Any tips on making the last bit of a cut with the Jasper circle jig on a plunge router, except to be careful? When the circle is finally cut through, there is no guide remaining to keep the router cutter in its groove, and it could gouge the outside of the cut, the good part.
Everyone knows when making concentric cuts, like the tweeter cut-out, make the outer cut first, then make the inner cut? If the inner cut is made first, your center guide is gone! (I learned this years ago cutting gaskets.)
For what it's worth, I do holes a little bit different way. I cut holes with my Jasper on top of a large scrap of mdf. Just drill a hole the right size for the jasper guide pin, it needs to be tight not loose, pressfit the guide pin into the hole with a small mallet, you want it solid. I also predrill the center guide holes all the way through on whatever baffle piece I am going to make holes in.
To make the hole I insert the pin in one of the predrilled holes in the scrap, set the baffle center hole down over the pin, or you can put the pin in the baffle and press fit it down into the scrap hole, it doesn't matter.
I also have some small ~ 1" wide strips of 1/4" and 3/8" scrap premade (use whatever you want as long as it isn't thicker than whatever you are making holes in). I use them to secure the 4 sides of the baffle to the large mdf bottom board. So what I end up with is basically a "jig" that holds the baffle from moving in any direction, with a pin hole through the hole to be drilled that is securely stuck into the bottom mdf as well. Those scrap pieces are tacked into the large bottom board, not the baffle piece.
You can guess what comes next, you route holes in the normal way (outside to in} more out of habit rather than need. The only thing to keep in mind is that you need to keep the rig/router pressure flat on the outside of the holes and not put pressure on the cutout piece as you make your holes (that cutout isn't very solid after it is no longer attached). This will work if you make the inside hole first then want to make a countersink. I suggest using an appropriate extra scrap round hole piece around the pin to keep the pin from moving, the one leftover from making the hole the first time works good. You can use this method to make countersinks deeper if you need to after you have the holes already made as well. It is important to make sure the baffle does not move at all in relation to the guide pin and that the guide pin also does not move whether there is something holding it or not for this to work.
I should have mentioned that there is nothing "magic" about the jasper pin that comes with the jig, any old drill bit the same size will work for thicker pieces.
There's a lot of experienced folks here so I know I am not the first to do this, but maybe someone reading hadn't thought of it yet. I tried to write it up as clearly as I could so its a bit verbose.
