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A simple V-cradle jig lets you hold a mitered frame or box part at a consistent angle while cutting a spline slot on a tablesaw. For greater support, build a fence-straddling version that clamps the workpiece. Choose the jig for the piece you are cutting, set the slot from the actual workpiece—not a generic offset—and verify the setup on scrap before cutting project stock.
Choose a jig for the workpiece
| Jig | Best suited to | How it guides and holds the work |
|---|---|---|
| Simple V-cradle | A loose mitered frame or box part | A V-shaped face supports the corner as you carry the jig across the blade. |
| Fence-straddling jig | A loose workpiece that needs more support and clamping | End panels fit over the rip fence; angled fences support the work and a hold-down block clamps it. |
| Cradle for an assembled box | Cutting key-spline slots into an already assembled box or frame | A dedicated cradle rides in the saw’s table slots and holds the assembly at 45 degrees. This is a different jig, not a variation of the fence-guided V-cradle. |
| Commercial tenoning jig | A shop that already has a compatible jig and needs a rigid work holder | Check its fit on your saw and capacity for the specific workpiece; compatibility is not universal. |
Build the simple V-cradle
WOOD magazine’s example uses a found 2×4 as a base and a small piece of 1/4-inch hardboard as the V-faced support. The V is made with two opposing 45-degree cuts.
- Prepare a stable base and attach the hardboard so its face can support the corner of the workpiece. The source’s example uses a 2×4 base; size the base to your work and saw setup.
- Set the tablesaw blade to 45 degrees. With the hardboard against the miter gauge, make one angled cut into its front edge.
- Flip the hardboard and make the opposing cut. Together, the cuts form a V that seats the mitered corner.
- Position the jig and workpiece on scrap to determine where the blade will cross the work. Check the alignment against the actual piece and intended spline location before cutting project stock.
For the example using 3/4-inch material, WOOD’s Jim Heavey places the blade kerf 3/8 inch from the edge of the hardboard cut line. That offset is specific to the example’s geometry, not a universal setting: the V shape, workpiece thickness, and blade position all affect the result.
Optional angled presentation
WOOD also demonstrates tilting the blade 15 degrees for a diamond-like spline presentation. This is an optional variation, not part of the basic V-cradle procedure. It changes the setup, so use stable support and test the cut on scrap before using it on the workpiece.
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- This spline jig strengthen your miter joints and add a design element in the form of splines across the miters.
- Works with both table saw and router table, cut a variety of spline slots or dovetail Keyways, suitable for making picture frames small boxes and other joinery.
- Perfect for projects as narrow as 0.6 inch and up to 20 inch wide; Can clamping 5-42mm(0.2-1.7 Inch) thick frame.
- Benefit from the unique structure, there are no metal obstacles above the saw blade and router bit, can effectively avoid accidental damage; Besides, the workpiece almost close to the table top, ground clearance only 1MM.
- TOOLCOOL spline Jig is made of aluminum alloy, CNC-machined, anodized finished, robust construction, reliable and has a long service life; Come with a allen wrench and hex bit, you can operate it manually or use a hand drill.
Build a more supportive fence-straddling jig
For a setup that supports and clamps the piece more firmly, Woodcraft describes a jig made from hardwood plywood or MDF. Its end panels straddle the rip fence and should fit without side-to-side play. Two hardwood fences are set at 45 degrees and parallel to each other across the face panels.
- Make flat face panels and end panels that straddle your rip fence. Fit the jig so it slides as intended without wobbling side to side.
- Attach two hardwood fences at 45 degrees to the face panels, keeping them parallel.
- Add a sacrificial backer to the right-hand fence to help reduce exit tear-out.
- Make a hold-down block that clamps over the workpiece. Arrange it to keep the piece against both the jig and the saw table, without interfering with the blade path.
Cut corresponding slots at both ends
- Mark the show face and lay out the slot on the workpiece.
- Place the work on the right-hand fence with the show face outward. Shift the rip fence to align the marked slot with the blade.
- Clamp the hold-down over the piece, keeping the slot exit area supported where practical.
- After the first cut, reverse the jig orientation for the corresponding cut at the opposite end. Use the other fence, keep the show face outward, and position the hold-down to cover the slot exit area.
Woodcraft’s separate tenoning-jig guide describes a related fence-straddling shop-made jig with flat face panels, a square fence block, careful rip-fence fit, and a sacrificial fence; it identifies spline slots as one possible operation. A tenoning jig can be an alternative, but check its fit and capacity against your saw and workpiece.
Rank #2
- Versatile Joinery Jig: Create decorative and joint-reinforcing splines for boxes, frames, cabinets, picture frames, and woodworking projects; works as a spline jig for table saw and router table applications with precise alignment control.
- Adjustable 45 Degree Sled: Durable jig base securely holds workpieces at a 45 degree angle while guiding smoothly past router bits or saw blades; ideal for spline joinery, box joint jig setups, finger joint cuts, and decorative corner details.
- Multiple Cutting Styles: Supports straight, angled, dovetail, V-groove, and custom spline patterns using router bits or table saw blades; expands woodworking versatility for furniture making, boxes, cabinetry, and trim projects.
- Precision & Stability: Aluminum miter bar with adjustable tension blocks delivers smooth no-slop movement in standard miter slots; zero-clearance inserts help reduce tear-out while adjustable fences improve positioning accuracy and repeatability.
- What’s Included: Rockler Deluxe Spline Jig For Table Saw; (1) Miter Bar with Adjustable Tension Blocks; (1) Miter Jig Base; (2) Adjustable Fences; (5) MDF Zero-Clearance Inserts; (1) Miter Stop with Easy-to-Grip Five-Star Knob; Hardware Pack.
Set the slot for the joint and spline
Slot dimensions depend on the joint, stock, and spline material. For the miter-slot operation it describes, Woodcraft gives typical guidance of a 3/8–1/2-inch slot depth, about 1/8 inch width with a standard blade, and a slot roughly 1/8 inch from the inside miter corner. It also describes 1/4-inch-wide slots for large case pieces, made with a dado set or multiple passes with a standard blade. Treat these as application-specific starting points; confirm the fit and location on scrap.
- Set depth: Choose a slot depth appropriate to the joint and spline, and confirm blade height on scrap. For a standard tablesaw spline-slotting operation, the cited 3/8–1/2-inch depth is guidance, not a requirement for every project.
- Set width: Match the slot to the spline stock. Woodcraft describes about 1/8 inch for a standard blade and 1/4 inch for larger case pieces; wider slots may require a dado set or multiple standard-blade cuts.
- Fit the spline: Aim for a snug fit. For its illustrated key-spline method, Woodcraft recommends ripping stock slightly wider than the slot depth, planing it to thickness, then fitting it so it seats snugly with light pressure.
- Control tear-out: Keep the work down and against the fence or jig, and use a sacrificial backer at the blade exit.
For a completed box, use a dedicated cradle
A completed box or frame needs a different setup from a loose mitered part. Woodcraft’s approach uses a plywood cradle that rides in the saw’s table slots and holds the assembly at 45 degrees. The described cradle includes a wooden blade guard and a travel stop to prevent overtravel, plus a sacrificial panel to reduce tear-out.
Rank #3
- 【Aluminum Alloy Right Angle Spline Fixture】The right-angle spline jig is made of aluminum alloy, NC processing, anodized, with a solid structure, reliable, durable and wear-resistant, not easy to deform or break, and long service life.
- 【Spline Jig Suitable for】Clamping range: frame thickness 5-42mm/0.2-1.65inch, safety recommendation: frame depth 15-500mm/0.59-19.7inch. Adaptive clamping range, can be applied to more projects.
- 【Practical Design】The spline clamp can fix the frame left and right, which is more stable, providing a safer way of operation, away from danger. Ultra-low ground clearance, the workpiece is almost close to the table, high accuracy.
- 【Adjustable Corner Dovetail Jig for Table Saw Router Table】The spline clamp is more convenient to add design to your frame, can be used with table saws and planers to cut various spline grooves or dovetail keyways. Great for making picture frames, small boxes and other joinery.
- 【Package Content】You will receive 1pair aluminum alloy right angle spline jig, 1pcs hex wrench and 1pcs hex bit. Each spline jig is about 180x50x100mm/7.09x1.97x3.94inch(LxWxH), practical set for woodworking.
Design the cradle and stop for the specific assembly and saw. Set the blade height so the slot does not cut through to the box interior, and verify the cut and travel limits on a safe test setup before cutting the finished assembly.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Check the setup and manage tablesaw hazards
OSHA identifies kickback risks when stock twists or binds against the blade or is caught by its teeth. Blade condition, incorrect blade height, and poor-quality stock can contribute. A homemade jig does not replace the saw’s required guards or other safeguards; follow the saw manufacturer’s instructions and OSHA guidance.
Rank #4
- PRECISION BUILT - The Woodpeckers Spline Jig has 2 sections of aluminum Super Track, secured by UHMW glide strip lined, powder-coated steel legs. Also inlcuded are 4 molded flip stops to keep your splines aligned.
- STENGTHEN YOUR MITER JOINTS - You can make a joint rock solid and add a design element at the same time by adding spline across the miters with the Spline Jig.
- VERSATILE PROJECT CAPACITY - The Woodpeckers Spline Jig can handle narrow projects from 1/2" to 16" wide on the wider setting. When projects exceed 16", just move the tracks inward to tackle long projects up to 3 feet wide.
- TABLE SAW & ROUTER TABLE JIG - For narrow splines, this jig works great on the table saw. For wider splines or dovetail work, the jig works great with the router table too.
- MADE IN USA - Like all Woodpeckers products, the Spline Jig is precisely machined and carefully inspected in our Strongsville, Ohio, facility just south of Cleveland.
- Inspect the saw, blade, fence, and safeguards before use; do not work with cracked or knotty stock.
- Check that the jig sits square, does not rock or bind, and is appropriate for the saw and operation.
- Secure and support the workpiece so it stays against both the jig and table throughout the cut.
- Verify blade height, slot position, and spline fit on scrap before cutting the project piece.
- Plan how the jig and offcut will clear the blade, and avoid deep cuts.
- Where possible, stand to the side after feeding stock to reduce exposure to kickback and flying splinters.
OSHA advises using suitable jigs when guards cannot be used; that does not mean a jig authorizes removing a guard. Use a setup that preserves the saw’s required safeguards, and do not proceed if the operation cannot be performed safely under the manufacturer’s instructions.
Quick Recap
Best Value
- Material: Made of CNC aluminum alloy, strong and durable. Anodized to protect against rust.
- Clamping Range: Safety recommended frame depth 0.6 - 20 inches; can clamp frames 5-42mm (0.2-1.7 inches) thick.
- PERFECT JOINT: Strengthen your miter joints with this spline clamp, this clamp can be used for both dovetail and spline clamps.
- Widely Applicable: Suitable for table saw and router table, cutting various spline grooves or dovetail keyways for making picture frames, small boxes and other joinery.
- Safe and Precise: There are no metal obstacles above the saw blade and router bit, which can effectively avoid accidental damage. Only 1mm above the ground, ensuring precise application.
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