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A mortise is a hole cut in timber to receive a tenon and make a joint. This factsheet focuses on floor-mounted and bench-mounted machines found in factories, specifically on the safety of mortisers used to make rectangular holes.
While this guidance has not been updated to reflect current work health and safety legislation (the Health and Safety at Work Act 2015 and regulations), it may still contain relevant information and practices to keep workers and others healthy and safe.
Please read this guidance in conjunction with all relevant industry standards that apply to you as a PCBU. This guidance will be progressively reviewed and either updated, replaced with other guidance, or revoked.
A mortiser has a hollow square-sided chisel with an auger bit inside. The auger cuts a round hole through timber, closely followed by the hollow square-sided chisel, which squares the edges of the hole. One penetration makes a square hole, and repeated penetrations make a rectangular hole. An alternative for rectangular mortises is to use a toothed chain, similar to that from a chain saw.
Figure 1: Mortise
- Contact with chisel, chain or auger
- Impact or contact from moving timber
- Slips, trips & falls
- Contact, impact or entanglement from unexpected movement (during maintenance, cleaning & repairs)
Personal protective equipment (PPE)
- Ear protection
- Eye protection
- Dust protection
Task – Present timber to machine
Contact with chisel, chain or auger
- Deep cuts or amputation
- SECURE guards over chains.
- ONLY USE handles provided to control tools during mortising.
Task – Make the cut
Impact or contact from moving timber
- Timber MUST be securely clamped.
Other (non-mechanical) hazards
- Hearing damage or loss
- REDUCE noise levels by isolating machines or enclosing within noise barriers.
- ASSESS noise levels.
- ARRANGE hearing screenings.
- ALWAYS WEAR hearing protection.
A safe noise level over an eight hour day is 85dB(A). A mortiser may exceed this noise intensity.
- Eye irritation or damage
- Breathing problems, lung damage or cancer
- Worsening of existing health problems
- USE dust extraction equipment to minimise dust getting the operator’s breathing zone.
- ALWAYS WEAR eye protection.
- ALWAYS USE respiratory protection.
Slips, trips and falls
- KEEP up-to-date housekeeping procedures.
- KEEP the area around mortisers clear of slip and trip hazards.
Task – Maintenance, cleaning & repairs
Contact, impact or entanglement from unexpected movement
- LOCK-OUT all power supplies before maintenance, cleaning & repairs.
- ARRANGE regular inspections by a competent person.
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