DIY Balance Board

I've been using a stand up desk for several years. It's done wonders for my lower back, which was in rough shape after endless hours of sitting during grad school. Still, I find a few aches and pains from standing stock still (knees locked) all day. After a bit of digging online, I found several articles which suggested using a balance board (also known as a "wobble board") as a way to keep myself in motion whilst I break rocks at the data mine.

These boards are not expensive - I found several that would probably work in the $20-30 range. Still, why buy it when you can make it, eh?

This is an exceptionally simple project. Given the proper tools (I go to our local Tool Library, a very affordable sort of community maker space), it can easily be finished in a few hours or less.

I had some 3/4" FSC-certified plywood leftover from another project, and picked up the softball for $5. That's all you need, though I chose to set the finished board on a small rug, and cover it with another.

I made the disc as large as the plywood scrap (24-in). The Tool Library already had the circle jig, but since it was built for a different router base, I essentially ended up building a new jig. There are several very good videos on how to do this on YouTube - it takes little time, and can be made from scrap wood.

To center the jig, I tapped a small nail where I wanted the circle center (measuring 12-in from side and bottom of the plywood), then cut off the head with pliers, leaving a sharp point for marking the underside of the jig. I then extended the straight router bit so that I had my outer point for the jig, centered the jig arm over the nail, and tapped a couple times with a rubber mallet.

After pulling the nail, I drilled holes through both the plywood and the jig arm, and attached the jig to the plywood with a bolt and loosely fitted wing nut. After making one shallow pass (to reduce splintering), I followed up with one 2/3rds the depth of the plywood, and then a final full-depth cut to cut the disc from the plywood blank.

A regulation softball is roughly 4-inches in diameter at the seams. The largest hole saw we had available was 3-inches. After cutting the 3-inch hole (in two passes, one from either side to limit splintering), I used a 45-degree chamfer bit to "widen" the hole from the underside. I also used a round-over bit to put a curved edge (both top and bottom) on the disc itself.

It's really just that simple. The whole project took maybe two hours, and that included stopping at the store to buy the softball. I haven't used the board a great deal yet (though I'm standing on it as I type this 'structable), but if it ends up giving me leprosy or somesuch, I'll post a disclaimer here. So far, my ankles are getting much more of a workout than I'm used to, but my knees are flexed. That's got to be a good thing, right?