Get into the art of making wooden puzzles with this simple double cross.
There are instructions here, and a couple of videos on my YouTube channel.
Step 1: Three Bits
Cut three identical wooden pieces
Approximately three times as wide as they are thick, and three times as long as they are wide
Step 2: Mark Centres
Mark in centre lines on all the pieces, which will allow them to be aligned as the waste is defined
Centre lines divide each face of a piece into four, with lines equally spaced between opposite edges
Step 3: Piece One
Align the end of piece two with the centre of piece one's face (photo 1), and mark around it. This defines the waste to be removed from piece one, and once removed will allow the other pieces to be snugly pushed through.
Step 4: Piece Two
The same waste as piece one is marked onto piece two (see previous step)
Additionally, a central 'entry' cut is marked from one edge (see lower piece in photo). The width of the cut should equal the thickness of the pieces, and should be marked in on centre of piece two's length. Once cut out, another piece can be snugly pushed into this 'entry'.
Step 5: Piece Three
Piece three needs an entry cut equal to the thickness of the hole side wall left in the previous two pieces (the first photo shows this being measured, and the second shows it being gauged in. This entry cut is made from the centre line, towards one end.
It also requires half of the same hole made in piece one; from the centre line to the same end the entry cut is made (see the third photo)
Step 6: Summary of Pieces Ready to Cut
You should now have three pieces, with waste areas marked out as shown here.
Step 7: Remove the Waste
Saw, chop, drill, or file, the waste areas, square through the three pieces, checking for snug but sliding fit as you go--if too much material is removed, the cross will go together but look a little sloppy, so do take care
Step 8: Remove Sharp Edges
To make the puzzle nicer to handle, chamfer all external edges of all pieces. A block plane, file, or sanding block would work well.
Step 9: Assemble Your Puzzle
Of course the object of a puzzle is to work it out for yourself!
But, if you're in a hurry, or getting frustrated, then these photos should show you how it goes together.