The cam fitting is a discreet knock-down joint for carcases constructed from man-made boards. It is used to make corner joints, or for holding shelves and vertical dividers. A round-head metal dowel screwed into the vertical component or side panel locates with a cam-action boss set in the underside of the horizontal component or shelf. Turning the boss with a screwdriver pulls the joint tight. The standard straight dowel is made with a coarse thread that screws directly into the board. Another
type of dowel screws into a plastic or metal insert. Double-ended dowels secure straight end-to-end joints, and a cranked version is used for mitres.
1 Fitting the dowels
For a corner joint, set a marking gauge to half the thickness of the board and scribe a line on the inside of the side panel. Mark off two centres equidistant from each edge; a wide panel may require another dowel in the middle. Drill pilot holes for coarse-threaded dowels, and screw them in place.
2 Inserting cam-action bosses
Scribe a line centrally on the end of the shelf and, using the side panel as a guide, mark out the positions of clearance holes for the dowels. Drill the holes to the required depth. On the underside, use a Forstner bit to drill stopped holes that intercept the centre of the dowel holes, and insert the bosses.
3 Assembling the joint
Each boss is marked with an arrow that should point towards the side panel. Assemble the joint with a dowel in each hole, then turn the bosses with a screwdriver to lock the components together.
Chapter 2 4 Although woodworking machinery produces work with ease and accuracy, handtools are still important in joint-making. It is often more convenient to hand-make a limited number of joints, and it is impossible to make certain joints with a power tool. This glossary lists joint-making hand-tools, power tools and machinery; special jigs and templates are found with the relevant joints.
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