Another Aha puzzle Blockhead Bill Cutler won the

Another "Aha!" puzzle “Blockhead” Bill Cutler won the Grand Prize at the 1986 Hikimi Wooden Puzzle Competition. Four blocks in a box - Tip them out and then try to put them back! - It’s harder than it looks This one can be made on the table saw without the use of jigs

The “Blockhead” Puzzle - The four blocks are not quite cubical - Square on the top - One side vertical - Two sides sloping OUT at 5 degrees - One side sloping IN at 10 degrees

The “Blockhead” Puzzle The sides of the box are undercut by 5 degrees The box opening is 81 mm square (to accommodate the 40 mm blocks)

The “Blockhead” Puzzle The sides of the box are undercut by 5 degrees, then mitred at 45 degrees for the corners. A 6 mm plywood base to finish

The “Blockhead” Puzzle The stock for the blocks is 40 mm thick, then cut at 5 degree and 10 degree angles, giving a width of 40 mm on the top Some trial cuts may be needed to get the 40 mm width just right

“Blockhead” Puzzle The "stick" is clamped to the sliding beam, the mitre gauge is set to 0 degrees for the first cut (maybe trimming the wood after the previous block) The stick is advanced to meet the guide block (fixed to the rip-fence with double sided tape) The mitre gauge is set to 5 degrees for the second cut Then the process is repeated. Note that there is a danger of getting both "right handed" and "left handed" blocks (the puzzle would then be impossible!)

A puzzle that needs a complex jig Nob's "never-ending" puzzle (Nob Yoshigahara – famous puzzle maker) A cube, sliced in half by an oblique plane

Nob's never-ending puzzle The two half-cubes can be glued together in an L-shape, 16 different ways

Nob's never-ending puzzle Eight of the possible 16 pieces form "Nob's Never-Ending Puzzle"

Nob's never-ending puzzle They can be assembled into many interesting shapes (with some difficulty)

Nob's never-ending puzzle Actually only 11 shapes can be made (and some need to be supported)

Nob's puzzle – making the pieces Making a small cube (just 40 mm on a side) and then slicing it across would be difficult, inaccurate and even dangerous Better to cut a small piece away from a big piece

TS 200 C Table Saw with "Sliding Beam" The part of the table to the left of the saw blade can slide to and fro 600 mm on rollers. Jigs can be fixed to the T-section slot

Nob's puzzle – making the pieces Jig mounted on the sliding beam has a bar at 90 degrees and a V-groove at 82 degrees The bolt head engages with the T-slot

Nob's puzzle – making the pieces Square section stock, 40 mm x 40 mm, ripped on the table saw

Nob's puzzle – making the pieces The saw cuts part way through the jig. The stock is held in the Vgroove, offset by 8 degrees. Note the end stop - a plastic "corner join" block and a bolt

Nob's puzzle – making the pieces When the cut is finished, the small half cube must not be free to move – it might jam between the rotating blade and the end-stop A plywood hold-down plate is used, secured with three screws. This anchors the half-cube at the end of the cut. There is not much contact area – the plate is the most secure method

The sequence of making the pieces First trim a number of pieces straight across, using the 90 degree guide Then, using the Vgroove: - slide a long piece up to the end-stop - secure it with the plate and screws - cut through, thereby making a half-cube - set aside the long piece for later trimming