Suggestions...

[nickds1]

I have some 90 degree trim for a room I'm panelling.

Part of the ceiling is slightly sloping off the horizontal by 18 degrees so the angle is not 90 but 108.

The question is how to alter the 90 degree trim to 108, i.e. by taking 9 degrees off each face...

But how to do that on a 2.4 MTR bit of trim?

Thoughts...

 

[Droogs]

either draw the angle on the end and mark along the length where the edges are and plane it with a hand plane or with a tablesaw using featherboards to keep the part in place ie not bending or lifting, as you push it through with pushrods