Biscuit Joiner

Owned by Michael Giannattasio
Last updated: Feb 01, 2021 by Andrew Molloy
8 min read

A biscuit joiner (or sometimes plate joiner) is a woodworking tool used to join two pieces of wood together. A biscuit joiner uses a small circular saw blade to cut a crescent-shaped hole (called the mouth or “slot”) in the opposite edges of two pieces of wood or wood composite panels. An oval-shaped, highly dried and compressed wooden biscuit (usually made of beech or particle wood.) is covered with glue, or glue is applied in the slot. The biscuit is immediately placed in the slot, and the two boards are clamped together. The wet glue expands the biscuit, further improving the bond.

Safety

  • Use personal protective equipment. Always use certified safety glasses. Other protective equipment such as dust mask, non-skid closed shoes, or hearing protection used for appropriate conditions will reduce personal injuries.
  • Dress properly. Do not wear loose clothing or jewelry. Keep your hair, clothing and gloves away from moving parts. Loose clothes, jewelry or long hair can be caught in moving parts.
  • Keep work area clean and well lit. Cluttered areas invite accidents.
  • Keep bystanders away while operating a power tool. Distractions can cause you to lose control.
  • Keep the power cord away from heat, oil, sharp edges or moving parts of the machine. Damaged or entangled cords increase the risk of electric shock.
  • Do not force the power tool. Use the correct power tool for your application. The correct power tool will do the job better and safer at the rate for which it was designed. 
  • Do not use the power tool if the switch does not turn it on and off. Any power tool that cannot be controlled with the switch is dangerous and must be repaired. 
  • Disconnect the plug from the power source before making any adjustments, changing accessories, or storing power tools. Such preventive safety measures reduce the risk of starting the power tool accidentally.

Personal safety

  • Stay alert, watch what you are doing and use common sense when operating any power tool.
  • Do not use any power tool while you are tired or under the influence of drugs, alcohol or medication. A moment of inattention while operating power tools may result in serious personal injury.
  • Do not overreach. Keep proper footing and balance at all times. This enables better control of the power tool in unexpected situations.
  • Hold tool by the insulated gripping surfaces when performing an operation where the cutting tool may contact hidden wiring or its own cord. Contact with a “live” wire will make exposed metal parts of the tool “live” and shock the operator.
  • Always maintain a firm grip on the biscuit joiner handle and motor housing with both hands to prevent loss of control.
  • Keep hands away from cutting area. Keep hands away from blade. Do not reach underneath work while blade is rotating.  
  • Avoid cutting nails and knots. Inspect for and remove all nails from lumber before cutting. Try to layout cuts between knots.
  • Wait for the cutter to stop before setting the tool down. An exposed cutter may engage the surface leading to possible loss of control and serious injury.
  • Use clamps or other practical way to secure and support the work piece to a stable platform. Holding the work by hand or against your body is unstable and may lead to loss of control. Never hold work in your hand, lap, or against other parts of your body.

Selecting the Biscuit

Biscuits are 5 /32" thick. They are available from Porter-Cable in four sizes. Choose the largest biscuit that will accommodate the type of joint being made.

Operation

To Start and Stop Tool

  1. Connect tool to power circuit.

  2. Grip tool firmly to resist starting torque, and squeeze trigger switch (A) Fig. 1, to START tool.

  3. Release trigger switch to STOP tool.
  4. Switch Lock: the trigger switch may be locked in the “ON” position as follows:
    1. Squeeze trigger switch to START motor and depress lock button (B) Fig. 1, while releasing trigger switch. Release lock button.
    2. To STOP tool: squeeze trigger switch and release, while leaving lock button free to spring out.

Adjusting Depth of Groove

A “quick set” depth adjusting turret (A) Fig. 2, provides for quick changes in depth of cut to accommodate the various sizes of available biscuits and other accessories. To set depth of cut: rotate depth-adjusting turret until desired size marking on turret aligns with the index mark (B) Fig. 2. The following depth settings are provided: 0 For “0” size biscuits, 10 For “10” size biscuits, 20 For “20” size biscuits, MAX For “6” size accessories, provides maximum depth of cut with 4" blade.

FF For Porter-Cable “FF” biscuits…which are smaller and require a blade change by a Shop Technician.

Fine Adjustment: (Depth of Groove)

The “quick set” depth adjustment is adjusted at the factory to produce joints with nominal clearance (biscuit to groove). A fine adjustment is provided allowing the operator to reduce or increase the clearance as desired. Adjust as follows:

  1. Use a 7/16" wrench to loosen lock nut (A) Fig. 3.
  2. Rotate fine adjustment knob (B) Fig. 3, to desired position (rotate knob clockwise to reduce depth of cut, rotate knob counterclockwise to increase depth of cut).
  3. While holding adjustment knob in desired position: tighten lock nut firmly.

Adjustable Fence

The Biscuit Joiner in the SOA, is equipped with an integral, adjustable fence which:

  • Provides micro height adjustment, distance scale includes indexes to top of cut, to center of cut, and to bottom of cut.
  • Tilts 0° through 135°, with an adjustable stop at 90°.
  • Does not have to be removed to make “flush” cuts.

Height Adjustment: (see Figs. 4 & 5)

  1. Loosen locking knob (A), and rotate knob (B) to position the fence as desired, (rotate knob clockwise to raise fence, rotate knob counterclockwise to lower fence).
  2. The depth scale (C), indicates the distance from the top edge of the work piece to the blade: NOTE: The bottom line on scale (C) begins at 1 /4" and all lines are in 1 /16" increments. • The line across the center of the index block (D), indicates the distance to the center of the blade. • The top edge of the index block (D), indicates the distance to the bottom of the blade. • The bottom edge of the index block (D), indicates the distance to the top of the blade. • The width of the index block (D), is equal to the thickness of the blade.
  3. Once fence is in desired position, tighten knob (A), to secure in place.

Angle Adjustment: (see Figs. 6, 7, 8 & 9)

  1. Loosen locking knob (A).
  2. For angles between 0° and 90°: swing fence downward until desired angle on lower scale (B), aligns with lower index mark (E). Tighten knob (A), to secure in place.
  3. For angles between 90° and 135°: swing fence downward until the “gate” between the upper scale (D), and lower scale (B), aligns with locking knob. Swing scale arm down to align knob with upper scale. Move fence until desired angle on upper scale (D), aligns with upper index mark (C). Tighten knob (A), to secure in place.

Dust Port

The tool is equipped with a dust port (A) Fig. 17. A large volume of sawdust and chips will be exhausted from this port during tool operation. A dust bag (B) Fig. 18 and a dust/chip deflector nozzle (C) Fig. 17 are furnished. A standard 1" vacuum hose can be connected to the dust port to facilitate dust collection. Do not operate the tool without a dust nozzle and dust bag, or a vacuum hose, attached to the dust port. Dust/Chip Deflector Nozzle The dust/chip deflector nozzle (C) pushes onto the dust port (A) Fig. 17.

Attaching Dust Bag

Depress spring clips (A) Fig. 18, and clip dust bag (B) on end of dust/chip deflector (C). The bag is equipped with a zipper to ease emptying of the collected material.

Vacuum Hose: A standard 1" vacuum hose can be attached to the dust port to provide a means for connecting the tool to your vacuum cleaner or dust collection system.

Positioning Grooves (Slots)

The number of grooves (biscuits) used in a joint may be varied to provide the strength required for the particular application. Typically, the center of the first groove is positioned approximately two inches from the edge of the work with additional grooves spaced at three to six inches on centers. In most cases, one line of grooves (biscuits) positioned approximately along the centerline of the material is used. On thicker material, an additional row(s) of biscuits may be used for added strength. The possibilities are almost endless. Position the two work pieces (to be joined) in the relationship desired after joining. Mark the centerline of each groove required as shown in Fig. 19. Use a square to assure accuracy.

Corner Joints

  1. Layout groove positions as described in POSITIONING GROOVES.
  2. Set depth stop turret to desired biscuit (or other accessory), size.
  3. Set the tilt fence to the 90° position (see ANGLE ADJUSTMENT Section of this manual).
  4. Set fence height adjustment to desired height (usually 1/2 the material thickness), (see HEIGHT ADJUSTMENT Section of this manual).
  5. Clamp the work piece securely.
  6. Position the tool to the work-piece with the bottom of fence resting on the work piece. Align guide notch (A) or (B) Fig. 20, with a groove centerline. Apply pressure to auxiliary handle (C) Fig. 20, to keep front of tool and fence in firm contact with work piece.
  7. Hold tool firmly as shown in Fig. 21, squeeze trigger switch to start tool.
  8. At a slow, steady pace, push tool forward in base as far as depth stop allows.
  9. Release trigger switch to stop tool and remove tool from work.
  10. Repeat steps 6 through 9 until all the grooves for this joint are completed.

NOTE: Assemble all joints and verify alignments before applying glue (see Fig. 22).

Surface (“T”) Joints

  1. Layout groove positions as described in POSITIONING GROOVES.
  2. Set depth stop turret to desired biscuit (or other accessory), size.
  3. Mark centerline of joint on work piece “A” (see Fig. 23).
  4. Clamp a straight edge guide to the work piece, 3 /8" back from the joint centerline (as marked in Step 2). Clamp work piece securely (see Fig. 24).
  5. Set tilt fence to 0° position (see Angle Adjustment Section of this manual).
  6. Position tool to work piece with bottom of base against straight edge and guide notch (C) Fig. 25, aligned with a groove centerline. Apply pressure to handle (D) Fig. 25 to hold tool firmly in place.
  7. Hold tool firmly as shown in Fig. 21. Squeeze trigger switch to start tool.
  8. At a slow, steady pace, push tool forward in base as far as depth stop allows.
  9. Release trigger switch to stop tool and remove tool from work.
  10. Repeat steps 5 through 8 until all the grooves in work piece “A” are completed.
  11. Follow steps 3 through 10 of CORNER JOINTS Section to complete required grooves in work piece “B” Fig. 23.

NOTE: Assemble all joints and verify alignments before applying glue (see Fig. 26).

Butt Joints

Tool adjustment and operation for producing butt joints (see Fig. 19), is the same as for CORNER JOINTS.

Miter Joints

  1. Layout groove positions as described in POSITIONING GROOVES.
  2. Set depth stop turret to desired biscuit size.
  3. Set the tilt fence to desired angle (see Angle Adjustment Section of this manual).
  4. Set fence height adjustment to desired height (see Height Adjustment Section of this manual).
  5. Clamp work piece securely.
  6. Position tool to work piece utilizing either guide notch (A) or (B) Fig. 27, to align tool with a groove centerline. Apply pressure to auxiliary handle (C) Fig. 27, to hold tool firmly in place.
  7. Hold tool firmly as shown in Fig. 28, and squeeze trigger switch to start tool.
  8. At a slow, steady pace, push tool forward in base as far as depth stop allows.
  9. Release trigger switch to stop tool and remove tool from work.
  10. Repeat Steps 5 through 8 until all the grooves for this joint are completed.

NOTE: Assemble all joints and verify alignments before applying glue (see Fig. 29).

Clean-up

When you are finished working with the Biscuit Joiner, clean the area before leaving the workstation. There are 4 Trash barrels in this room, and each one has a broom, bench brush and dust pan attached. You must use these items to clean up your work areas at each machine, when you are finished working there. Also, there are scrap barrels at each workstation to deposit scraps of material, which may be useful for someone else. Please do not put materials with stray hardware or glue on them, or food/drink items, only re-usable materials.