Super-Simple Way to Cope Shoe Molding

You can't cut perfect miters with a dull blade, one with too few teeth or one that's designed for ripping. Check your blade for sharpness by cutting a 45-degree miter on a 1x3 or larger piece of oak or other hardwood. If you don't know how to cut a 45 degree angle, just look at the angle measurements on the base of the miter saw. If the blade cuts smoothly with very little pressure and leaves a clean, almost shiny cut with no burn marks, it's sharp enough to cut good miters. When you check your blade or shop for a new one, look for one labeled as a “trim” or “fine crosscutting” blade. A 10-in. blade should have at least 40 teeth, a 12-in. blade at least 60. If the blade is for a sliding miter saw, be sure the teeth have a hook angle of zero to negative five degrees. Teeth with a neutral or negative hook angle are less aggressive and safer for sliding miter saws. Expect to spend at least $50 for a carbide-tipped blade that'll perform well and last.

Even on perfectly square corners, 45-degree angles won't always yield perfect miters. Wall corners can be built up with corner bead and compound, and window and door frames can slightly protrude or be recessed behind surrounding drywall. That's when you have to start fiddling with the angles to get a tight fit. In most cases, you'll be making adjustments as small as a quarter of a degree. If the gap is small (about 1/16 in.), recut one side of the miter. If the gap is larger, you'll have to recut both boards or the trim profiles won't line up.

Here's a trick to make miters look great, but it only works if you're installing raw trim that will get finished after installation. Apply a thin layer of wood glue to the end grain of each piece before you assemble them. Use a damp (not wet) cloth to remove excess glue from the joint. Sand over the miter with a small piece of 120-grit sandpaper. Sand across the joint and finish up by carefully sanding out any cross-grain sanding marks by moving the paper with the grain from both directions.The sawdust from sanding will mix with the glue to fill any small gaps. Sanding the miter will also even out any slight level differences and make the job look more professional.

Whether you're edge-banding a tabletop as we're showing here, trimming out a window or door, or learning how to measure baseboards for a miter cut and installing baseboard, it's always best to fit one miter at a time whenever possible. Start with a scrap of molding with a miter cut on it as a test piece. When you have the first miter fitting perfectly, mark the next one. Then cut and fit the adjoining miter before you nail either piece. For edge banding, work your way around the project using the same process for each edge piece.

There are all kinds of ways to find odd angles and for cutting angles in wood, but most carpenters simply make a guess and then cut a pair of test pieces to see how lucky they are. The angle of these two walls looks to be less than 45 degrees. A good guess would be about 30 degrees. Divide 30 by two to arrive at the miter angle, and cut a couple of scraps at 15 degrees. Here there's a gap in front, so we need to increase the angle slightly and recut the scraps at 16 degrees. When you've zeroed in on the correct angle, the scraps will fit perfectly, and you can then cut the actual moldings.

Cut a back bevel on miter joints that are open in front but touching at the back  (acompound miter cut). To create a back-beveled cut on a standard miter saw, place a pencil under the molding. If you have a compound miter cut box, tilt the blade a degree or two to cut the back bevel.

In a perfect world, you could nail the trim flat to the wall and the miter would look great. But in reality, minor variations in level between the jamb and the wall often interfere. To solve this cutting angles in wood problem, start by pinning the inside edge of the trim, making sure the miter joint is pressed tight together. Then, while the miter is still tight, drive a pair of brads through the outside corners at opposite angles to pin it.