Make a 3D Wooden Jigsaw Puzzle - Canadian Woodworking Magazine

Gift Project: Whether working alone or with friends and family, assembling a jigsaw puzzle can be fun, and completing one can be very gratifying. The same can be said about making one, and watching someone enjoy putting it together (or at least trying to) is especially enjoyable.

3D Wooden Jigsaw Puzzle

Make a 3D Wooden Jigsaw Puzzle



Photos by Chris Wong

INFO:DIFFICULTY – 3/5, LENGTH/TIME – 3/5, COST – 1/5

A wooden jigsaw puzzle doesn’t require much in the way of tooling, and can often be made from scrap wood. Small ones can be completed in less than half an hour, while still providing a good challenge for anyone of any age.
 
A scroll saw is the ideal tool for cutting jigsaw puzzles. Manual fret saws and coping saws are also viable options and perhaps offer slightly more control, but at the cost of speed, and some skill is required to keep these saws at a consistent angle. A band saw, equipped with a fine blade, would also work for larger jigsaw pieces.
 

Why make 2D puzzles when you can make 3D puzzles?

I made many 2D tray puzzles from Baltic birch before developing a more intricate and complex style of puzzle. Made of solid hard woods up to about 1" thick, 3D puzzles are different from their 2D cousins in that a 3D puzzle is also segmented in multiple interlocking layers. My most complex puzzles involve segments that must be assembled in a particular order, and then those segments must be assembled in order due to tapered one-way joints.
 
If you can cut 2D jigsaw puzzle pieces, you can cut 3D jigsaw puzzle pieces – the differences are in the positioning of the material as it is being cut and in the sequence of cuts.
 

Material selection

If you’re an experienced scroller, you already know which materials are suitable. What you’re looking for is a material strong enough to hold together after significant details are cut into it. Softer woods like pine and fir work, but the pieces have to be a little chunkier to survive.
 
My preferred material is a tight-grained wood of medium density that isn’t stringy and splintery, which often results in any delicate, short-grained areas failing. I’d recommend woods like cherry or maple. These materials are nice to work with and are strong enough to hold fine detail. Denser woods are okay as well, but are harder to cut - cutting small pieces of medium-density 1"-thick material on a scroll saw is enough of a task on its own. I would suggest avoiding wood with splits or other structural defects unless you can incorporate them into the design.
 

Blade selection

Since we’re cutting relatively thick material, I opt for the coarsest blades I can find. A reverse tooth pattern has most of the teeth pointing down with the bottom few teeth pointing up, to ensure a clean cut without splintering on either face. I have been using Olsen Reverse Double Skip Tooth blades with 14 TPI.
 
Coarser blades are suitable for cutting thicker stock. They are thicker and wider than fine-toothed blades, which means that they leave a wider kerf and can’t corner quite as well. This means that your puzzle pieces won’t fit together quite as tightly, and knobs need to be more pronounced to interlock. These are not problems, but you need to be aware of the trade-offs when choosing a blade.
 
Blade Types – From top to bottom: crown tooth, standard blade, skip tooth reversing and fine reversing blade. Wong finds the bottom two most useful for jigsaw puzzles.
 

Stock preparation

The material you use doesn’t need to be perfectly flat, since there will be some play between the pieces from the saw kerf.
 
Sanding a bunch of loose puzzle pieces isn’t much fun, so it’s best to sand the wood up to 180-grit first. Don’t forget the edges. While manipulating stock on my scroll saw table, it often gets a little marked up, but at least with the pre-sanding, I minimize the amount of sanding that needs to be done afterwards. Applying masking tape to the bottom surface can avoid the second sanding step, but then you have to remove the tape from every piece afterwards, and I find this to be the more difficult route.
 
If you want to ensure every piece is the same size, take the time to draw a grid on the top side. The grid should consist of squares about 3/4"-1". Any smaller, and the pieces are hard to hold, and any larger makes stage-two cutting challenging on a scroll saw.
 
Again, if you don’t want to have to sand the marks off afterwards, you can first apply masking tape. You may wish to either draw each knob/socket, indicate which way the knob faces, or simply decide as you cut them. I prefer this latter method and I’ve never had a problem forgetting to cut a knob.
 

Set-up and warm-up to make a wooden jigsaw puzzle

The scroll saw table should be at a comfortable height. Some scrollers prefer the saw to be tilted towards them, while others prefer it level. One handy feature is a foot switch to allow you to start and stop the saw while keeping both hands on the workpiece. I feel that this is more of a necessity for pierced work, where the blade often starts in contact with the work, but it is still a valuable accessory and helpful in case the blade binds.
 
Install the blade in the scroll saw and apply tension. I go by sound, listening for a sharp ping when plucked. Check that the blade is square to the table as viewed from the front and side. An easy way to check the squareness as viewed from the front is to make a stopped cut in a thick piece of material and, with the saw turned off, rotate it 180° around the blade and see if it will slide over the back of the blade from the rear.
 
Before starting work on the actual work piece, I like to warm up and spend a few minutes making some back-and-forth cuts in material from the scrap bin. This will give you a chance to get used to how the blade and saw cuts, and gauge how tight the corners are you can make. Cut some knobs too, for practice.
 
Check for Straight – It’s easiest to create puzzles when the blade is running perpendicular to the table. To check, make a small cut in some wood, then rotate the piece of wood around to the back of the blade, keeping the same face downward. The difference will be doubled and therefore easier to see.
 
Practice First – Using some waste is the best way to get to know what your scroll saw is capable of, and how different blades cut.
 

About jigsaw puzzles

To understand how to cut a 3D puzzle, it helps to be familiar with how to cut a regular jigsaw puzzle. The success is largely dependent on your dexterity and control with the saw. Despite my experience with a scroll saw, I still find that the saw is capable of cutting curves tighter than I think it should. Therefore, when making cuts on the scroll saw, I move the wood how I want to cut it, not necessarily what I think the saw can handle. And I have made more than a few cuts that surprised me.
 
Smooth, flowing movements are key to nicely rounded shapes. Start-and-stop movements will usually result in faceted surfaces that don’t look as nice.
 
The knobs and sockets are what hold puzzle pieces together. They are cut at the same time, with only the kerf of the blade between them. This means that you don’t have any room for relief cuts, and your only way is forward.
 
A good jigsaw puzzle knob is pronounced enough from its neck to be trapped in the socket. This exact amount will depend on the kerf of the saw blade being used. The neck also needs to be substantial enough to withstand handling.
 
The knob also cannot be so large that the socket of the mating piece is weak. When determining the size of the knobs and sockets, keep in mind that the puzzle piece will require 1-3 more knobs/ sockets on its other edges. Despite the apparent fragility of a completed 3D puzzle, I feel that they are quite rugged, and I can throw and spin them in the air without them coming apart.
 

A few pointers

Have a clean space to put puzzle pieces that you’re not sawing, so you don’t lose any. If you don’t want to have to solve the puzzle once it’s cut, assemble the cut pieces as you go, or at least put them down in the correct orientation, like an exploded diagram.
 
Some of the cuts are quite demanding, even with a powerful scroll saw and sharp, coarse blade. It’s important to keep a firm grasp on the puzzle pieces, which gets harder as they get smaller. If the blade binds, shut the saw off, free it and try again.
 
Some scroll saws have an adjustable foot to keep the work from being carried upwards by the blade. While effective for material of even thickness, they are more of a hindrance when cutting small puzzle pieces, especially in stage two, when the thickness will vary. If you have difficulty holding small parts, or are uncomfortable getting your hands close to the blade, try using a small wooden handscrew clamp to hold the puzzle piece. This is a trick I use occasionally.
 
Once a piece is cut in half and the thickness reduced, you may wish to switch to a slower-cutting fine blade for better control. If your saw has variable speed, you may also wish to reduce speed.
 
Jigsaw blades are inexpensive and are sold in packs of 12 for a reason – they are disposable and should be replaced frequently. Signs of a dull blade include a decreased cut rate and burning. Anticipate wearing out a blade after cutting about 100 jigsaw pieces of soft maple. If a blade binds and gets kinked, it should also be replaced.

 

Cutting the puzzle

For your first 3D jigsaw puzzle, a 1"-thick piece of wood about 4" square is a good start. Though I cut a 6"-square puzzle for this article, the process is exactly the same. Draw a 1" grid on one face.
 
Each jigsaw edge is cut the same way in seven steps:
  • Start the cut on a gridline, cutting along the line. We will call this 0°.
  • When you are one quarter of the way towards the next intersection, swing the material 100–200° counterclockwise in a fluid motion to start the knob.
  • Swing the material the clockwise to get back to 0°.
  • Cut straight just a little so that the neck of the knob won’t be too thin.
  • Reposition your hands and swing the puzzle 100–200° clockwise.
  • Rotate the puzzle counterclockwise back to the grid line, cutting at 0°. Ideally you get back to the grid at around the three quarter mark. Follow the grid line until you reach the next knob/socket.
  • Continue this process until an entire strip has been separated from the puzzle.
 
For our 3D puzzle, we are going to start by reducing our puzzle blank into a series of strips Each strip should be approximately 1" wide - any thicker will be harder to cut in the next stage.
 
Work on the far left row, and follow the seven steps for each square on the grid. Then saw another strip. Mixing up the orientation of the strips (north/south vs. east/west) makes the puzzle more challenging to assemble.
 
When you’re down to a handful of strips, you have to decide how challenging to make the puzzle. The seven steps to cut the pieces remain the same; only the sequence of cuts and orientation of the material changes.
 
Easy: you can simply cut each strip into individual puzzle pieces, following the grid lines that run across the strips. In my case, this will yield a 36-piece puzzle.
 
Medium: to increase the difficulty and number of pieces, cut the individual pieces for the easy version, then turn each piece on edge and cut a knob/socket in this orientation. In my case, this separates each piece into a top and bottom, resulting in a 72-piece puzzle.
 
Moderate: Turn each strip on edge and cut a knob/socket in each puzzle piece along the strip, separating it into a top and bottom strip. Flip each strip back to its regular orientation and cut the strip into individual pieces. This also yields a 72-piece puzzle.
 
Hard: Alternate between edge- and face-up cuts. You can continue splitting pieces as far as possible, based on the material left to work with and your skill level with the saw.
 
Cut Strips Off – To start, Wong marks a grid pattern onto the upper surface of the workpiece, and then cuts strips off it.
 
Helping Hand – A clamp will help secure smaller workpieces so that cutting them is safer.
 
Part Way Done – With the puzzle strips complete, you have to decide how intricate you want to be. An easy approach is to just cut the puzzle pieces from the strips, though there are lots of options for more difficult-to-assemble puzzles.
 

Fun variations

For a more interesting wooden jigsaw puzzle, try moving away from a straight grid and cut curved pieces instead. Keep in mind that curved pieces are tougher to balance on edge for stage-two cuts.
 
To make a borderless puzzle, start by cutting knobs and sockets around the perimeter and discarding the offcuts before cutting the actual puzzle.
 

Finishing

Once the puzzle is cut and reassembled, sand the surface with a random orbit sander up to 220-grit abrasive to remove any burrs, layout marks or rub marks.
 
You may choose to apply a design to the surface with paint, pencil crayons, heat transfer, pyrography, or some other method. Or you may choose to leave it to Mother Nature, with wood grain and colour as the only hints.
 
3D Puzzle Pieces – One option is to cut the strips on edge, turning the project into a multi-layer puzzle.
 
Final Cuts – With the puzzle cut into two layers, it’s time to cut the individual pieces out. Be careful not to create pieces that are too weak, as short grain can be your enemy.
  












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