Safe use of metal turning lathes
Metal turning lathes have killed and injured operators. Guidance on this page can help employers identify and control risks from the use of metal turning lathes.
Employers, self-employed persons, employees, designers, manufacturers and suppliers all have legal obligations to workplace safety under the Occupational Health and Safety Act 2004 (OHS Act) and Occupational Health and Safety Regulations 2017 (OHS Regulations).
Fatalities and injuries
Metal turning lathes have been associated with fatalities and serious injuries and both experienced and inexperienced operators have been hurt while operating lathes.
Also known as centre or engine lathes, metal turning lathes are common in the manufacturing industry. The lathes hold metal workpieces and rotate them at high speed while special cutting tools reshape the spinning metal.
Metal turning lathe hazards
The most common causes of death and injury from metal lathes include:
- entanglement of clothing in moving parts, such as drive gears, chucks, lead and feed screws and the workpiece
- being hit by loose objects on the lathe, such as chuck keys, tools or swarf
- entanglement from inappropriate tooling and polishing techniques
- being struck by a workpiece that has not been adequately secured in the lathe or is oversized
Guidance on this page provides examples of the main hazards and risks while using a metal turning lathe. It also includes a list of recommended controls. The zone numbers in the guidance refer to the numbered and coloured zones in the lathe diagram below.
Before introducing the recommended controls, employers should consider what the lathe is used for and whether the control is appropriate for their workplace.
Metal turning lathe risk controls
Zone 1
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Hazard: Workpiece extends beyond the headstock
Risk
During spindle rotation, bar can bend and strike nearby employees.
Recommended controls
- Use workpieces of minimum length to reduce the amount of bar protruding from the headstock.
- Use a bar feed tube to hold workpiece that extends beyond the headstock.
- Guard bar feed weights with hinged covers extending to the floor.
- Modify the lathe speeds (RPM) to ensure bar will not bend when machined.
- Install barriers to stop employees entering space around headstock.
Zone 2
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Hazard: Exposed drive mechanisms, including the pulley, belts and gears
Risk
Employees can become entangled in pulleys, belts or gears when lathe is in operation.
Recommended controls
Ensure exposed drive mechanisms are guarded at the front and back of the lathe.
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Hazard: Lathe controls can only be reached by passing hand through working zone
Risk
Employees can become entangled in unguarded drive mechanisms, chuck, chuck assembly or workpiece when the lathe is in operation.
Recommended control
Ensure controls are within easy access of operator and away from the working zone.
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Hazard: Lack of function markings on controls
Risk
Employees can activate incorrect controls resulting in an unplanned function.
Recommended control
Ensure controls are suitably identified on the lathe to indicate their nature and function.
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Hazard: Placement of controls does not follow the machining process
Risk
Employees can activate incorrect control resulting in an unplanned function.
Recommended control
Ensure operators are adequately trained in what order to use controls.
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Hazard: Unsecured tools and objects stored or placed on the headstock
Risk
Stored objects can fall onto the spinning chuck and be propelled at the operator or nearby employees.
Recommended controls
Ensure headstock is clear and free from clutter.
Do not place items on headstock.
Zone 3
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Hazard: Exposed chuck
Risk
Employees can become entangled on uneven surface of chuck or workpiece when spinning.
Recommended control
Where appropriate, install guarding with interlocking.
Note: Employers must ensure guarding does not stop employees using the lathe in a safe manner or block the view of the task. Where multiple chucks are used, guarding should cover the swing of the lathe, not the size of a chuck.
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Hazard: Chuck key left in chuck
Risk
Employees near lathe can be struck by key propelled from the lathe.
Recommended controls
- Use spring-loaded chuck key.
- Use self-ejecting chuck key.
- Use extended key design that stops interlocked guard being lowered when the key is in the chuck.
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Hazard: Chuck jaws unable to securely clamp the workpiece
Risk
Employees can be struck by workpiece not securely held in the chuck.
Recommended control
Ensure chuck selected is appropriate for the workpiece being machined and meets manufacturer specifications.
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Hazard: Chuck has not been adequately secured to the spindle
Risk
Employees can be struck by chuck not securely held in the spindle.
Recommended control
Use retaining nut with left-hand thread.
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Hazard: Mounting and removing heavy chucks and faceplates
Risk
Employees can sustain musculoskeletal or crushing injuries when changing heavy chucks and faceplates.
Recommended control
Use overhead crane or mounted lifting aid.
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Hazard: Use of a chuck that is not compatible with lathe and/or task specifications
Risk
Use of incorrect chucks can result in the chuck or workpiece becoming loose and striking employees.
Recommended controls
- Ensure chuck rating is within required rating for the lathe.
- Ensure chuck is compatible with lathe and/or task specifications.
- Use independent chuck for gripping round, square or irregular-shaped work or un-machined work requiring heavy cutting. An independent chuck has greater gripping power than a self-centring chuck.
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Hazard: Chucks and faceplates used on the lathe are damaged or have catch points
Risk
Employees can become caught on chucks and faceplates that are poorly maintained or have protrusions.
Recommended controls
- Ensure chucks and faceplates are selected or designed so there are no catch points, particularly where 'homemade' designs are used.
- Ensure chucks and faceplates are set up to manufacturer/supplier specifications.
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Hazard: Oversized workpiece in self-centering chuck, also known as a three-jaw chuck
Risk
Chuck jaws in full extension to allow for oversized workpieces can be propelled from the lathe when operated or become a point of entanglement due to extended parts sticking out.
Recommended controls
Use appropriate-sized chuck for turning workpiece.
Zone 4
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Hazard: Objects, for example, cutting tools and swarf, unsecured on carriage and tool post
Risk
Unsecured objects can become projectiles when the lathe is started, possibly striking employees.
Recommended controls
- Ensure nothing is unsecured on carriage.
- Ensure guarding is placed on the carriage, where appropriate.
Zone 5
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Hazard: Worn or damaged tools being used on the lathe
Risk
Use of worn or damaged tools can result in tool failure and can become projectiles or create irregular or long cuttings that can lead to lacerations.
Recommended control
Ensure worn or damaged tools are removed and not used.
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Hazard: Exposed lead and feed screws. An assessment of risk will need to include the speed at which the lead and feed screws travel
Risk
Employees can become entangled in exposed lead and feed screws when the lathe is in operation, particularly if the lathe is being used by a number of users with various levels of experience, for example, in a learning institution.
Recommended control
Where appropriate, ensure lead and feed screws are guarded.
Zone 6
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Hazard: Unguarded protrusions on the workpiece
Risk
Employees can become entangled on protrusions on the workpiece being turned.
Recommended control
Where possible, ensure the area of the working zone where access is not necessary is guarded.
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Hazard: Coupling and clamps used on the lathe are damaged or have catch points
Risk
Employees can become caught on coupling and clamps that are poorly maintained or have protrusions.
Recommended controls
- Ensure couplings and clamps are selected or designed so there are no catch points, particularly where 'homemade' designs are used.
- Ensure couplings and clamps are set up to manufacturer/supplier specifications.
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Hazard: Unsupported workpieces
Risk
Unsupported workpieces can become loose, striking employees.
Recommended controls
Use fixed or travelling steadies to support long, slender workpieces between centres or to support outer end of long piece held in chuck for drilling or boring.
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Hazard: Machining process produces continuous or unravelled cuttings
Risk
Employees can become entangled in turning cuttings.
Recommended controls
- Consider appropriate cutting speeds, feed rate and chip thickness during task planning.
- Use lathe tools with chip breakers of the gullet or step type.
- Ensure appropriate personal protective equipment is provided and used correctly.
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Hazard: Removing metal shavings, cuttings and swarf from machining area with hands
Risk
Unprotected handling of shavings, cutting and swarf can result in lacerations.
Recommended control
Ensure swarf handles and buckets are used when cleaning swarf, shaving and cuttings from lathe.
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Hazard: Neighbouring workspaces are exposed to swarf, cuttings or workpieces during the machining process
Risk
Swarf, cuttings or workpieces can become projectiles and strike nearby employees, causing injuries such as lacerations and fractures.
Recommended control
Ensure guarding is placed around lathe.
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Hazard: Frequent traffic, both human and machinery, passing through the work area near the operator
Risk
While operating the lathe, the operator can be bumped or startled by passing traffic, causing the operator to come into contact with the lathe.
Recommended controls
- Ensure the lathe is located in an area that has little to no traffic.
- Use suitable barriers to stop employees/vehicles not using the lathe from unnecessarily entering the area. Barriers should not stop employees moving workpieces on or around the lathe.
- Create a restricted zone around the lathe operator during machining. The restricted zone must be supported with a clearly communicated policy and signs.
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Hazard: Incorrect methods used for polishing workpieces with emery cloth
Risk
Employee can become entangled in the lathe.
Recommended controls
Ensure emery cloth is applied using:
- backing board or good quality wood
- tool post to place the cloth on
- 'nutcracker' consisting of two backing boards lined with emery cloth and joined at one end. They are shaped to allow the surface to be linished.
- Hold emery cloth only by ends, never to be used wrapped around hands or all the way around the workpiece.
- Ensure speeds (RPM) are not excessive.
- Ensure there are no protruding bolts or counter weights on the workpiece.
General hazards, risks and controls
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Hazard: Lack of or poorly placed emergency stop button or pedal to bring lathe to immediate standstill
Risk
Operator is unable to stop the lathe in case of an emergency.
Recommended control
Ensure a red-coloured emergency stop button/pedal is present and identifiable and can be reached by employees from all positions when operating the lathe.
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Hazard: Loose clothing, cuffed or rolled back sleeves, neckties, jewellery, including watches, and long hair
Risk
Loose clothing, accessories and hair can become entangled in moving parts of the lathe, chuck assembly or workpiece.
Recommended controls
- Ensure close-fitting clothing with no catch points is worn by operators.
- Ensure jewellery, including watches, rings, bracelets, chains, is removed before operating the lathe.
- Ensure long hair is tied back by tie or hairnet.
Environment
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Hazard: Inappropriate type and position of lighting
Risks
The flashing effect of fluorescent light can make a spinning lathe appear to have stopped. This can lead to employee entanglement.
Lighting placed over the lathe can be struck by projectiles from the machining process. Employees nearby can be injured by the light shattering.
Recommended controls
- Workstations should be lit with lights that do not produce a flashing effect, for example, incandescent lights.
- Lighting should not be positioned where it can be damaged. If damage is a risk, lighting should be protected.
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Hazard: Untidy and unorganised working environment
Risks
Employees can slip or trip on cutting oils, swarf or cuttings that are not cleaned from the floor.
Employees can also trip over lathe parts or workpieces that are not returned to storage areas.
Recommended controls
- Ensure liquids and cuttings are cleaned from the floor as soon as possible after they spill or are produced.
- Ensure lathe parts and workpieces are returned to storage areas when they are no longer being used.
Training and supervision hazards
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Hazard: Poorly trained and supervised operators machining on the lathe
Risk
Employees who are inexperienced, lack training or adequate supervision are at risk of injuring themselves and others by becoming entangled in moving parts of the lathe or using poorly fitted chucks and work pieces that can become projectiles.
Recommended controls
- Ensure all operators are appropriately trained and competent before beginning work on the lathe.
- Ensure inexperienced operators are supervised by a competent person.
- Display safe operating procedures at the lathe.
Maintenance and repair hazards
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Hazard: Lack of power isolation switch that can be locked out
Risks
Employees can become entangled in the lathe if it is accidentally activated during maintenance and repairs.
Recommended controls
Ensure a lockable isolation switch is present on the lathe.
Ensure standard operating procedures exist for maintenance and repair of the lathe.
Personal protective equipment hazards
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Hazard: Wearing gloves while using the lathe
Risk
Gloves can become caught in moving parts when using or cleaning the lathe.
Recommended control
Ensure gloves are not worn when operating or cleaning the lathe.
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Hazard: Operating the lathe without safety glasses
Risk
Shavings, cuttings and swarf may be ejected from the lathe and make contact with employees' eyes.
Recommended control
Ensure employees wear safety glasses when operating the lathe.
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Hazard: Working on heavy workpieces or lathe parts without steel-capped safety shoes
Risk
Employees without personal protective footwear may be exposed to a crushing foot injury if heavy workpieces or lathe parts are being moved.
Recommended control
Ensure employees wear steel-capped safety shoes or boots when operating the lathe.