How to remove rear seat and plastic???

[BlacknRedGT]

Well Im trying to make a 45 degree angle on the edge of my 3/4 mdf board to finish my box. Sounds simple and I got a 1/2 inch bit for my router but it doesnt seem big enough to cut that angle all the way through the 3/4 mdf board. Any ideas or am I just going about this all wrong???

Couldnt really find a good forum for box building so hopefully someone knows here.

[dangus]

I would find a way to position another sheet or board at a 45 degree angle, then use a plain 1/4" carbide bit to trim the edge. (So the finished edge is parallel to the bottom of the cutting bit.) My router is equipped with a large base plate that I made from thick clear plastic; this might be very tricky to do with a normal sized base plate.

Since you presumably need to trim at least 16 edges (if you're doing 2 speakers), the jig needs to be pretty quick and easy to set up. I think I'd cut a couple of triangles or bent L shaped pieces with a 135 degree angle. Screw/glue them to a spare sheet of MDF, which is clamped to the work bench. Then clamp the boards to be trimmed to the 135 degree things, and trim the edge down with the router.
Here's a terrible sketch, which may make things clearer. If you slide the router to the right, the bit will chew off the edge of the board at the correct angle. (This working-over-the-edge technique can be used to trim box panels flush, if you put a spacer sheet of MDF under the router base. The trick is to adjust the cutting height very precisely.)

[BlacknRedGT]

Thanks for the help. Something so easy tends to get complicated pretty quick. I guess I just need to take the extra time to set everything up right exp when I will be doing it again. Maybe I should of just made a square box my first time around.