A dovetail jig or joint fixture is designed to allow the woodworker to create consistent dovetails in a piece of wood. This provides the ability to create two matching pieces of wood that dovetail together to create a woodworking piece. Commonly used to create boxes or wood frames the dovetails provide added strength beyond that of wood glue or screws and nails. The Central Machinery Dovetail Joint Fixture is made in China and sold in the United States through Harbor Freight.
Mounting the Dovetail Joint Fixture
Find an installation location. The dovetail joint fixture must mount to a flat, level and stable workbench.
Drill the mounting holes. Mark and drill four 3/16 inch holes in the workbench using the mounting holes located at each end of the fixture as a template.
Mount the fixture. Use the screwdriver to mount the fixture to the workbench using the drilled holes and the wood screws.
Using the Dovetail Joint Fixture
Place the wood stock. Loosen the four bolts on the front face of the fixture to allow the horizontal and vertical stop pins to move. Spread the stop pins wider than the two pieces of wood stock.
Pull up the Eccentric Rods. Loosen the front and rear fixing screws to pull the Eccentric Rods to the vertical position.
Insert the horizontal wood stock. Place a piece of wood stock into the fixture horizontally from the rear between the bracket and comb table. Tighten rear fixing screws and pull the rear Eccentric Rod down to clamp the wood into place.
Insert the vertical wood stock. Place a second piece of wood stock into the fixture from below, off set from the horizontal piece by the width of one comb. The top edges of the two pieces should be flush.
Adjust the comb table. Loosen the comb table fixing screws and move the comb backwards or forward until the tips of the combs are 5/32 inch clear of the vertical piece of wood stock and re-tighten the fixing screws.
Adjust the stop pins. Move the stop pins until they touch the two pieces of wood stock and tighten their bolts.
Clamp the vertical piece. Tighten the two front fixing screws and pull down the Eccentric Rod to clamp the wood stock into place.
Routing the Wood Stock
Prepare the router. The Central Machinery Dovetail Joint Fixture is designed for routers with a 1/4 inch shank and 1/2 inch, 14 degree dovetail bits only. Install a router guide collar or router ball bearing guide to prevent the bit from coming into contact with the comb.
Cut the dovetails. Turn on the router and guide it in an out between the combs. Make sure to cut each piece of wood to it's full depth but take care not to cut into the comb table or workbench.
Remove the wood stock. Turn off the router and remove the wood stock from the fixture. Test the two pieces together for a tight fit.