1. Web site : www.bellwoodwork.com
Puzzle Making for Woodworkers
Donald Bell
SFW Meeting, January 2011
Web site :

2. Puzzle Making for Woodworkers
What makes a good puzzle?
It should be easy to describe
Fairly easy to make (either one or many)
Not trivial to solve, but not dauntingly difficult either (solving time between 10 and 30 minutes, perhaps)
The “look and feel” should be attractive
There should be a surprise – either an “Aha!” factor or several puzzles in one

3. Puzzle Making for Woodworkers
The puzzle-maker’s progress
Solving other people’s puzzles
Copying other people’s puzzles
Modifying other people’s puzzles
Creating original puzzles of your own
Developing the manufacturing processes
Documentation, packaging, sharing …

4. Different kinds of puzzle illustrated here
put-together puzzles (2D) - put-together puzzles (3D) - "steady hand" puzzles - sequential puzzles
Also (but not shown here)
take-apart puzzles - (especially "burr" puzzles) - scroll-saw puzzles - sliding block puzzles - secret compartment boxes

5. More kinds of puzzle illustrated here (back cover of same book)
put-together puzzles - "steady hand" puzzles - sequential puzzles
Also (not really puzzles)
magic tricks - games of skill

6. The “Blockhead” Puzzle
- Easy to describe
Not hard to make
Not trivial to solve
- Definitely an “Aha!” moment when you work out how to do it

7. A Brief Tour of the Workshop
Band Saw Record Power BS 350 1½ HP
cut depth 230mm, throat 340mm

8. Woodturning Lathe
Record Power, Model CL3
¾ HP, 5-speed belt drive

9. Table Saw
Record Power TS200SB
2 HP, 4000 rpm
250mm (10") blade
Sliding Beam
(605mm travel)

10. Sliding Beam, Mitre Fence, 45 degree tilt

11. Disk Sander Clarke CDS 300
300mm diameter 1 HP, 1450 rpm

12. Radial Arm Drill Press Axminster AWBRD550 ¾ HP, 5 speed belt drive

13. Portable Router
Clarke Contractor CR2
3 HP, rpm ½" collet

14. The Puzzle Maker's Toolkit

15. A few puzzles for you to play with – this is a secret opening box (there is something under that thumb!)

16. A well-known, easy to make puzzle The "Soma" Cube
Four small cubes can be put together in eight different ways, including a straight stick and a square. The other six pieces, plus a 3-cube L-shape, make up the Soma Cube Puzzle.
Easy to make and not too hard to solve. There are 240 solutions
Alternatively, take away the L-shape piece and use the other six pieces to make a big L-shape twice the size. A bit harder.

17. A puzzle with an "Aha!" factor
Conways's Curious Cube
Six of the pieces are 2" x 2" x 1" blocks.
And there are three 1" x 1" x 1" cubes.
They can be assembled into a 3" x 3" x 3" cube, but there is only one way of doing it.
(John Horton Conway is a mathematician who has produced many wonderful puzzles)

18. The Fifth Chair Puzzle
The four chairs are the same shape, but different sizes.
Two small, one medium, one large.
Use them all to make a fifth (giant) chair, the same shape as the others.
Can you ALSO discover the mathematical principle that makes the puzzle possible?
Here are the dimensions of the chairs in mm.
Height
Width
Depth
Small
63.0
50.0
39.7
Medium
79.4
Large
100.0
Giant
126.0

19. Easy to Make, Very Hard to Solve
Professor Hoffman's Cube
27 identical blocks of wood (often made in 27 different types of wood)
If they were all perfect cubes, 5x5x5, they could easily be packed into a 15x15x15 cube.
But these are 4x5x6, so each one can have one of six orientations.
A 4x5x6 block has 4% less volume than a 5x5x5 cube, so there are a few small gaps in each layer
Here are the three layers of one solution, but it is hard to find