Tip #29
Doing Jointery on Your Table Saw
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Pg. 1-3, Pg 4-6, Pg 7-9, Pg 10-12, Pg 13-15,
Pg 16-18, Pg 19-21, Pg 22-24, Pg 25-27, Pg 28, Table 3-1

Other Dado Accessory Joinery

Figure 3-32. Some of the joints you can form by working with a dado accessory: (A) rabbet, (B) dado, (C) end flap, (D) middle lap, (E) lapped miter, (F) notched, and (G) combination dado and rabbet (good for box corners). Click on image for larger view.

All of the joints that are shown in Figure 3-32 can be cut by using a dado accessory. A problem with the simple dado joint is that it leaves a visible joint that is not attractive (Figure 3-33). The lines are hidden when the project is designed with facing strips or a front frame (Figure 3-34). To create a more acceptable appearance when the joint can't be hidden, you can install shelves that are wider than the sides of the case. As shown in Figure 3-35, the front edges of the shelves can be treated in various ways to contribute to visual appeal.

Figure 3-33. A disadvantage of the dado joint is that its joint line is visible.

Figure 3-34. The joint lines are hidden if the project calls for facing strips or a front frame.

Figure 3-35. The joint lines will not be so noticeable if you design shelves like this. Click on image for larger view.

Figure 3-36. A stopped dado results when you do not cut entirely across the stock. A stop block can be used to control the length of cut. Click on image for larger view.

A very professional way to conceal dado joint lines is to work with stopped dadoes. This simply means that the dado cut is not continued completely across the stock. To control the length of the cut, you work with a stop block secured to the rip fence (Figure 3-36). This, of course, leaves an arc where the cut stops. The shelf, or whatever insert, can be shaped in one of the ways shown in Figure 3-37 to accommodate the arc. Another method is to use a small chisel to cut away the arc material so shelves can be inserted as shown in Figure 3-38.

Figure 3-37. Shelves can be shaped this way to conform to the arc that is part of a stopped dado.

Figure 3-38. The arc area of the stopped dado can be cleared out with a chisel; the shelves can then be fitted this way.

Rabbet Cuts-A rabbet is an L-shaped cut made on the end of stock or along the edge. The width of the cut may be gauged with the miter gauge stop rod or by using a spacer on the rip fence. Warning: Never position the miter gauge stop rod so it crosses in front of the dado accessory.

When rabbet cuts are needed along the length of stock (this may be called for when the back of a bookcase or other project is recessed into the frame), the rabbet is cut with the stock sliding against the rip fence.

The size of the rabbet is deter-mined by the piece that will be joined to it. For example, if you were recessing a 1/4" panel into the back of a bookcase frame made of 3/4" stock, the rabbet would have to be 1/4" deep (to accommodate the panel) by about 3/8" wide (to provide fastening area without loss of strength to the side).

While rabbets can be cut with a conventional saw blade as described later in this chapter, they are more easily formed with a dado accessory. To obtain the most accurate results, make a fence facing like the one shown in Figure 3-39. To form the relief arc that is needed in the facing, continue in this manner: Raise the table above the dado accessory and bolt the facing to the rip fence. Lock the fence so the dado accessory will cut about three-quarters of the facing's thickness; then very slowly lower the table until the arc's height is about 3/8" deep.

Figure 3-40. Use a fenc efacing when cutting edge rabbets. It's much better to work this way than to move the workpiece between the fence and the dado accessory.

To form an edge rabbet, lock the rip fence so the distance from the fence facing to the outside of the dado accessory equals the width of the rabbet. Adjust the blade projection for the depth of the rabbet. Hold the workpiece snugly against the facing and make the pass as shown in Figure 3-40.

Figure 3-41. A spacer on the rip fence can be used to gauge the cut width of an end rabbet. Position the spacer so it is well in front of the dado accessory.

End rabbets may be cut in similar fashion but a spacer is mounted on the rip fence and the miter gauge with safety grip advances the work (Figure 3-41). The rip fence is locked so the distance from the spacer to the outside of the dado accessory equals the width of the rabbet; the blade's projection is set for the rabbet's depth. Figure 3-38. The arc area of the stopped dado can be cleared out with a chisel; the shelves can then be fitted this way.

Figure 3-42.Cutting a groove for a tongue and groove joint. Be sure the stock has ample bearing surface against the insert.

Tongue-and-Groove Work-To perform tongue-and-groove work, assemble the dado accessory so you'll get the groove width you need. Set the projection for the depth of the groove; then make the pass as shown in Figure 3-42. Be sure that the stock has ample bearing surface against the insert. To ensure that the groove will be exactly centered, assemble the dado accessory parts to make the cut narrower than you need. Make one pass and then turn the stock end-for-end and make a second pass.

Figure 3-43. A tongue is formed by making matching rabbet cuts on opposite edges of the stock. Always cut the grooves first and then form the tongues to fit.

The tongue is formed by making two opposing rabbet cuts on the stock's edge (Figure 3-43). Make a first cut with one side of the stock against the fence and make a second cut after turning the stock end-for-end. It's easier to make adjustments for the rabbet cuts that form the tongue, so always shape the grooves first and fit the tongue to the groove.

Figure 3-44. A tenon is formed by making two rabbet cuts. The spacer controls the total cut width. Clean out waste by making repeat passes.

Forming a Tenon-A tenon can be formed by making two matching rabbet cuts, controlled by the setup shown in Figure 3-44. The distance from the spacer to the outside of the dado accessory equals the length of the tenon. The blade's projection equals one-half of the stock's thickness minus half the thickness of the tenon. Make repeat passes to clean away the waste stock; then turn the work over and repeat the procedure (Figure 3-45).

Figure 3-45. To finish the tenon, turn the stock over and repeat the procedure.

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