This band saw circle cutting jig is great for making perfect circles every time. It features a cool adjustable sliding t-track which enables you to easily change the size of your circle, it also has a nice clamp as well as a built in measuring tape to easily set the size you want. The jig is sturdy and you can make a variety of different circles with different types of wood safely and easily. Let's go over the steps of how to build it!
Step 1: What You'll Need:
For this build you're going to need the following:
Wood: 1/2 " (12 mm) Baltic Birch Plywood
- A) 1 @ 19 x 15 x 1/2" (483 x 381 x 12mm) - main board
- B) 1 @ 10 x 15 x 1/2" (254 x 381 x 12mm) - top side 1
- C) 1 @ 7 x 15 x 1/2" (178 x 381 x 12mm) - top side 2
- D) 1 @ 2 x 15 x 1/2" (50 x 381 x 12mm) - main track
- E) 1 @ 1 x 18 1/2 x 1/2" (25 x 470 x 12mm) - bottom miter t track
- F) 1 @ 2 x 15 x 1/2" (50 x 381 x 12mm) - bottom back stop
- G) 2 @ 2 x 2 x 1/2" (50 x 50 x 12mm) - knob
- 3/4" Screws - 20mm
- 1 1/4" Screws - 30mm
- 1 @ 1/4" dowel 6mm, cut to 20mm
- 1 @ 1/4 " pronged tee nut
- 1 @ 1 1/4" bolt 15"
- Seamstress measuring tape 381mm
You'll also need, some glue, contact cement, wipe-on-poly and wax polish.
Step 2: T-track
Let's work on the t-track going into the band saw, cut E.
I'm setting up the router with a 1/4 inch straight cut bit and I'm routing out 1/4 inch up, with 1/8 inch in on each side to create the t. You want this to fit tightly in the t-track on the bandsaw, so it's better to make it a touch too tight, and then do some sanding to make it fit perfectly.
Next up I need to make a very shallow dado, the width of the top of the t, in the main board, cut A where it will slide and be attached to the track. Mark out where exactly the track needs to go on your main board, this will depend on what bandsaw you have. Make a series of very shallow cuts, about 1/16th of an inch on the table saw.
Then turn it over and clean it up with a chisel.
Step 3: Attaching the Track to the Main Board
Next up I'm countersinking some holes on the bottom t-track. I'm screwing it in on the main board, fitting it into the shallow track, and testing to make sure it fits. Mine was riding a touch high, once I rode it in the track on the band saw, so I removed the track from the main board, and cleaned up the dado a bit with a chisel. You want a really good fit here, so it's a good idea to take your time to ensure it rides perfectly. Once I had a good fit, I glued in the track, and screwed it down again. You want to make sure the screws are countersunk well so they don't scratch the track. Of course, tightening by hand is a good idea too.
And then checking again by putting it in the track on the band saw to make sure it fits well.
Step 4: Knob
Next up we have the knob, so glue the two small pieces, cut G together. Then create a knob, I used angle bisecting. I drew the bolt head on the knob, chiseled out enough space to fit it in, and then cut out the shape on the bandsaw. Next, I epoxied in the bolt head and let it set up.
Step 5: Sliding Center Track
Now I'm marking out where on the board the blade is. This is where the sliding track will go and I've also marked out the sides of the center piece on the main board.
To make a t-fit here, I'm using the router again and cutting about 1/4 inch on the sides of cut B & C, as well as both sides of the center track, cut D. You might have to check the pieces fit together well and maybe do another shallow pass to make everything fit nicely. Try it out, with the track slider in the middle, held in place by the t-tracks on both sides.
OK, mark out about 1 and a half inch in on the track slider in the center. Drilling a 1/4 inch hole, then hammer in the pronged t-nut.
Step 6: Attach the Side Pieces
Then align the center slider, cut D, clamp it down, and fit the side pieces. First predrill several holes in both of the side pieces, put them back in place and screw them down. Then take the screws out, put down some glue and screw the boards down again. It's important to screw in first, so you establish the holes before gluing, because it makes it a lot easier to line everything up, or else the glue has a tendency to make everything move, now the screws can find the existing holes a lot easier.
Next, remove the center slide, and you want to make sure you don't get any glue on that. I put a mark in center, 1 1/2 inches in, and then I drilled a 1/4 inch shallow hole. Also, mark a line accross the hole with a pencil because it will make it a lot easier to line things up later if you have that mark. Then, glue in the dowel.
Step 7: Stop Block
OK, now let's attach the stop block, cut F on the side. Make sure to countersink, and I'm using some 1 1/4 inch screws here.
Next I'm sanding down any burrs, getting everything nice and smooth.
Step 8: Measuring Tape
Now, in order to attach the measuring tape, it's a good idea to create an indention so it can lay flat. So mark out the width of the tape, and I'm putting it right up on the edge next to the sliding track. Mark it out with a knife, use a framing square and make sure to get a good groove created with the knife. Next I'm using a shoulder plane, however you could also take very shallow cuts on a table saw, or use a chisel. Once the groove was just deep enough to let the measuring tape lay flat, I put on contact cement on both surfaces, waited about 40 minutes, and then attached.
Step 9: Finishing
To give the jig some protection I'm using wipe-on poly, and I will add many more coats since I will be keeping the jig outside. I'm also putting on some wax polish on the track on the jig, as well as on the saw itself. And on the saw I'm using mineral wax polish here to protect the metal. The wax will help the track glide nicer.
Step 10: Cutting
OK, now let's try it out, slide the jig in place and screw in the knob from underneath.
So let's cut a circle. So first of all, we need to drill a shallow 1/4 inch hole in the center of whatever we want to cut. Then find the dowel and match them up, and then we start cutting. So push the jig all the way in until it hits the stop, and then start spinning the board. We can change how big we want to make a circle simply by releasing the clamp and moving the board to whatever size you want. For example, if you move the slider to 3 inches, the circle will be 6 inches in diameter.
Step 11: Sturdiness
Because the center sliding track has a t-connection, it's very stable and doesn't pop out easily, it only slides horizontally, and doesn't move vertically. So you can move it quite far out, secure it and make a rather large circle without any difficulty. Using the jig, I could create a circle up to 28 inches in diameter, but theoretically you could modify it to cut circles of any size, as long as increase the size of the whole unit.
Step 12: Conclusion - Watch the Video
For a much better perspective on how to build this jig, please check out this very concise and detailed video which includes all the steps of building this jig.