Finds: Offset Ring Pattern Kit

Ever struggle to find something that was round laying about the shop so you could draw yourself a pattern for a hole — but whatever you find isn’t quite the right size? Try this offset ring pattern kit from MLCS.
The kit consists of a bunch of accurately-sized rings to serve as moving “shims” to adjust the size of your existing round “template” (read: paint can, etc.). All you do is stick your pencil in the center and roll the disc around the template — creating a perfectly resized new circle.
It’s a useful tool to aide marking a scribe line for fitting cabinetry to uneven or wavy walls, too. The rings themselves are made from non-marking brass and arrive in a plastic storage case. The kit includes 1/4″, 5/16″, 3/8″, 7/16″, 1/2″, 5/8″, 3/4″, 7/8″ and 1″ offset rings.
The kit goes for $21.95 on the MLCS site.
Offset Ring Pattern Kit [MLCS]
This is an example of a tool that would be really easy to make on a metal lathe in a hour or less.