Perfect Miter Joints Every Time
The trick is to assemble door and window trim with biscuits first, then nail it in place.
Synopsis: An experienced builder shares his time-tested process for installing miter joints — a process which saves time, requires less skill, and yields better results. In the authors case, it also put an end to his habit of falling off of mud-buckets used as improvised step ladders. This article highlights a logical and methodical approach for cutting miter joints and casing.
Ten years ago, my approach to installing casing was fairly traditional: Measure, cut, test the fit, walk back to the saw, trim the cut. Then one day, I climbed onto a joint-compound bucket to test the top piece of trim on a doorway a few feet upstream of a short flight of stairs. Microseconds later, I felt my feet describing an arc about my head and proceeded down the stairs like an otter wearing tennis shoes. It’s amazing how such a short trip can get so rocky, so quickly; it made me realize my methods (and stepladder) needed an upgrade.
A few months later, I happened to work with James Chambers, a talented trim and cabinet builder from Old Saybrook, Conn. He cut, biscuited, and clamped his casings together on the floor, then installed them as a complete unit. His miter joints were perfect, and the installation nearly flawless. By the next job, I had abandoned the mud-bucket shuffle and converted to the preassembly method of casing, which has improved work quality, reduced both the level of skill and hours required for the job, and extended the useful lifetime of my lower back. Here’s some of what I’ve learned over the years, wrestling with and pinning miles of casing.
Get set up, then cut the miters
When the material arrives, my crew and I orient it in the cutting room so that a 16-footer does not have…