Butt Joints Miters and Backsaws

So much for parallel, edge-to-edge joints—now we're going perpendicular. In the joiner's alphabet, we're done with pushing one I against another I; now we're making Ls and Ts.

Pushing one timber against another and nailing them together is fastenery, not joinery. But if you cut a shoulder, a rabbet, on the end of one piece and drop the other into it, and then nail it, that's something else. The rabbet secures the wood in one direction and allows the nails to come in from two directions.

A shoulder will let you cross-nail your butted, end-to-end joints.
Miter joints allow the molding contours to turn a corner.

The miter joints of picture frames and such can also be cross-nailed. Additionally, miter joints in picture frames possess a great aesthetic virtue—the cross section of one piece flows perfectly into the cross section of the other. A molding, no matter how complex, can turn the angle intact and "seem one intire Piece."

Miter joints, like coopered joints, divide the angle of a turn equally between the two joining surfaces. With western architecture based firmly on 90-degree turns, guides for cutting 45-degree miters abound. A miter square has its blade set to form 45 to one side and 135 degrees to the other. Of course if the stuff is large enough, you can position a framing square at 45 degrees to an edge by positioning it so that it crosses the edge at equal numbers on each arm. On smaller stuff, you can use the same method to adjust a sliding bevel to 45 degrees and use it as the bevel square. On the end of a board, a common marking gauge can define a 45-degree angle. Set the gauge to the thickness of the board and use it to run a line parallel to the end grain. Connect the corner on one face and the line on the other and you have 45 degrees.

All of these will give you a guideline for your saw, but a miter box guides the saw itself. The old miter box was hardly a box at all, more like a bench hook with a thick back block with slots to guide the saw. This is now called a miter block to distinguish it from the familiar wooden U-shaped trough of three boards. The front board of the miter box is usually left a bit long to catch on the end of the bench, similarly to a bench hook. This lets you push the work into the far corner of the miter box with one hand and saw with the other.

Miters dwell in the world of appearances, and anything that damages the face side counts against us. Saws leave a rough exit, so you always hold the work in the miter box so that the saw teeth cut into the face, leaving the raggedy edge on the back side. This means you can't reverse a piece in the miter box to cut a reverse angle. Thus, you need a left- and right-hand version of any angle, but many angles means many slots, each one weakening the walls of the miter box. Still, it's easy to make a fresh box or spring for a metal miter box with adjustable tracks for a big backsaw. Metal miter boxes lack a certain aesthetic collectibility, so you might be able to acquire one at a price that is a bargain weighed against its utility.

Metal miter boxes are usually accompanied by their giant backsaws. The back on a saw permits the blade to be made thinner, with finer teeth, leaving a finer kerf than would otherwise be possible. Backsaws are often known by the particular joint they are intended to cut. The smallest and finest are dovetail saws, fine toothed and often with no set at all in the teeth. Next come backsaws in graduated sizes (carcase, sash, and tenon), all of which are used to cut a tenon's shoulders and cheeks. Finally, there are long backsaws intended for use with miter boxes.

The narrow, even, straight cut of the backsaw allows you to cut a miter so true it can't be improved by planing. Much, then, depends on the accuracy of the guide. If, however, you could cut both pieces at the same time while they are held at right angles to one another, any angular error with the saw would be self-correcting.

Sawing "into" the finished surface of a molding in the miter box leaves a clean edge.

You can do this in a rough-and-ready way by setting one piece over the other and sawing down through both pieces. The refined version of this is called "kerfing in," a technique that will arise again in mortise and tenon work. In miter work, kerfing in uses a set frame that tightly holds the two pieces at right angles and guides your saw at 45 degrees, right into the miter. You cut both pieces at the same time, not superimposed, but butted with the best miter you can muster. As the blade re-cuts the miter, one side of the kerf cuts one board and the other side of the kerf cuts the other. Tapped together, the two faces close the gap of the saw kerf, making a perfect miter.

Was this article helpful?

0 0
Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

Get My Free Ebook

Post a comment