In Part 1 of this article, we reviewed the details of casing joinery and how to measure for new casing around a door frame. We also reviewed the necessary cut list, so that you can cut your casing right the first time. In Part 2, we moved on to the details of baseboard. We covered the best methods for installing casing and the use of hand-driven nails in Part 3. We’ll finish Chapter 2 by exploring methods for pre-assembly.
Chapter 2: Part 4
A serial publication of excerpts from Trim Made Simple by Gary Katz
Training techniques for apprentice carpenters and serious DIYers
New adhesives, spring clamps, and fastening systems have made it easier than ever to pre-assemble casing. For casing wider than 3 in., pre-assembly and miter reinforcement—with biscuits, splines, or pocket screws—is the best way to ensure long-lasting miters. To improve craftsmanship—and make the job easier and more enjoyable, use some of the same techniques to guarantee tight-fitting miters around your doors.
|1. Clamp the head to each jig. Use A-clamps to secure an assembly jig to each end of the head casing. Make sure the casing is tight against the stops.|
|2. Glue the miters. Spread a thin layer of carpenter’s glue on each miter.|
|3. Clamp the legs to the jigs. Rest the head casing and assembly jigs on the edge of a sawhorse or on your miter saw stand. Tilt the head casing and each leg into position, squeezing the miters tightly closed. Use A-clamps to secure the legs.|
4. Spring clamp the miters. Glue joints won’t be strong unless they dry under pressure, and putting glue under pressure helps it ‘set’ faster. Use the wrench to spread each spring clamp as wide as possible. Position the clamps on top of each miter (see below).
|5. Carry the frame to the wall. Strong A-clamps make it possible to move the casing off your work area and store it temporarily against a wall while the glue ‘sets’. Wait ten or fifteen minutes before installing the frame.|
Making pre-assembly jigs
On some jobs, I don’t have room—or enough time, to set up a full-size worktable. These simple homemade jigs make it easy to pre-assemble casing without a worktable, using only a miter saw stand or a sawhorse. You should have at least four of these jigs, so several sets of casing can be assembled at one time.
1. Square of 1/2-in. or 3/8-in. plywood. Cut the plywood to about 8 in. square.
2. 1/4-in. strips on two corners. If you don’t have a table saw, a length of 1/2 in. doorstop will provide all the strips you need. Glue the strips, clamp them to the jig, and then tack them in place with brads or pins.
3. Non-slip material. Cut pieces from a router mat (www.rockler.com: $8.79) and fasten them on the back of each jig. Use fast acting glue, like 2P-10 (we’ll cover this in a future article) or contact cement to secure the non-slip material to the jig.
Stay tuned for the next chapter from Trim Made Simple: Casing Windows!