Tip #23
Successful Routing (continued)
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version of Tip - Pg. 1-3, Pg. 4-6, Pg. 7-9

Dovetails

Figure 10-10. These are typical examples of dovetail joints

A dovetail is one of the strongest joints in woodworking because it will resist a pulling strain in every direction but the one from which the tenons are inserted into the slots. Two common applications are shown in Figure 10-10.

The same dovetail cutter is used to form both the tenon and the slot. Mating the parts is a matter of positioning the cuts in proper relationship to each other.

Spacing of the cuts is determined by the size of the cutter and the design of the joint. One method is to mark the workpiece and align each cut with the cutter. Another method is to pencil mark the worktable so that the edge of the workpiece can be moved forward to a new mark after each cut. When you mark the worktable, first determine the centerline of the spindle; then mark the cutlines by measuring toward the worktable edges, front and rear. One technique is to use measuring tape which has a gummed side. This may be placed on the worktable and then removed when not in use.

Figure 10-11. Dovetail tenons can be formed as shown. The table height lever (Model 500) or table height crank (Model 510) is used as the forward feed mechanism.

To cut dovetail tenons as shown in Figure 10-11, position the worktable parallel to the way tubes. Use the table height lever (Model 500) or table height crank (Model 510) as a forward feed mechanism, the stop collars from the lathe tailstock to control table movement, the quill feed lever to obtain exact depth of cut, the rip fence as a platform for the workpiece and the miter gauge to square the work-piece to the cutter. When feeding the workpiece forward against the cutter, move the worktable slowly, and be sure the workpiece is clamped securely in place. After the cut is made, turn off the Mark V and return the worktable to the starting position. If desired, place the workpiece for the next cut and repeat the procedure.

Figure 10-12. Make dovetail slots using a feather board and push block.

The mating cuts are formed with the worktable in the horizontal position and with the fence used as a guide (Figure 10-12). The table is brought up as close to the cutter as possible, and the final adjustment is made by extending the quill. The workpiece is fed forward against the cutter. A stop is clamped on the fence to control the length of cut. For spacing, the fence can be moved for each new cut or the worktable can be advanced-again by using the table height mechanism as a forward feed device. When feeding the workpiece against the cutter, hold it firmly on the worktable and push it slowly. Caution: If the cut is for a through dovetail, use a scrap block between the work and the table.

Figure 10-13. This long dovetail slot might be required for a sliding assembly. Note the position of the worktable and the rip fence and the use of the feather board and fence extension.

The tenon on a single, wide dovetail is formed by making two cuts, one on each end of the stock. The mating part is formed the same way, with the waste stock cut away by running the work across the cutter within limits set by the two end cuts and stop blocks. Care must be exercised in positioning the pieces for successive cuts, but testing in scrap wood before cutting will make this easier. By using the setups shown in Figures 10-13 and 10-14, you can join boards edge-to-edge or provide a sliding arrangement.

Figure 10-14. A dovetail tenon is formed in two passes, one one each face of the stock.

Cut the slot in one pass by placing the table as shown and adjusting it so the cut is made directly down the centerline of the board (Figure 10-13). Depth of cut is set by lowering the quill and locking it in position. Feed the workpiece slowly and keep it flat against the table. Don't force the workpiece. The tenon requires two passes. The workpiece is positioned so the cutter forms the tenon on one side of the board. Then the workpiece is turned and the second pass is made; thus, the cutter completes the forming of the tenon on the opposite surface of the board (Figure 10-14). Here, even more than elsewhere, be sure the workpiece is held firmly and flat against the table.

Figure 10-15. A sliding table greatly simplifies cutting a dovetail slot in an extra wide piece.

Wide stock that must be grooved across the grain requires a sliding table arrangement to which the work can be clamped (Figure 10-15). The fixture is constructed as shown in Figure 10-16, with the runners situated so the platform will slide smoothly on the table. The table is raised to an approximate position and the final adjustment for depth of cut is made by using the quill feed lever.

Figure 10-16. Construction details of the sliding table. Runners should fit snugly against the edges of the table (Model 500) or the table tubes (Model 510). Click on image for larger view.

Figure 10-17. Two passes are needed on an extra-wide workpiece. Be sure to align the bit and the kerf.

With this arrangement the length of cut is limited to the distance from the cutter to the tubes. On narrow stock the groove can be completed in one pass by using a spacer board between the workpiece and the fence. Wide boards require two cuts from opposite sides of the board on a common centerline. Alignment is important. Locate the cutter center by marking a pencil line on the fence of the sliding table. Mark lines on the workpiece to locate the centerlines of the grooves. Align these with the mark on the fence. Since the first half-cut (on wide boards) removes the line, it is necessary to use a straightedge to realign the workpiece with the mark on the fence before completing the cut (Figure 10-17). This method is not limited to dovetail grooves; straight grooves are cut with router bits, and the procedure is exactly the same.

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