Traditional joinery
In these times of modern welding equipment it is not uncommon for much decorative ironwork to simply be welded together. However, prior to the advent of modern welding equipment in the late 19th century, blacksmiths used a variety of other methods to join pieces of metal together, such as forge welding, collaring, and mortise and tenon joints.
The current railing that Red Star is working on is employing mortise and tenon joints to secure the railing pickets and the ornamentation. In a mortise and tenon joint, a hole is either drilled or punched through a piece of steel (this is the mortise) and another piece of metal is passed through the hole (this is the tenon). In our current project, the railing pickets had tenons formed on both ends. These tenons were passed through holes drilled through the horizontal rails and the ornamentation and then punched down to create rivets that hold everything together.
In these photos you can see our shop foreman Jake forging the tenons on the ends of the railing pickets. In the first photo you can see him forming the tenons on the ends of the pickets using a spring dye and our power hammer. The dye molds the ends of the 5/8” hot picket into a thin tenon about 1/4” wide. In the second photograph the tenon is clearly visible on the end of the picket.
In this photo you can see part of the railing that has already been put together. In the middle of the ornamentation you can see the end of a tenon that has been heated up and ready to be hammered into a rivet.
The tenons are heated with a torch until they are glowing red.
Here you see a rivet being formed. A shaping tool is placed over the hot tenon and then hit using a sledgehammer. The force of the hammer on the shaping tool reforms the hot tenon from its pin shape to a small cone-shaped rivet.
In this final photo you can see the finished rivet. The rivet holds the horizontal rail and ornament in place between itself and the upright picket.