Shear plates are installed using a specialized dapping tool consisting of a cutter head and pilot bit. The dapping tool cuts grooves in the face of the wood that are concentric to the bolt hole. Two small cap screws on the face of the cutter head can be raised or lowered to adjust the depth of the grooves. For the shear plates to function properly, it is critical that the dapping tool be used when installing shear plates.
This 3:32 video demonstrates the techniques required to properly cut daps in timbers for shear plates to be installed. This video uses a drill press, but a heavy duty 3/4″ or larger handheld portable drill can also be used. This specialized dapping tool is absolutely necessary for the proper installation of the shear plates.
The video above shows how to install a 4″ diameter shear plate for a 3/4″ diameter bolt. The basic instructions are covered below.
Step-by-Step Installation InstructionsView Printer Friendly PDF
You will need:
- 4″ shear plate
- Dapping Tool (kit) including:
- Allen wrench
- 3/4″ pilot bit
- Cutter head
- 13/16″ drill bit
1. Assemble the 3/4″ pilot bit into the cutter head and tighten it with an Allen wrench. Set the dapping tool aside.
These components are included as part of the Dapping Tool Kit supplied by Portland Bolt (product code 18671).
2. Drill a 13/16″ bolt hole in the wood. A drill press is used in the video, but a heavy duty, 3/4″ or larger handheld portable drill will work.
A drill bit is not included as part of the Dapping Tool kit, but can be obtained from any local hardware store.
3. Insert the dapping tool into the handheld drill or drill press. Use the pilot bit to align the cutter head with the pre-drilled bolt hole. Small cap screws on the face of the dapping tool can be adjusted to change the depth of the grooves.
4. When complete, the grooves created by the dapping tool should be at the proper depth so that the face of the shear plate sits flush with the surface of the wood. Adjust the depth accordingly if the shear plate sits too high or too low in the grooves.
It is recommended to start with a very shallow groove and test the depth with the shear plate, adjusting the cap screws until the shear plate sits flush with the wood.
5. In this example, two shear plates are installed between two wooden members. The edge of one board is cut away for demonstration purposes to show the connection. Other installation options exist in which the shear plates are assembled against steel.