Router jig finishing off
The last couple of steps for making the circle cutting jig was to drill some holes to mount it to the base of the router. I found I needed to counterbore the holes here as the screws were not very long.
I also added a sheet of polycarbonate to the base to lift it up a little to compensate for the thickness of the pivot, to give a smooth surface to slide the router on and to ensure the screws were below the surface. I’ll smooth off the outside once the glue has dried.
I ordered some bolts for the pivot but found out I’d got the wrong size once they arrived, I needed an M6, not an M5, so some replacements are on order. Although I do have a long screw I can use in for testing. My dad commented that I could have made a much simpler setup using a nail for the pivot, which is what April does in the video on my first post. I did think of that but was worried that the nail would come out whilst I was cutting the circle. I also have 2 different sized holes to cut so some kind of adjustment is useful; although a second nail hole might have worked too.
To make the bolt easier to fit, I made a handle from some hardwood that I rounded off then used a gouge to add some grip. I drilled through the handle and fitted a threaded insert.
So the jig is ready for some test cuts. I used the scrap ply from the pallet that was provided with my benches. Perhaps over-thinking the solution here but the doors would be very expensive to replace if I get this wrong.
Next step, using the jig.
Posted in: Circle Jig
Metal sculpture in brass, mounted on an 1800s French Coin
If you’re worried about the final cut, why not use the jig to cut a template out of MDF? Make it oversized by the right amount to use a guide bush on the workpiece. The risk with these circle jigs is when you complete the cut, the pivot is secured to the offcut which is suddenly loose – this can result in nibbling a bit more out of the workpiece than you want.
If you make a template first, there is no way the router can cut into any part of the workpiece that you want to keep. If it comes away from the template edge, it just cuts more out of the offcut and another pass will tidy it up.
I did look at this as my first idea. The problem I have is securing the template to the door. I don’t have any clamps that would reach from the edge of the door, although I could make the template in the middle of a large sheet to resolve that issue.
The trick with the circle jigs I’ve been advised is to leave short sections uncut, like the sprue on a model. These support the offcut and pivot. Once you’ve gone all the way around then you can use a saw or chisel to knock through the tabs.
Double-sided sticky tape is all you need for sticking a template to a workpiece. Just a couple of square inches is enough to handle the small shear forces of you pushing the router against the template.
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