Lee Valley's cornering tool is more accurate than sandpaper and quicker than setting up a roundover bit in a router
In the couple of years since I picked up Lee Valley’s cornering tools, they’ve become an indispensable part of my everyday toolbox. I use them to round over sharp wood edges, but they’re more accurate than sandpaper and quicker than setting up a roundover bit in a router.
The set comes with two tools: a 1/16-in. and a 1/8-in. radius edge ($25); each tool also can be purchased separately at about $15 apiece. The tools are about the size of a small screwdriver and are essentially small hand planes with a curved blade that you pull along the edge of the wood. As with any chisel or plane, success with the technique comes in how you angle and tilt the tool as you use it. Finding the sweet spot yields a consistent, near-perfect roundover. Also, as with any chisel or plane, reading the grain makes all the difference; pulling against the grain with the cornering tool, especially on open-grained woods like fir, is liable to lead to some major tearout.
These tools excel at getting into tight spaces where even trim routers won’t fit. I also use them when working high up on a ladder where I’d rather not have both hands holding a router.
Because any blade is only as good as the sharpness of its edge, it’s important to keep the blade honed. Lee Valley includes instructions and a small piece of fine-grit sandpaper to help the process. A few passes with the sandpaper wrapped around a dowel is all it takes to tune up the blade.
I recommend that any finish carpenter pick up these tools. Even if only used once or twice, they’ll easily pay for themselves, but I bet you’ll find yourself using them a lot more than you think