A CNC lathe made from plywood

BobsCNC Revolution

- Ken Burton

Over the past few weeks, I've been having a lot of fun setting up and exploring a CNC lathe. I'd been toying with the idea of adding a 4th axis to my flatbed CNC router when I came upon the Revolution from BobsCNC. Even in the CNC world, the Revolution is a unique critter. Instead of being an add-on accessory, this machine is a dedicated computer-controlled lathe. And instead of coming as a plug-and-play, steel and aluminum tool, the Revolution arrives in kit form, primarily made of plywood. After giving the matter some consideration, I decided I was up to the challenge the kit offered.

All of BobsCNC kits are similarly designed with laser-cut plywood pieces bolting and slotting together, much like an Erector set combined with Lincoln Logs. While you'd think that 14" plywood wouldn't be stiff enough for such use, the clever engineering behind the way the parts fit together yields a remarkably rigid assembly. By building their machines this way, Bobs can offer more capacity at a lower price than their competitors.

The rub is that you do have to put the kit together. I spent about 12 hours over three days assembling the Revolution. It wasn't a difficult build, but there are just a lot of parts to assemble and bolts to tighten-among other things, the hardware kit included a bag of 300 M4 x 16 machine screws and a matching bag of M4 nuts. These are the primary connectors used throughout, and there were only a few left over at the end. The online assembly manual ran about 150 pages. I opted not to print it out, although that might have made things easier as I had to scroll up and down a lot as I worked. The instructions were mostly clear, though there were a handful of places where some of the hardware was misidentified and at least one place where the bolt count was wrong, which left me puzzled for a few minutes.