How do I make an octagon out of crown molding

are you wanting this to be flat or project out
if you are looking for it to be flat you don’t need both angles – flat leave the blade 90 degrees to the horizontal and cut the mitre at 22.5

-- Jeff - Bell Buckle, TN

projected out like in the picture of the clock. So if the clock face was sitting on a table, the inside opening would be raised. Does the molding upper edge need to sit up against the wall, or sit flat on the saw?

If you want it to be beveled, here is the formula you need.

Someone also posted a link to a program to do the calculation for you, but I don’t have that handy at the moment.

-- Greg D. -- the price of freedom is tolerance

Have a look at this project. The sides of those trays are beveled and require compound cuts. Comment #8 has a link to a program that does the calculation.

If the final assembly is flat – the backs of all the sides are in the same plane – then do what j_olsen said.

-- Greg D. -- the price of freedom is tolerance

OK may be a dumb question, but do I position the crown molding so the upper edge is up against the wall of the saw, then cut?

that will depend on how much projection you want
if you want the full projection of the crown follow what brantly said

-- Jeff - Bell Buckle, TN

oops

-- ♫♪♪♫♫ Saddletramp, saddletramp, I'm as free as the breeze and I ride where I please, saddletramp ♪♪♪♫♪ ...... Bob W....NW Michigan (Traverse City area)

I will give these suggestions a try.

Thanks for all your help.

I will post on whatever the outcome is:)

Thanks again.

if its just a flat octagon frame
the cutting angle is 45 degree

Dennis