Building a Jointer Jig for Your Table Saw

Wood stock, particularly the stuff that passes for dimensional lumber at modern big-box home centers, isn't the most agreeable of products. It often reaches the shelves before it is fully dried and warps, cups, twists, or bows as it acclimates to the local climate. However, woodworking projects depend on perfectly straight lumber, so hen you have boards that need a little straightening, the preferred tool is a jointer, sometimes called a jointer/planer.

The problem is that jointers are rather pricey and bulky—not exactly suited to a small shop or working on location. Quite simply, there are more versatile tools that are your first priority when putting together a woodworking shop. Build a simple table saw jointer jig that will give you the clean, straight edges necessary to do glue-ups and make other tight-fitting joints.

What You'll Need

Equipment / Tools

  • Table saw
  • Drill with twist bits
  • Fixed-base router with a router table
  • 1/2 inch straight-cutting router bit
  • Tape measure
  • 1/2 inch chisel
  • Pencil
  • 2 open-end wrench
  • 2 quick-release toggle clamps

Materials

  • 1 1 x 6 SPF lumber, 3 feet long
  • 3/4-inch-thicken sanded (AC) plywood (12x24 inches)
  • 1/2 x 2-inch hex bolts with flat washers, lock washers, and wing nuts (2 each)
  • 1 1/4 inch deck screws
  • 3/4 inch wood screws
  • 60-inch-long strip of stock ripped to dimensions of about 3/4 x 3/8 inch

Instructions

  1. Set up the Router

    Set up your fixed-base router with a 1/2-inch straight-cutting bit and mount it on your router table. Adjust the height of the bit to about 1/8-inch above the table surface. You'll be making two slots in the 1 x 6, each about 1 inch in from the ends of the board, perpendicular to the board's long axis. Each slot will stop 3/4 of an inch from the edge of the board. Set your router table's fence 1 inch away from the edge of the bit.

  2. Mark the Board

    Next, make a pencil mark on the fence 3/4 of an inch in each direction from the edges of the board. These marks will denote the start and stop points of the slot.

  3. Start the Router

    Start the router and ease the board down onto the bit, with the leading edge of the board at the far pencil mark. Guide the board along the fence until the trailing edge of the board has met the trailing pencil mark.

  4. Repeat on the Other Side

    Lift the board off the bit, and repeat for the slot on the other side. At this point, you can flip the board over and make the first slot cuts on the opposite side of the board in the same manner.

  5. Repeat the Four Slot Cuts

    Raise the router bit another 1/8-inch and repeat the four slot cuts, using the same procedure. Continue this process until both slots are cut completely through the board.

    Warning

    Be cautious when pushing end grain against your router table's fence, as end grain can bind against the fence and cause kickbacks. Work slowly and methodically and consider dropping your router bit speed down a little bit to prevent burning.

  6. Drill the Bolt Holes

    With the slots cut in the upper board, the next step is to cut a pair of 1/2-inch-diameter holes in the lower plywood. Each of the two hex bolts will go through these holes, then through the slots in the 1 x 6. This will allow the jig to be adjusted for jointing boards of various widths.

  7. Reposition and Mark the Board

    On your shop table, position the upper board on the plywood base, centering it on the long axis (about 6 inches in from each end) and 2 1/2 inches in from the right edge of the plywood base. Using your pencil, make a mark through the left end of the slots onto the plywood below. Remove the upper board, then drill a clean 1/2-inch hole through the plywood at each of the two pencil marks.

  8. Recess the Bolt Head

    Cut recesses in the plywood base so that the heads of the hex bolts can sit below the surface of the plywood. Turn the plywood base of over and insert the two bolts through the newly created 1/2-inch holes. Use your pencil to outline the flat edges of the bolt heads on the plywood. Remove the bolts and use a 1/2-inch bevel-edged chisel to remove enough material to completely recess the bolt heads into the plywood base.

    Marking the Bolt Head Location
    Chris Baylor
  9. Assemble the Jointer Jig

    Now you can assemble the jig, using the plywood base, the slotted 1 x 6, and the bolts, washers, lock washers, and wing nuts. With the two hex bolts recessed into the lower base of the jointer jig, turn the base over and position the slotted 1 x 6 onto the bolts. Complete the assembly by adding a flat washer, then a lock washer and a wing nut to each bolt.

    At this point, verify that the upper 1x 6 slides smoothly against the plywood base and that it can be securely held in any chosen position by tightening the wing nuts.

    Assembling the Jointer Jig
    Chris Baylor
  10. Attach the Clamps

    Position the base of each of the two clamps about a 1/4 inch in from the front edge of the slotted 1 x 6, 2 inches inside the edge of the slots. Attach each of the clamps to the 1 x 6 with four 3/4-inch wood screws.

    Attach the Quick-Release Toggle Clamps
    Chris Baylor
  11. Adjust the Clamps

    With the quick-release toggle clamps attached to the upper portion of the table saw jointer jig, the next step is to adjust the clamps. With a scrap piece of stock placed below the pads, adjust the clamp pads accordingly, using a pair of open-end wrenches.

    Tip

    The pads of the clamps should be adjusted so that they securely hold a piece of 1 x stock (1 x 6, 1 x 8, etc.), but not so tight so that pressure could tear the clamps off the jig.

    Adjusting the Clamps
    Chris Baylor
  12. Cut the Guide Strip

    Rip a 5-foot-long strip of stock on your table saw, which will be attached to the bottom of the base and slide through the miter-gauge slot on the bed of your table saw. Verify the size of the slot on your saw, but typically, the miter slot is about 3/4-inch wide by 3/8-inch (or slightly less) high. The idea is for the strip to glide smoothly through the slot with minimal play.

    Cutting the Miter Strip
    Chris Baylor
  13. Attach the Guide Strip

    As you're facing the table saw, measure from the left side of your saw blade to the right edge of the left miter slot. Add 1/8-inch to this measurement. Turn over the jig and measure in that distance from the right-hand side of the plywood base. Using a straight edge, mark a parallel line at this distance along the right edge of the plywood.

    Position the guide strip wide edge down on the left edge of the line, and attach to the jig with 1 1/4-inch deck screws. Drill pilot holes and countersink them to ensure the screw heads do not protrude past the face of the strip.

    Attach the Miter Strip
    Chris Baylor
  14. Trim the Jointer Jig

    With the table saw blade set below the bed of the saw, position the miter strip into the miter slot and verify that the jig glides smoothly across the entire length of the table with minimal side-to-side play.

    Tip

    If you experience any side-to-side play, go back and make a slightly tighter miter strip.

    Once you're satisfied with the movement of the jig, pull the jig all the way forward (toward your body), raise the saw blade to slightly more than 3/4-inch. Start the saw and trim the right-side edge of the jointer jig. The saw blade should remove only about 1/8-inch of plywood. Your table saw jointer jig is now complete.

    Trim the Jointer Jig
    Chris Baylor
  15. Using the Jointer Jig

    To use the jig, position the board you wish to square up into the jig, clamping it in place so the edge to be trimmed is just hanging over the right side. You may need to adjust the wing nuts to widen or narrow the jig's clamps to accommodate boards of various widths.

  16. Trim the Edge

    With the jig adjusted and the board clamped in the desired position, raise the blade to a height just above the surface of the stock, start the saw and trim the edge of the stock. You now have one perfectly straight edge.

    Warning

    As with any table saw operation, do not stand directly behind the blade, but off to the left side, just in case there is a kickback.

  17. Trim the Opposite Side

    To trim the opposite side of the stock to create a board that is perfectly square, remove the jig and simply use the table saw with the fence to rip the other edge of the board. By running the jointed edge along the fence, you are guaranteed a perfectly square board. 

    Tip

    Keep in mind that this jig is suited for cutting boards up to 4 feet in length. For longer boards, make a jig with a longer base that can hold longer boards.