The laser cutter is currently the only tool capable of making accurate circular cuts in wood. The laser cutter has its limits, however, as only thin widths of wood can be cut through. The jig saw, scroll saw, and router are capable of these cuts, but novice wood workers may struggle keeping the cut in line with the desired design. The circle jig created here is capable of solving this problem by adapting the bandsaw for this special cut. By securely spinning a work piece through the saw, a circular cut can be made in any desired wood with great accuracy.
The Circle Jig is able to be adjusted to desired radii depending on the desired result. Using a small pivot point on the end of an adjusting slider, the workpiece is rotated through the bandsaw to create the circle. Moreover, the jig can be clamped underneath the band saw to prevent any unwanted movement.
Step 1: Tools and Materials
- Impact driver
- Table Saw
- Track Saw
- Nail gun
- Tape Measure
- Speed square
- 3D Printer
- Laser Cutter
- Floor shear
- 3/4" Thick Plywood
- 1/4" Thick Plywood
- 1" Screws (4)
- 1/4-20 Screw
- Sheet Metal
- L Brackets
- 1" Nail Gun Nails (8)
- Wood Glue
Step 2: Make Measurements for Track Saw
The woods used for this project must be cut using the track saw to make manageable pieces of wood for the band or table saw. This must be done for the 1/4" thick bottom base of the jig and both 3/4" pieces creating the alley for the slider. Depending on the pieces available, cut another piece of the 1/4" plywood that will fit in the laser cutter.
Step 3: Cut the Base and Slider
Using the table saw, cut a 12 x 24" piece from the 1/4" plywood. Next, cut two 12 x 11.125" pieces from the 3/4" plywood. Moreover, cut a 1.75 x 15" bar from the 3/4" ply wood. This will be used as the sliding mechanism for the jig.
Step 4: Assemble the Base
Mark the middle of the bottom 1/4" thick plywood and measure .875 in each direction. Cover the two areas outside of this marked region with wood glue. Next, place the thicker plywood pieces on the wood glue. The slot for the slider should be apparent now. Using the nail gun, nail the plywoods together to reinforce the assembly with 3/4" in nails.
Step 5: Place Clamping Locations
Underneath the base, measure 3 inches down and 3 inches across from the back left and back right corners. Drill in the L brackets with 1" screws with the outside of each being position at the 3x3" mark.
Step 6: Cut Slot Through Slider, Attach Pivot Point, and Sand
Using the drill press, drill 2 centered 3/8" diameter holes an inch down from both ends of the slider. Take the slider to the router, and with the 3/8" bit, cut the slot down from one hole to the other. At one end, measure a half inch between the slot and the end of the slider, and shoot a nail through with the nail gun. This nail will act as the pivot point. After, sand the sides of the slider well until the slider can comfortably fit and slide through the base slot.
Step 7: Print Out and Build Slider Stop
Design a cylinder or small prism with a threaded hole for a 1/4-20 screw on SolidWorks. Print this out on a 3D printer. There is no need for a raft on this print, and print with 20% infill. Use the drill press to drill a hole through the end of the base slot, an inch from the back. Push the screw through the hole and attach it with a nut. Place slider on the base with the screw within the slot, and place the stopper on the slider with the screw in the hole. A clamp will be used to stop the slider when using the jig.
Step 8: Create Circle Jig Sign
First, design two 6x6" squares, one with the words "Circle Jig" on it and one without, on Illustrator. Laser cut these on 1/4" thick plywood. Next, cut a 6x6" square of sheet metal using the floor shear. Once these three pieces are made, drill holes in each square of plywood an inch across and a half inch down from the top corners, and punch the same size holes in the same location into the sheet metal. Layer these with the sheet metal in the middle, and attach to wherever you will store the Circle Jig.