I am not at home so I cannot scan in the 2 different ways that come to mind. I don't think a butt method would look good though. If you join them back together with a 45 will you have enough room though? Not sure in what way you mean you have 3 inches to play with.
That will be difficult to get layed out precisely but one method would be to cut the bench on a 45 to begin with do not simply cut it in havlf and then cut your miters - although theoretically you could do it since we are talking an inside corner.
The way I might do it would be to position the half that has already been cut on a 45, directly over the half that needs to be cut, like on a pair of sawhorses, turn the lights out in your shop and position a small wattage flourescent light exactly over the edge where it will cast a full length shadow exactly where your cutline needs to be. You can then draw a line on the shadow line.
I have never actually done this so i don't know that it will actually work but I don't see why it wouldn't.
Use plumb lines to ensure the pewhalf is exactly over the top of the one needing cut.
I think I would also have enough confidence to simply draw the 45 lines with a large square. i have a foldout 4' tile square I use for stuff like that it is super handy.
Also, since that pew probably has a slant to it (?) you are going to have to do some hand work (chisel and plane - could use a belt sander though) after you cut it because the joint will not close until you remove the wood below the joint surface. A circular saw will not cut that bevel properly because the seat slant will change in degree as you travel transversley across the seat portion.
Use duct tape on the bottom of your saw plate to prevent scratches on the pew.
Please let us know how you end up doing it; you will probably discover a better way altogether and I would like to know what it is because I may very well do this as well one day. Post pictures when you are done!
Last edited by TexasTimbers; 04-10-2007 at 03:52 PM.