I am trying to make some 4 section trays to give as xmas gifts and I am trying to figure out a way to get them to be perfectly circular. My original idea was to draw a line to be the outside edge of the circle, then bandsaw and sand up to it, but I tried it and the results weren't very good.
I also thought about using a circle jig on the bandsaw, haven't tried that, but I don't think it would be as good as I could do with a router.
What I think I would like to do is first bandsaw staying close to but outside of the line, then use some sort of a jig combined with a router and a straight bit to do the final trim. I think this is probably as close to perfect as I can realistically hope to get.
Now my question is how to go about doing this. Most of the circle cutting jigs I have seen want you to put a hole for a guide pin in the work, but it seems like those are designed with the inside of the circle being the waste piece. In my application, the inside of the circle is the part I want to keep. I know I could flip the workpiece upside down and drill a shallow hole there, but I'm not sure how to go about getting it exactly centered.
I know you can use a square to find the center of a circle, but that requires you to have a perfect circle to start with. I also know I could start with a square blank and mark the center on both sides, but the template that I'm using doesn't have a center marker, so I'm not sure how to go about getting the template exactly centered even if I know where the center of the workpiece is.
So my thought about how to actually trim the circle is to just use a simple piece of MDF about the same length as the diameter of the circle. I would drill a hole at one end and mount the router so the bit protrudes through that hole, then use a pin to attach the MDF to the center point on the workpiece. Then plunge down and work all the way around. Am I on the right track?
Any info or suggestions on any of the questions I asked would be much appreciated.