When to choose a square (hollow chisel) bit

A square bit is suitable when you need to:

• create a precise square or rectangular mortise,
• produce classic mortise and tenon joints,
• achieve repeatable precision in serial production,
• maintain traditional structural wood joint construction.

If you only need a round hole, choose another type of drill bit. This tool is designed exclusively for producing square holes.

Where square bits are used in practice

They are mainly used:

• in solid wood furniture production,
• in the manufacture of frames, doors and windows,
• in stair production and structural joints,
• in joinery workshops and custom manufacturing.

Square bits are primarily intended for use in mortising machines.

With the help of an adapter, they can also be used in bench or drill press machines that have suitable construction and sufficient rigidity. The adapter ensures stable tool guidance and expands the capabilities of a standard drill press to include mortise production.

How to work with square bits

A square bit consists of two parts:

• an internal auger bit that pre-drills a round hole,
• an outer hollow square chisel that cuts the sharp corners and forms the final square shape.

The correct interaction between these two parts is essential for cutting quality.

Use a suitable machine

They are primarily intended for mortising machines. If used with a drill press, it is necessary to use a suitable adapter and verify machine compatibility (such as spindle diameter and sufficient clearance for the chisel holder).

Detailed information about installation, compatibility and correct use can be found in the product description of the Adapter for square mortise bits.

They are not intended for handheld or cordless drills.

Set the correct speed

Use lower speeds than for standard drilling. Higher speeds may cause overheating, vibrations and reduced edge quality.

Work step by step

Remove material gradually. Do not attempt to cut the entire mortise in a single pass, as this may overload the tool or cause deviation.

Secure the workpiece firmly

The material must be securely clamped. The process involves significant load, and improper fixation may affect joint quality.

Limitations and what to watch out for

Square (hollow chisel) bits are not intended for standard drilling operations or use without rigid guidance.

Incorrect clearance between the auger bit and the hollow chisel, or the use of an unsuitable machine, may lead to increased wear and reduced cutting quality.