Begin by cutting two pieces of base molding about 4 in. long with an angle of 22-1/2° (one-half of 45°) on each end, as shown in the drawing. Then, holding piece A flat against the wall and piece B against the round corner, move both pieces until a tight corner fit is formed.Click to see full answer. In this way, how do you do crown molding on rounded corners? How to Install Crown Molding on Rounded Corners Cut a length of crown molding at a 22 1/2-inch angle. Cut two small pieces of molding, both about 4-inches wide, with 22 1/2-inch angles. Place a bead of caulking along the edges of both pieces and insert them up against each other. Additionally, how do you install baseboards on bullnose corners? 3/4” Bullnose Corner Gauge STEP 1: PREP YOUR BASEBOARD PIECES. Photo: Prepping to mark baseboard with 3/4” Bullnose Corner Gauge. STEP 2: MAKE YOUR MARKS (MEASURE YOUR BASEBOARD) STEP 3: MAKE YOUR CUTS. STEP 4: CUT YOUR CENTER PIECE. STEP 5: FITTING. STEP 6: PRE-ASSEMBLE. STEP 7: INSTALL. Just so, what angle do I cut trim for rounded corners? Cut the ends of two pieces of baseboard at an angle of 22 1/2 degrees with a miter saw. Temporarily nail the two pieces to the wall on each side of the corner so that the angles begin at the edges of the bullnose beading and slope away from the corner.How do you cut baseboard outside corners? Mark pieces in place. Some carpenters intentionally cut outside corners long so that they can mark them in place, without having to use a tape measure. Reverse the molding so the long point of the miter is touching the inside corner, and then track a line along the outside of the previous piece of baseboard. 4.