N-Compass Router Jig 
The N-Compass router jig is a precision compass tool designed for cutting accurate circles and arcs. It has the ability to cut a range of diameters from very small radii to very large radii, simply and hassle free.
The router attaches to the compass jig using its base plate guide rod holes. The cutting radius is set using the router base plate's guide rod locking pins which can then be finely tuned using a Vernier micro-adjuster.
How many different ways are there to cut a circle? Too many, and most
of them are time-consuming, require quite a few steps, and the
sacrifice of a substantial amount of material. Even the most obvious
non-router technique (rough-cutting a circle with a jig saw and then
using a jig with a belt or disk sander to true-up the edges) is
surpassed by using circle template with a pattern-following or
flush-trimming bit, so why not just cut the primary circle with the
router and get that crisp, finished edge in one step without all the
hassle? The answer before the advent of the N-Compass would have likely
been "because by the time I waste the time and a piece of wood to make
the trammel arm I could do it more efficiently another way," but not
now. It's not uncommon to have the N-Compass installed on the router
and set to length in well under a minute, and without dulling your bits
and blades!
We also carry the excellent router guides by Jasper Tools:
