Uses For a Jointer Jig
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 because of the speed at which it is grown and the methods used for milling, it often warps, cups, twists, or bows as it acclimates to the local climate. We have all had the experience of searching through piles of lumber looking for straight pieces, only to find that the lumber continues to warp and bow after we get it home.
Many woodworking projects depend on perfectly straight lumber. When you have boards that need a little straightening, the preferred tool is a jointer, sometimes called a jointer/planer. You can always use your table saw to square up the board once you have one flat, true surface, but you need the jointer to create that one surface.
Jointer Machine vs. Jointer Jig
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.
The good news is that there's a simple jig for your table saw that can do a great deal of the work of a jointer. In this project, you'll learn how to 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.
The essence of this jig is a plywood base fitted with a guide strip that slides along the miter gauge slot on your table saw. On top of the jig, you'll attach an adjustable 1 x 6 that holds a pair of clamps, which will secure the stock you want to square up on your table saw. There is no finishing required for this project, and you should need no more than 1 to 2 hours to complete it.
Tools and Materials
- Table saw
- Drill with twist bits
- Fixed-base router with a router table
- 1/2-inch straight-cutting router bit
- 1 x 6 SPF lumber, 3 feet long (1)
- 3/4-inch-thick sanded (AC) plywood (12 x 24 inches)
- Tape measure
- 1/2-inch chisel
- Open-end wrenches (2)
- Quick-release toggle clamps (2)
- 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
Cutting the Guide Slots
To begin building your table saw jointer jig, you'll need a piece of 3/4-inch plywood measuring 12 inches wide by 48 inches in length, and a 1 x 6, cut to 36 inches in length. You'll also need a 60-inch long strip of stock ripped to dimensions of about 3/4 x 3/8 inch, but you can use pretty much any straight piece of scrap stock for this piece.
- 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 inch from the edge of the board.
- Set your router table's fence 1 inch away from the edge of the bit.
- Next, make a pencil mark on the fence, 3/4 inch in each direction from the edges of the board. These marks will denote the start and stop points of the slot.
- Start up the router and ease the board down onto the bit, with the leading edge of the board at the far pencil mark. Then, guide the board along the fence until the trailing edge of the board has met the trailing pencil mark.
- 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.
- 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.
Safety tip: Be very 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.
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.
- 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.
Recess the Bolt Head
Now, you will 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.
- Using your pencil, 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.
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.
Attach the Clamps
The next step is to attach the quick-release toggle clamps to the upper portion of the jig.
- 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.
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. 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
With a scrap piece of stock placed below the pads, adjust the clamp pads accordingly, using a pair of open-end wrenches.
Cut the Guide Strip
The table saw jointer jig is nearly complete. The next step is to 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. You'll want to 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.
Attach the Guide Strip
The last assembly step is to attach the guide strip to the base of the jig.
- 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 some 1 1/4-inch deck screws. Be sure to drill pilot holes and countersink them to ensure the screw heads do not protrude past the face of the strip.
Trim the Jointer Jig
The last step in building the jig is to trim the edge of the 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 very minimal side-to-side play. If you experience any side-to-side play, you may wish to 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.
Using the Jointer Jig
- To use the jig, position the board you wish to square up into the jig, clamping it in place so that 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.
- 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. 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. You now have one perfectly straight edge.
- 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.
Note: Keep in mind that this jig is suited for cutting boards no more than 4 feet in length. For longer boards, you may wish to make a jig with a longer base that can hold longer boards.