Make countersink deeper?

[st33n]

Yesterday I made my speaker holes. They worked out great, only the countersink should be 2mm deeper. As I now no longer have a center point, I cannot use my circlejig to align the router.
How could i make the countersink a little deeper so my woofers align nicely with the wood?

[Enzo]

Use a router around the edge of the hole?

[st33n]

Wont that damage the circle?

[dagerman]

If you still have the cutout you made yesterday, could you put your baffle on a piece of scrap wood and clamp it down, then place and center the cutout in the opening, making sure that it is center and secure it to the scrap piece with two countersunk screws? This should give you a flush surface with the center hole you need to do a second pass with the router, no?
If you don't have the cutout piece anymore, any piece of wood that fits inside the cutout should work, if you mark the center exactly and drill a hole for the jig pin.

[dangus]

What dagerman said.

Or, there are router bits that have bearings at the end. If you had one the right size and shape, you could just run that around the inside of the existing cut-out. Considering how big the bit would have to be, a half-inch shaft (and router) might be advisable.

[mightydub]

been there, did what dagerman said.

What dangus said will work also if you can find the right bit - needs to be a square cut bit with a bearing. I don't think you'll need a 1/2 inch shaft unless the countersink shelf is really wide.

[st33n]

I think I might have a bit like that. I am going to give it a go tonight. The width should not really matter, as I can do the inner part without damaging the edge.