Over Head Pin Router?

[mashtun]

I keep seeing these go up for sale, not that I can afford on, but what exactly is it? I see pictures, but can't quite get my head around what it is supposed to do.

John

[MikeMcCoy]

Here's the definition from Lee Valley.

Essentially, pin routing uses stationary pins to guide a template, which is mounted to the workpiece to be routed. Because the rotating bit does not come in contact with the template, templates stay accurate and can be used over and over again. Pin routing goes further than just making it easy to copy items; it also simplifies the process of making templates, inlaying work and making relief or incised signs.