You can use your router and pattern jig, but then you need to make a separate pattern for each woodworking project. It seems all the options are cumbersome.
WHAT ABOUT A SIMPLE JIG THAT MAKES GREAT CIRCLES EVERY TIME?
Photo via Wooden-Box-Maker.com
HOW DO YOU MAKE A CIRCLE CUTTING JIG?
It’s really quite simple.
Begin with a piece of 1/2″ or 3/4″ plywood (or MDF) that covers your bandsaw table with an inch or so overhang. The size isn’t essential. My table is 15″ x 19″ so I cut the plywood to 16″ x 20″.
START WITH THE BACK
Attach a slide to the back of your plywood base. You want it to fit your miter slot so you can easily slide your base into the blade with wood on either side. I used a piece of plywood for my slide so I wouldn’t have to worry about seasonal movement. I cut it on my table saw to fit my miter slot then screwed it to the back with countersunk screws.
With the slide in place, feed your base into the blade and stop about halfway through (see photo of finished jig). Then add a block to the back of the jig to act as a stop so you can’t cut further than this point.
That’s it for the back.
MOVING ON TO THE TOP
With your saw off, put your jig back on the table and slide it in until it hits the stop you just made. Mark a line at the front of the blade and extend it perpendicular to the blade, to the side of the jig as seen in the photo below.
Now, remove the jig and route a groove, centered on the line you just made, from the side of your jig to the spot where the blade stops.
I used 1/2” plywood for my jig so I made the groove around 3/16” deep x 3/4” wide. If you want, you can mark some distances from the blade on your jig.
Make a slide to fit into that groove long enough to just overhang the edge (to make it easier to grab). I cut a piece of wood 3/4” wide and sanded it to a smooth fit.
Make sure your slide is flush with the surface of your jig. Your workpiece is going to sit on top of the jig and you don’t want the slide to interfere.
Finally, drill a hole for a pin in the end of the slide. I used a 1/4” birch dowel, but if I were to do it again, I’d use 1/8” metal dowel because it is smaller and stronger. You need 1/4″ or less protruding above the surface of the jig.
Make sure your slide can glide in and out smoothly. That’s it. You’re done.
To use your jig, set the pin to the radius of your circle and put a hole the size of the peg on the back of your workpiece. Fit your workpiece over the pin and carefully feed it into your blade.