compound miter angles??

[Reed Gray]

Any crown molding finish carpenters out there to help me with this one?

http://www.youtube.com/watch?v=8oVw70_jAQY

I am turning some of these. To simplify cutting off the corners so I can mount it between centers, I decided to take it to the table saw, 45 degree angle on the blade, 45 degrees on the miter gage. Well, the angle wasn't right, so after turning one of the between center points down square I took it back to the saw and adjusted the blade and miter gage to fit the cut. Turned out to be about 47 degrees on the miter guage, and 36 on the blade angle. Any one know the exact angles?

Doing it on the table saw is much simpler than his very precise measuring and hand sawing, and easier than my quick eyeball laying out of lines, then using a 1 1/2 inch wide chisel to lop off the corners. Also better than turning the corners down on the lathe, which moves the finished points up higher, making the piece more of a deep vessel.

robo hippy

[Bruce Pratt]

Reed,

Miter gauge should be 45. If I got my geometry right, the angle on the blade is 90-arccos(sqrt(3)/3) = 35.3; so your 36 is pretty close.

Bruce

[Kyle Iwamoto]

Your miter saw does not have those marks? My saw has a detent and a tick mark for cutting CM flat on the saw. A quick Google search says 52/38.

[Reed Gray]

Thanks. I never considered my miter saw. It does have the marks, but I don't know how to use them. Concrete man, not finish carpenter, and I lost the book. I don't know if I could do it on my miter saw or not, it is almost 20 years old, and they are a lot better now. I did check the miter gage with a big speed square, and the 45 degree mark is right on, so, not sure why it ended up being at 47 degrees, but it does mount properly now.

Thanks again for the help.

robo hippy