Tip #12
Biscuit Joiner
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version of Tip - Pg 1-4, Pg 5-8

Basic Biscuit Joinery Techniques

Marking Joints- The only marking normally required for biscuit joinery is to indicate the centerline for each biscuit's location. These markings are usually made on the back side of the stock and may be made with a square (Figure 23-4) or freehand. Marked centerlines are then aligned with the engraved centerline on the biscuit joiner guide while quill and worktable adjustments are then used to control the biscuit's vertical position. Figure 23-5 shows typical markings for various types of joints.

Basic Adjustments and Cuts- After mounting the biscuit joiner on the Mark V (Figure 23-6) and establishing a basic setup as shown in the biscuit joiner Owners Manual, several adjustments must be made before using the accessory. These basic procedures apply to all types of joints, so review these steps before each biscuit joiner operation.

Begin by selecting the size biscuit you will be using and set the depth-of-cut accordingly. This is done by unplugging the Mark V and compressing the spring-loaded guide until the desired grooves on the guide rods are even with the biscuit joiner housing. The three grooves in the guide rods indicate the correct settings for #0, #10 and #20 biscuits respectively.

Figure 23-7. Adjust the depth-of-cut setscrews to match the biscuit size being used.

Adjust both depth stop setscrews (Figure 23-7), so that the guide cannot retract beyond the desired depth.

Next adjust the two pins in the guide face and lock them firmly in place (Figure 23-8). These pins provide important kickback protection and should penetrate about 1/32" in hard woods and 1/16" into softer woods.

Figure 23-8. Adjust and lock pins to engage work during cuts.

When using the Mark V Model 510, position the worktable so the face of the biscuit joiner guide is above the table insert (Figure 23-6). This will keep the leading edge of the stock from interfering with the ribs in the worktable surface.

Finally, adjust the height of the biscuit joiner. Press the stock against the joiner fence until the blade is visible and adjust the quill until the blade is at the desired height (Figure 23-9). Normally the biscuit location will be about midway between the top and bottom, but higher or lower positions may occasionally be desirable.

The most important factor is that the cuts be at the same height on both pieces of stock. When making these adjustments, the quill should not be extended more than 3" and be sure to allow clearance between the biscuit joiner arbor and the worktable in order to prevent damage to the table surface. After all adjustments have been made, turn on the Mark V and set the correct speed. Guide the workpiece with your left hand until the biscuit centerline mark on the stock is aligned with the engraved centerline on the biscuit joiner guide. With a push block in your

right hand (Figure 23-10), press the stock slowly against the guide, compressing the springs until the guide reaches the depth stops... then retract the stock. Repeat this procedure for each cut on both pieces of stock before changing the setup or height adjustment.

Panel Construction- Panel construction or edge-to-edge joinery is one of the most common woodworking operations. For best results, place the boards face down next to each other and mark biscuit centerlines on the back side. Then cut the biscuit slots and assemble the boards in this face-down position to help assure a flat, smooth final surface.

Typically, allow one biscuit for each foot of length in an edge-to-edge joint, with a minimum of three biscuits. Space the biscuits evenly and position the end biscuits at least 3" from the ends of the boards so the boards will engage both of the pins in the guide when the biscuit slots are cut.

End Grain and High Stress Joints- Because of the wood's high porosity, end grain joints--such as T-Frame, L-Frame or End Butt--are almost impossible to make with glue alone. Using biscuits will strengthen these joints because the biscuits are glued face-grain-to-face-grain.

For best results, use the largest biscuit available that will allow at least 1/4" of stock at each end of the biscuit slots. On wide joints, such as a T-shelf, use multiple biscuits, allowing as little as 1/2" between biscuit slots.

On stock over 1" thick--especially on high stress joints such as a table leg and skirt--two or more rows of biscuits may be used for added strength (Figure 23-11).

When joining stock of different thicknesses-such as a 1" thick skirt being joined to a 2" square table leg-a thin piece of scrap wood or hardboard can be used as a shim (Figure 23-12) to eliminate the need to make quill adjustments for each thickness. This assures that the setback will be exactly the same on all joints and that the biscuit slots will be aligned correctly for easy assembly.

Short and Narrow Stock- Workpieces less than 6" in width or length must be handled with special care because the pins in the joiner guide will not engage the stock and a kickback or injury is possible. For these cuts, align the centerlines and lock the miter gauge into the worktable to serve as a guide and stop. Hold the workpiece against the miter gauge face and advance it slowly and firmly into the biscuit joiner (Figure 23-13).

If you are making multiple matching components--such as door frames or rails and stiles for a cabinet front--you can make the setup once and cut all biscuit slots quickly and accurately.

Miter Joints- For corner miters, mount the biscuit joiner so that it faces the front of the Mark V with the guide perpendicular to the miter gauge slots (Figure 23-14). Adjust the worktable so one of the miter gauge slots is under the biscuit joiner and the quill is extended 3" to avoid interference between the safety grip and the Mark V's powerplant. Set your miter gauge to 45° (or to match the angle of the miter), place your workpiece against the miter gauge with the centerlines aligned, and adjust the safety grip to hold the stock securely.

Make the cuts by advancing the miter gauge and stock into the cut together. Do not slide the stock across the miter gauge and into the biscuit joiner as this will not produce an accurate cut. A piece of coarse sandpaper may also be attached to the surface of the biscuit joiner guide to keep the stock from creeping during the cut.

Edge Cuts in Wide Stock- Working with large or wide stock is similar to other edge joining operations, but additional support must be used to give the operator control of the stock for accuracy and safety. This is achieved by mounting the biscuit joiner diagonally, at about a 30° to 50° angle to the miter gauge slots (Figure 23-15). With the Model 510, check your setup to be sure the table height crank doesn't interfere with the stock.

If additional support is needed, use the extension table system

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