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A mortiser, also known as a hollow chisel mortiser, is a woodworking machine used for creating square or rectangular holes, known as mortises, in wood. These holes are typically useful in joinery tasks such as connecting pieces of wood with a tenon or a dowel. Mortisers are essential in furniture making and cabinetry.

Parts of a Mortiser

Here are the main components of mortisers and how they work:

  • Chisel and Bit: The chisel is a hollow square or rectangular tube, and the bit is a sharp square or rectangular cutting blade that fits inside the chisel. These components work together to remove wood material and create the mortise.
  • Motor: These woodworking machines rely on an electric motor that drives the chisel and bit assembly. The motor provides the necessary power and speed to cut through wood.
  • Table and Fence: A mortiser usually has a sturdy table where the workpiece is placed. A fence helps guide the workpiece and ensure accuracy.
  • Depth Stop: Depth stop mechanisms allow users to set the desired depth for the mortise, allowing for consistency and precision.

Types of Mortisers

When choosing mortisers, consider the scale of the woodworking project, the materials involved, and the desired level of precision. Here are different types of power mortisers, each with its own advantages and applications:

  • Benchtop: This is the most common version and it is designed for mounting on a workbench or a dedicated stand. It is suitable for small to medium-sized woodworking projects.
  • Floor-Standing: Floor-standing mortisers are larger and more powerful than benchtop models. They are designed for heavy-duty tasks and can handle larger workpieces.
  • Chain Mortiser: Chain mortisers are specialized machines that use a chainsaw like chain with cutting teeth to remove material and create mortises. They are useful for timber framing and large-scale woodworking projects.
  • Slot Mortiser: Using slot mortiser bits, these are designed specifically for creating slots or grooves in wood, which are useful for joinery methods including the use of biscuit joiners.
  • Horizontal: This is a variation of the traditional benchtop version. Instead of drilling straight down into the workpiece, they use a horizontal chisel and drill bit arrangement.
  • Multi-Function: Some woodworking machines combine multiple functions. For example a combination machine might include a table saw, jointer, planer, and mortising capability, all in one unit. 
  • CNC Mortiser: Computer Numerical Control (CNC) mortisers are automated machines that use computer programming to create precise and intricate mortises. They are suitable for high-precision and production woodworking environments.

Handling Safety

  • Proper Training: Proper training in handling any power tool is essential for achieving a better quality of work in the safest manner possible.
  • Wear Appropriate Gear: Wear the right work clothes and safety gear. Goggles, hearing protectors, respirators, and gloves, are some of the essentials for woodworking safety.
  • Secure the Workpiece: Use clamps and other fixtures to put the workpiece in place.
  • Adjust Proper Depth: Carefully adjust the depth of the cut as the project requires. This will help prevent over-cutting or under-cutting the material.
  • Keep Hands Away: Never reach into the cutting area while the machine is running or attempting to make a cut. 
  • Use Push Sticks: Use push sticks or push blocks to guide material through the mortiser. This keeps your hands at a safe distance from the cutter.
  • Turn Off When Not in Use: Always turn off the tool’s power and unplug it from the power source before handling for maintenance or blade changes.
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John Friedenbach

My initial goal, to provide a selection of tools, education and plans to the Beginning to Advance Woodworker has not changed. I continue to search the web to find new products and services. To bring those products and services to your attention.

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