Most woodworking projects
require at least some assembly.
This is especially true for projects
such as tables, cabinets or bookcases where wide panels must
first be built up from several
Traditionally, woodworkers have
used dowels for these assemblies.
As you might expect, dowels add
strength to certain types of joints,
but they serve an equally important function by keeping the
pieces properly aligned during
assembly and gluing. The major
Figure 23-1. The biscuit joiner is powered by the Mark V’s powerplant and
drawback with doweling, howcna be used with either the Model 500 or Model 510.
ever, is that each hole must be
perfectly positioned or the individual pieces simply won't go together. Even a slight error can cause a lot
of pounding and frustration.
During the 1950's a new assembly system called biscuit joinery was developed in Europe. This system
uses flat wooden wafers or biscuits which are glued into semi-elliptical slots on each side of the joint. Due
to the shape of the biscuits, the exact location of the slot is much less critical than a dowel hole. Minor
adjustments can even be made during assembly, so projects go together much more quickly and yet there
is no sacrifice in strength or overall performance. That's why biscuit joinery is rapidly becoming the
preferred assembly system for professional furniture and cabinet makers worldwide.
In addition to its advantages for panel assembly, biscuit joinery can often be used to replace more complicated and time consuming techniques including spline, tongue-and-groove, mortise-and-tenon and dado
BISCUIT JOINER- SETUP AND FEATURES
The biscuit joiner housing attaches to the quill and the blade arbor attaches to the main power spindle of
the Mark V's powerplant (Figure 23-1). It may be used with either the Mark V Model 500 or Model 510.
Follow the setup instructions in the Owners Manual that came with your biscuit joiner.
Some of the important features (Figure 23-2) and capacities of your biscuit joiner are:
• Spring-loaded workpiece guide and safety guard help improve operator confidence and safety.
• Engraved centerline on guide permits easy alignment of workpiece.
• Adjustable depth stops and guide rod grooves permit easy use of three different biscuit sizes (#0,
#10 and #20) for a variety of applications.
• Adjustable pins in guide penetrate stock to provide more positive control and reduce kickbacks.
• Carbide-tipped blade will provide years of normal service without sharpening.
• Builtin dust chute
for easy attachment
of standard 2-1/2"
dust collection hoses.
Figure 23-2. Familarize yourself with these important features of the Shopsmith
BISCUIT SIZES AND CONSTRUCTION
Shopsmith biscuits are produced from select grades of beech.
For maximum strength, the grain is oriented at a 45° angle to the
long axis of the biscuit. During production, biscuits are exposed
to many tons of pressure which compresses the fibers and produces a waffle-like surface for better glue absorption and adhesion.
When glue is applied to the biscuits, the moisture in the glue
causes the biscuits to expand by about 15% of their original
thickness and the joint becomes tight. Since this expansion
occurs very quickly, glue should never be applied to the biscuits
until you are ready for final assembly. Biscuits should also be
protected against water or extremely high humidity. A coffee can
with a tight fitting lid makes a good storage container.
Biscuits are available in three different sizes to meet a variety of
applications (Figure 23-3). All bis-cuits are 5/32" thick.
Figure 23-3. The three available
biscuits are shown here.
#0 biscuits are 1-3/4" x 5/8". They are best for joining smaller workpieces and for edge-to-edge assemblies where high stress is not anticipated. They are also useful for joining narrow pieces such as cabinet
#l0biscuits are 2-1/8" x 3/4". They are recommended for general purpose joinery on all types of projects.
#20 biscuits are 2-3/8" x 1". They are recommended for use on larger projects or joints—such as a table
skirt and leg—which will be subject to high stress or twisting forces. They also provide greater penetration and a larger gluing surface, so they are well suited for plywood or particle board applications.
BISCUIT JOINER SAFETY
Read, understand and follow all safety and operating instructions in the Owners Manuals that came with
the Biscuit Joiner and with the MARK V on which it is mounted.
• Wear safety goggles, safety glasses with side shields or a full face shield.
• Tuck long hair under a hat or tie it up. Do not wear ties, gloves, jewelry or loose clothing.
Roll sleeves up above your elbows. Wear nonslip footwear.
• Before mounting the biscuit joiner on the Shopsmith MARK V, turn on the MARK V and
set the speed dial to SLOW. Then turn off and unplug the machine before proceeding.
• When mounting the biscuit joiner on the MARK V, be certain all locking screws are tightened securely before turning on the machine.
• Be sure the blade is mounted in the biscuit joiner with the teeth pointing in the direction of
the arrows on top the housing. Installing the blade backwards will result in kickbacks and
• Connect a dust collection system to the biscuit joiner dust chute or wear a dust mask.
• Do not allow anyone to stand directly in front of the opening of the dust chute.
• Move the workpiece slowly into the blade—never force it. Feeding stock too rapidly could
• Do not stand directly in-line with the workpiece being fed. In the event of a kickback, you
will be hit.
• Do not rest fingers in the miter gauge slots where they could be trapped and pinched by
kicked back stock.
• Always use the push block in your right hand to feed stock into the blade. This is especially
important when working with small stock.
• Use your miter gauge and/or rip fence as a stop when working with stock less than 6" long
• Always be certain the pins protrude from the guide before beginning operations. Failure to
do this could result in the workpiece being grabbed and thrown by the rotating blade.
• Listen for chatter and signs of looseness at startup. If you hear, see or suspect problems,
turn off the power and unplug the machine immediately. Cor-rect any problems before
• Never use the biscuit joiner for jobs it is not intended to perform such as sawing, grooving,
• Never exceed speed setting "T" on the MARK V's speed dial for biscuit joiner operations.
• Never attempt to use the biscuit joiner on stock less than 3/8" thick.
• Never operate the biscuit joiner without the housing and guard in position.
• Always keep the blade clean and sharp.
• Use only Shopsmith blades and parts for your biscuit joiner. Using non-Shopsmith blades
or parts will create a hazardous condition and will void your warranty.
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 (Fig-ure 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.
Figure 23-4. Mark centerlines on
both pieces of stock to assure proper
Figure 23-5. Here you see typical centerline markings for various
types of joints.
Basic Adjustments and CutsAfter 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 depthof-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. 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
Figure 23-6. Attach the biscuit
joiner to the quill and tighten the
housing collar capscrew. Don’t
forget to tighten the setscrew
which holds the blade arbor to the
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
Figure 23-7. Adjust the depthof-cut setscrews to match the
biscuit size being used.
Figure 23-11. On stock more
than 1” thick, two biscuits may
be used for added strength.
Figure 23-8. Adjust and lock pins
to engage work during cuts.
Figure 23-9. Use the quill adjustment to position blade for cut. Allow
clearance between biscuit joiner and
than 3" and be sure to allow
clearance be-tween the biscuit
joiner arbor and the worktable in
order to prevent damage to the
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
Figure 23-10. Align biscuit centerline with joiner guide and
joiner guide. With a push block in
use a push block in your right hand when feeding stock.
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 facedown 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 TFrame, 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.
Figure 23-12. When joining stock
of different thicknesses a shim may
be used to eliminate adjustments
and assure accurate alignment.
Figure 23-13. If the stock does not
engage both pins, use your miter
gauge to maintain control of the
Figure 23-14. Use your miter gauge
to hold and advance the stock on
mitered cuts. Do not slide the stock
across the miter gauge face.
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
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
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 450 (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
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.
Figure 23-15. When working with large stock, mount the biscuit joiner
diagonally for maximum support of the workpiece.
Edge Cuts in Wide Stock- Working with large or wide stock is
similar to other edge joining oper-ations, 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.
Figure 23-16. For surface cuts,
adjust the table so it is flush with
the biscuit joiner guide when fully
If additional support is needed, use the extension table system (Model
510), a roller stand or a helper to gain control.
Surface Cuts-Surface cuts are necessary for two basic types of joinery: edge-to-face joints, such as along the corner of a cabinet, and Tshelf joints, such as where a shelf joins the sides of a bookcase. Surface
cuts require special setups and additional care.
For edge-to-face joints, mount the biscuit joiner with the Mark V in the
vertical position. Also lock the worktable vertically with the table edge
slightly below the biscuit joiner. With the Mark V unplugged, depress
the biscuit joiner guide to the desired depth stop and adjust the worktable until its surface is even with face of the guide (Figure 23-16).
Finally, mount the rip fence on the table so that it supports the
workpiece at the correct height for the biscuit position.
Figure 23-17. This setup is
ideal for surface cuts along the
edge of the workpiece.
To make the cuts, tip the top edge of the work slightly away from the table and slide it along the rip fence
until one of your centerlines marked on the top edge of the stock is aligned with the engraved centerline
on the joiner guide. With a push block in your right hand, tilt the stock slowly back against the worktable.
As you do the stock will engage the pins and compress the guide to make the cut (Figure 23-17). Pivot
the stock toward you and away from the table before attempting to advance to the next cut.
Figure 23-19. The rip fence and miter gauge can be used as
guides when cutting “blind” biscuits.
Figure 23-18. For surface cuts,
adjust the table so it is flush with
the biscuit joiner guide when
A T-shelf or similar joint is more difficult because one side of the cut must be made "blind." The accuracy
of the joint depends totally on the accuracy of your measurements and setup.
Mount the biscuit joiner with the Mark V in the horizontal position and slide the worktable close to the
biscuit joiner. With the Mark V unplugged, depress the joiner guide to the desired depth stop, set the
stops, and adjust the Mark V table to match this height (Figure 23-18).
A typical setup is shown in Fig-ure 23-19. In this example, the rip fence on an extension table determines
the position of the cut along the length of the stock and the miter gauge locked in its slot determines the
position across the width.
After all measurements have been made and checked, hold one end of the stock elevated and place it
against the rip fence and miter gauge. With a push block in your right hand, lower the stock slowly until it
engages the pins, depresses the guide and finishes the cut. Lift the stock completely before attempting to
move to the next cut.