In Series 2 of "the Router Workshop" Bob and Rick constructed a cookie box with perfect box joints made with the spacer fence and then added the dovetail liner joint for added detail.
The Liner Kit
The dovetail liner kit consists of two pieces, the set-up block and the off-set block.
The set-up block has a 3/4" dovetail slot and a 3/8" wide slot. It is used to check the dovetail bit height and distance from the 3/8" rail on the spacer fence.
The off-set block also has a 3/8" wide slot and a particial dovetail cut along one edge.
This liner kit must be used with a 3/8" spacer fence, a 1/2" 14 degree dovetail bit and a 3/4" 14 degree dovetail bit (not included).
Cutting The Dovetails
Chuck up a 3/4" 14 degree dovetail bit and mount the spacer fence. If you are using the Oak Park router table and spacer fence the mounting holes are predrilled on both. You will use mounting holes 2 and 4 on both the spacer fence and table. Set the depth of cut at 1/4". Use the set-up block to check the bit height and spacing as shown.
Mark an X on the edges of your material that will be against the 3/8" rail on the spacer fence.
If you experience chipping or breakout, sandwich your material between two pieces of scrap wood and clamp together.
Cut the dovetails across the end of your material. Use a backer block to keep the material verticle as you cut.
The space between the dovetails MUST be 1/2" to fit the 1/2" dovetail slots cut in the liner material.
When cutting the second piece, clamp the off-set block over the rail on the spacer fence. Make sure the DOVETAIL side of the block is towards the cutter. Make the first cut.
Remove the off-set block and continue cutting the dovetails to the end of the material.
The Liner Set Up
The liner material MUST be 3/8" thick. We suggest you use wider material than necessary for the finished product and trim it later.
Chuck up a 1/2" 14 degree dovetail bit in a table mounted router. You will use mounting holes 1 and 3 on the spacer fence and 1 and 5 on the router table.
Set the depth of cut at 1/4". Use the set-up block to check the bit height and spacing as shown. The 1/2" dovetail bit is flush with the left hand side of the 3/4" dovetail slot in the set-up block.
Cutting The Liner - First Side
The dovetail slots are cut WITH the grain of the wood. Exert downward pressure with a push block when making the cuts. Cut dovetails all the way across your material.
When you get to the end, turn the stock around and cut the angled dovetail on the other edge. Be sure to hold the material firm when making this cut as the bit is pulling the material away from you. This will result in a particial dovetail cut along the straight edge as shown.
Now is a good time to check the fit. The space between the dovetails MUST be 3/4" to fit the dovetail cuts on the outside pieces.
Cutting The Liner - Second Side
Clamp the off-set block over the rail on the spacer fence. Be sure the SQUARE edge is facing the bit as shown.
Flip the liner material over so the dovetail slots face upwards.
Make a short test cut and check the 1/8" spacing around the dovetail shape. Tap the fence left or right if necessary and run another sample (in the same location). When satisfied complete the first cut.
Remove the off-set block and continue to cut the dovetail slots across your material.
Dry fit the liner. Cut the liner to suit the thickness of the stock you are using. Glue all three pieces together and sand smooth. Joint and/or cut the edges to the desired width for your project.