Clean & smooth inner cut on MDF rings?

[xenergyx]

I picked up my first sheet of MDF today for my kickpod project....

I was lucky enough to find an approx 4' x 4' scrap piece of 1/2" MDF lying around at home depot and picked it up for $1.09 Saved myself from spending around $20 on a 4x8 sheet that I could never fully use...

I cut out 4 circles and made the outside cuts fairly clean with only 1-4 bumps on each edge...

But when I tried to make an inside cut (with only the circle, my router, and a homemade jig) the cut was entirely bumpy and a lot harder to cut...

The only way I found to cut the inside circle is to secure the router upside down and slowly spin the circle while it's still attached to the jig... Is there another way?

I'd like the cuts to be smoother but if that is the only way then I'll just cut the rest like that and sand them down...

Here's a pic of what I am talking about....



I ran a file around it to smooth it out some just so I could see if my speaker grills fit it... You can see the small grooves that the file made, and how there are pits with no grooves in them...

[cam2Xrunner]

Looks good enough. Just make sure to use some type of gasket material between the mdf ring and the speakers, to make a seal.

[xenergyx]

good call.. thanks.. I probably wouldn't have thought of that...

I figure now that it wont even matter what the cuts are like, because I forgot to compensate for carpeting on my ID...

I think when I get to that point I can just extend the carpet past the ring to where it lines up to the grill and it will be fine...


Now I just gotta figure out how to cut a circle with a radius smaller than that of my router's mounting bracket...