How do you cut out shapes accurately?

[javeryh]

I'm making a panel which is going to act as a bezel and a marquee retainer so I need to cut three holes and they have to be perfect (one is a semicircle and the other two are rectangles).  I have a plunge router and a 1/2" dado bit which I'm going to use to make most of the cuts.  I only have a 1/4" flute cutter thing but I can't use it because I'm putting a bevel on the edge when I'm done cutting and my chamfer bit has a 1/2" bearing - this is why I have to use the 1/2" dado cutter - I'll have to make about 3 passes to get all the way through...  Anyway, I tried doing this last night and it came out OK but there were two spots where I "overshot" my mark so I have to recut everything.  Is there a method to this or should I just be winging it like I do everything else?   

[scotthh]

Good luck... At least when I wing it I don't get too mad that nothing lines up right. When I measure it and it's wrong  .

Btw, Between that thead and this (and beer), I feel less bad about f'ing up another 12' piece of crown molding...back to the Depot in again in the morning...

Oh, I don't have an answer for you question, but posting is part of my catharsis, hope you don't mind.

[Jdurg]

For the rectangles, have you thought about creating a pattern out of straight boards and placing it underneath the item you're cutting?  You then use the plunge router and plunge a small hole in the middle of the part you're cutting out.  Then switch to a pattern cutting bit and just guide the router along the pattern on the bottom. 

For the semi-circle, just cut out a full circle on a pattern board, then cut the circle in half and put a straight edge along one side and repeat again with the pattern cutting bit.

[shmokes]

I make it over and over again in 1/4" hardboard (Masonite), sometimes starting in cardboard, with a jigsaw and sandpaper.  When I finally have one I'm happy with I transfer it to the wood with my router and a pattern bit.     Not efficient, but it makes up for my deficiencies.   

[Blanka]

Is wood (or woodlike stuff) good for a bezel Uberhaupt? It is mostly too thick, edges are not fine and finish is not nice. Why not use plastic or stickers on plexi/glass and have it water-cut or plotter-cut?