Cutting circles

Above, my jig for cutting circles on the bandsaw. That is a 3 inch diameter circle being cut, and I've used it to cut octagons into circles for "tondo" frames, of 50 some inches in diameter.

Above, showing the the brass plates that slide under the fence, holding the jig in place. The two bolts act as adjustable stops, depending on blade size and position.

This image shows the bottom of the jig. The strip that rides in the miter slot of the saw, and the thumb screws that hold the sliding piece that adjusts for the size of circle desired.

Here, the jig is lined up with the blade of the saw, and the brass pin that the stock is centered on is visible. A hole is drilled in the bottom of the stock, as in the top photo, or, in the case of a tondo, a cross piece is screwed to the frame, and a block the same size as the frame is added for the machining operations, see below. The sliding element is positioned with the pin at half the diameter needed, stock affixed, then the jig is slid into the moving blade, and against the stops. Once stopped, the stock is turned into the blade.

Above, a tondo in process. The same pin hole is used to rough cut the tondo on the band saw, as well as a guide for a router.