13 Simple Steps To Making A Router Table Spline Jig

Top Tip!

In use, pass the work in the spline jig once only from right to left. A repeat cut may not follow exactly the same path, resulting in a wider slot.

Step 1

Prepare the base of the spline jig. It is important to remember that the edge that bears against the router fence should be planed straight.

Step 2

Measure half way on the straight edge and mark line across the middle. Black biro is used here for clarity.

Step 3

Mark a 45° mitre on each hardwood fence.

Step 4

Cut off the waste, and sand the mitred end on the disc sander.

Step 5

Mark off a line each side at 45° and 10mm away from the centre line.

Step 6

On each line, mark the positions of three screw holes and drill with a 4mm drill.

Step 7

Countersink the reverse side.

Top Tip!

Ensure that the countersinks are sufficiently deep so that the screw heads won’t foul the surface of the router table.

Step 8

From the point where the centre line meets the edge, mark off another pair of lines at 45°, thus forming a broad ‘arrow’. These lines locate the sides of each fence on the base board.

Step 9

Place each fence in turn along a line, leaving the mitred face around 10mm from the edge of the router table spline jig. Mark off and cut to length; use the disc sander to clean up the end.

Step 10

At this point, clamp one fence in position, ensuring that it’s at 45° to the front edge. Insert one screw and adjust the fence position if required.

Step 11

When the fence is in the correct position, secure it with another G clamp and drive in the remainder of the screws.

Step 12

Position the second fence and clamp to the base board, ensuring that the internal angle is 90°. Drive in the three screws.

Step 13

Completed router table spline jig and in use and on the router table.

Finished jig
Jig against the router fence

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