Gizmos and contraptions: When woodworking and engineering cross paths
My nine-year-old son was learning about gears in his science class, so I told him we should try our hand at making a few plywood gears to see how they worked. He already knew about “driven” and “driving” gears, and how different-sized gears affect how fast other gears connected to it rotate. This was a great excuse to head to the shop and practice woodworking techniques while making something cool.
Probably the most famous Canadian woodworker/engineer is Matthias Wandel. If you haven’t heard of him, or seen any of his videos, go to WoodGears.ca. You’re in for a treat. Between being amazed at what someone can do if they set their mind to it, you’ll also have an occasional laugh. Although Matthias has a pretty dry delivery, he’s got a good sense of humour that comes out when you’re least expecting it.
One of the cool things about Wandel’s website is his “gear template generator.” You can enter the diameter of the gear and number of teeth, along with a few other bits of info, and you have a printable diagram of the gears.
Careful Curved Cuts
Jonas carefully cut the teeth on our first gear on a scroll saw.
Paste Them On
We used rice glue to paste the gear templates to plywood, but a kid’s glue stick, or even a very light layer of white or yellow glue, will also work.
To the shop!
Once we printed out a few gear templates, we headed to the shop to cut them out and put them together. We only had time for two gears, but that would give us a good idea of how it all worked. After pasting the template onto some 1/2″ plywood, my son and I split up the work. He cut the small gear on my scroll saw (he likes to call it a squirrel saw, for some reason) while I cut the larger one on my band saw. A file and sandpaper smoothed some of the imperfections before we drove a nail through the center into a strip of MDF I had lying around. Worked like a charm, which brought big smiles to both our faces. Neither one of us had a clue what it was, but it was cool to see the teeth meshing nicely while the gears spun.
Two more gears
The next day we had a bit more time so we tried our luck with a pair of 90° gears. This was my son’s idea, but I thought it would be a good little challenge for us, too. We worked off Wandel’s gear templates, but offset each of the tooth lines by a good 1/16″ because of the fact that the sides of each tooth needed to be angled.
With both gears complete, we installed the first gear so it meshed with the first two gears we made the previous day, then I added a second piece of MDF at 90° to the first piece, and backed it with a piece attached at a 45° angle. A bit of fussing with exactly where to attach the fourth gear, and we were done. All four gears spun when one of them was rotated. Plywood can be a bit splintery, and that caused the gears to catch a little bit, but with a bit more sanding and filing, things worked pretty well. And the more the gears rotate, the smoother the action becomes.
We still had no idea what this contraption was, but we both knew it was pretty great. I’m still trying to dream up a practical use for a bunch of wooden gears that a nine-year-old would find interesting. If you have any ideas, don’t be shy. He wants to build a rack and pinion gear next, which will open up the possibilities of what can be done.
A few examples
If you’re new to Matthias Wandel, check out these few videos first. If you’ve read my earlier weekly columns you might remember I’m building a marble run in my shop with my son. Matthias also built a marble run. Here’s a good video to introduce you to Matthias’s approach to woodworking and engineering.
Our First Set – These two gears came together quite nicely and worked pretty well.
Four in a Row – We attached the third gear, which has angled teeth, then fit and attached the 90° gear.