Accurately: with a 1/8" up or down spiral bit in the circle routing insert: 82mm or 3 3/16" diameter.
Not accurately: With a 5/16" template guide held next to the side of pivot guide with a 1/8" up or down spiral bit: 23mm or 7/8" diameter
Tim
I have to make several small circle cuts ranging from 72mmm - 94mm, accuracy counts. I am considering the MFS 400 or the circle gig from Micro fence. I believe the MFS
may be a more versital tool but the Micro Fence with the lift kit will be accurate and repeatible. I needed some input from someone who was familiar with the MFS 400
I love my 400! I hardly ever use it for it's intended use - with the router. It's a perfect oversized square and it also acts as big flag stop for making repetitive cuts on my MFT. I simply butt it up against the fence and use a quick clamp to hold it in place where I want it. I can think slide my stock under the rail and butt it up against the MFT and quickly make several identical parts. Don't know what I would do without it.