How to Build a Table Saw Tenoning Jig for Casework

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A tenoning jig turns a table saw into a controlled shoulder-and-cheek cutting machine. For casework, it is useful for making stub tenons, haunched tenons, and loose-looking but accurately fitted frame joints in cabinet doors, face frames, and carcase parts. A good jig is safer and more repeatable than balancing a workpiece against the miter gauge, but it must be built square and adjusted without forcing the saw to do work it cannot handle.

What the Jig Does

The jig holds the workpiece vertically or horizontally and guides it past the blade. The most versatile version rides in the table saw’s miter slot while a tall fence supports the stock. A clamp keeps the work from tipping or shifting as the blade cuts the tenon cheeks and shoulders.

For most casework, build a jig that carries stock up to about 4 inches wide and 1-1/2 inches thick. Larger work can be handled, but the taller the workpiece, the more leverage it puts on the jig and the more important a second clamp becomes. A tenoning jig is not a replacement for a commercial sliding table when you are cutting large doors, long beams, or repeated production parts.

Materials and Hardware

Use 3/4-inch Baltic birch plywood for the base and fence. Cabinet-grade plywood is preferable to construction plywood because it stays flatter and has more consistent layers. Hardwood works for runners and cleats, but plywood runners are easier to replace if they wear.

You will need a flat base approximately 12 by 18 inches, a vertical fence around 8 inches high and 16 inches long, one or two 3/8-inch or 1/4-inch hold-down clamps, and hardware to attach the fence. A pair of tenoning jig clamps is convenient, though inexpensive toggle clamps work if their mounting locations do not interfere with the workpiece.

For a one-off cabinet project, shop-made plywood and a simple clamp are usually enough. If you will cut dozens of identical tenons, a commercial table saw tenoning jig can save setup time and usually offers better fine adjustment.

Build the Base and Runner

Cut the base square, then cut a runner to fit the miter slot with almost no side-to-side play. The runner should sit slightly below the table surface—about 1/32 inch is enough—so the base slides on the saw table rather than dragging on the runner.

Attach the runner with the jig upside down on the saw. Place coins or thin washers in the slot to raise the runner, apply glue, and lower the base onto it. Add screws from the top, keeping every screw head below the surface. Do not rely on glue alone. Let the glue cure before trimming the runner ends.

Slide the base through the slot and check for binding. If it rocks, the runner may be too narrow, the slot may contain debris, or the base may not be flat. Fix this now; a small error at the runner becomes a noticeable angle at the tenon.

Install and Square the Fence

Set the fence on the base so its face is roughly 90 degrees to the table. Use a reliable square against both the saw table and fence, then attach it with bolts through oversized holes. The slots let you make small corrections later.

Do not assume the fence is square because the plywood edge looks straight. Check at both ends and again after tightening the hardware. A fence that leans only 1/32 inch over 8 inches can produce a tenon that fits at one end and binds at the other.

Add a replaceable sacrificial face to the fence. It should extend slightly below the bottom of the workpiece and be thick enough to support the stock without flexing. Mark the blade path only after the jig is adjusted. Keep all clamp hardware at least 1 inch away from the blade’s maximum cut line.

Set Up and Cut the Tenon

Install a sharp combination blade or a dedicated table saw tenon blade. A flat-top grind leaves cleaner shoulders, but a standard combination blade works for most casework if you clean the shoulder afterward with a chisel. Never use a dado stack in a jig unless the saw, arbor, guard system, and jig are specifically suitable for it.

Mark the tenon on scrap from the same stock. Set the blade height for the cheek cut, then make a test cut and measure the remaining tenon thickness. For a 3/4-inch board, a tenon 1/4 to 3/8 inch thick is a practical starting point. Aim for a cheek depth of 1/2 to 2/3 of the stock thickness, leaving enough shoulder to resist splitting.

Clamp the workpiece firmly against the fence, with the reference face in the same orientation for every part. Make the first cheek cut, flip or reposition the workpiece as required, and sneak up on the final thickness with small adjustments. Remove no more than about 1/32 inch per test adjustment. For shoulders, use a stop block or marked registration point so every tenon lands at the same location.

Common Failures and Safety

A loose runner causes tapered or inconsistent tenons. A fence that is not square creates angled cheeks. Excessive clamp pressure can bow thin stock, while too little pressure lets the work climb or shift. If the blade burns, stalls, or leaves a rough surface, check blade sharpness, alignment, and cut depth before increasing feed pressure.

Use the saw’s riving knife when the cut allows it, keep hands behind the fence, and use a push handle to move the jig. Disconnect power before changing the blade or adjusting hardware. The jig must never contact the blade, and the workpiece must be fully supported before the cut begins.

Before cutting good parts, make at least two test tenons. Test the joint with the actual mating piece: a useful fit is firm by hand but does not require hammering. Once the jig is tuned, record the blade height, fence position, and shoulder setting on the jig so the next casework project starts with a known setup.