More as a novelty than an actual need, I made this to get the nut started (and finish taking it off) of the arbor on the table saw when changing the blade. Although the title says “wrench”, it can’t loosen or tighten the nut.

I’ve been thinking about this for several years – every time I change the blade it comes to mind that I need it and so I’d think about it some more. The challenge is to make it slim enough to fit and also long enough so that I won’t have to crank the blade all the way up. Over the years I considered a few different mechanisms, including a belt drive, but settled on a series of gears (much like my gear connected twin screw vise) to extend the reach.

When I started making this just two days ago, I only had a rough idea on how it would be done, and basically designed as I went. First parts I made were the gears:

I used Matthias Wandel’s gear generator to design and print the gears, then glued the print to a piece of Baltic birch plywood.

The one at the end needs a hole for the nut to fit into and I drilled a 1″ hole to start and removed the rest with a chisel and round file:

The nut should be a “grippy” fit, not too tight and not too loose, so it will stay in the hole without falling out while getting the wrench in position.

Here I’m using one of my newly minted power wedge clamps to hold the piece of 1/2″ Baltic birch plywood while I route out the recesses for the gears:

Originally, I was not going to do it this way, but decided it’s doesn’t take much more time than cutting it out in layers. Note the integral axles for the two centre gears:

Here’s how they look in place and turning freely:

If I were to do it again, I would have added one more gear to extend the reach. Also, having five gears would make the ones on the ends turn the same direction.

Shaping the handle and smoothing the curves on my homemade belt / disk sander:

Here’s the winding crank on the back. The dowel turned out to be unusable, since the crank itself is too small – I just use my fingers to turn the crank as shown in the video at the end of this page:

To complete it, I cut a piece of 1/8″ plexiglass and screwed that on as a cover. It also holds the gears in place and lets you see them:

After all, what’s the point of making wooden gears if you can’t see them?

Here’s the build video with a quick demonstration of the device in action at the end: