Centerfinding Circle Template

When band or jig sawing an interior contour, some of the radii can be more accurately bored out before sawing. One of the problems of using this approach is finding the center point for the drill. Drafting circle templates show the outside circumference, but not the centerpoint.

To solve that problem, I made a template out of '/«"-thick clear Plexiglas. First, cover the Plexiglas with masking tape and lay out the hole sizes desired with a compass. Then lightly punch the center point of each circle with an awl and strip off the masking tape.

Using dividers, scratch each of the desired holes in the Plexiglas to a depth of several thousandths of an inch. The divider points should be very sharp and the engraving should be done by a number of passes instead of trying to do it in one or two passes.

After all the holes are engraved, drill the center holes large enough so that your scratch awi extends about VW through the template. Then work some black paint (I used model enamel) into the grooves so they can easily be seen.

To use the template, select the hole size that corresponds as closely as possible with the contour of the cutout. Lay the template on the workpiece and align the circumference of the selected hole with the contour. Then mark the center and drill the hole.

MARK CENTERPOINT WITH AWL v

This template is useful anytime you know the outside circumference of a hole, but not the centerpoint. It's also handy for finding the center of dowels.

John C. Walter Columbus, Indiana

Editor's Note: / made one of John's templates, and find it useful. When making it I engra ved the first couple circles with dividers, bid found it hard to hold the dividers steady and scratch deep enough. For the rest, I switched to a Forstner bit mounted in a drill press. Spin it by hand just until the rim scratches the Plexiglas and produces the circle, but stop before the lifter starts cutting.

Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

Get My Free Ebook


Post a comment