?

Here are the sty file link on thingiverse:



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You could do this with a dovetail bit easily enough. Just need to plan your paths so all your plunges and retracts are outside your piece.
The angles won’t be as steep, but other than that would work the same way.

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Hi Micheal, I though of that too, but I think with this kind of angle, the aspect of the box won’t be has nice. I still may try it, will have to redesign and may 3d print it for a test, thanks.

Unfortunately, Carbide Create won’t correctly preview a dovetail tool, see:

The secret of the impossible dovetail is they are at an angle. So make multiple tool paths. Cut the widest part of the female dovetail with a flat end mill to remove the majority of the waste. Then make the dovetail cut at full depth with a longer tool path than the actual size of the dovetail. You want to plunge in outside of the cut and retract outside of the cut. I think the project is doable but will take some planning and consideration. You might want to use the painters tape and superglue workholding so clamps are not in the way. I have an L bracket I use to set up the material so it is square with the cutter, put the tape and super glue down and then remove the L bracket.

Do the same thing for the male part of the dovetail, remove the majority of the material with a flat end mill and make a full depth cut with the dovetail bit.

You cannot make incremental cuts with the dovetail like a pocket but you can move the dovetail bit over at full depth and then make incremental cuts at full depth till your dovetail is completely formed.

You can always make one by hand :slight_smile:


Will, for this kind of project I would use Fusion360.

Guy, I would use a similar process too but dovetail router bit have a quite different angle, 7 to 14 degrees angle, much different than this model. With google, I found some similar wooden boxes all with the same angle and they are at low prices. They must use some jigs on the table saws?

Nick, thanks for this video, interesting! Wandering if the change in humidity thru seasons will affect the operation. Would not think doing those kind of work by hands, not enough skills and patience! :slight_smile:

Simple enough to do in OpenSCAD:

It’d be pretty straight-forward to take the model and cut it w/ a dovetail tool which matches what is entered into the parameters.

Thanks Will, I am not familiar at all with BlocksCAD neither OpenSCAD, but I will look at it and I have a good friend who is familiar with OpenSCAD, he will help me.

Really wish it was straight-forward getting DXFs suitable for cutting out of OpenSCAD — for one approach see:

Drawing up the design in Carbide Create is pretty workable:

Draw a square for the outline of the box:

Rotate 45 degreees:

Draw up the dovetail tool in profile:

and draw in a rectangle to measure the width of the dovetail slot:

Draw in a square to get the size:

scale by 0.5 to get half:

and reposition:

Select the rectangle for the pocket and align it:

Then increase the size as necessary to cut away completely:

and draw in a straight line along the center:

copy-paste the line and the rectangle into place so as to duplicate them:

Then select the rotated rectangle and flip horizontally:

Draw in the dovetail tool to verify that it will clear:

and if it doesn’t, increase lengths so that it does:

Rotate everything back:

and assign toolpaths:

As noted, you won’t get a correct preview:

You’ll also want to draw in a pocket so that it will serve as a box rather than a puzzle, and add either a ball-catch or magnet.

An elongated pocket increases the storage volume:

Duplicate the file and adjust as necessary to cut the negative of the dovetails so as to make the lid.

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