Safe use of metal turning lathes
This guidance is for employers. It can help to identify and control risks to help keep employees safe while operating 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 can cause death or serious injuries to operators.
Also known as centre or engine lathes, metal turning lathes are common in the manufacturing industry.
Lathes hold metal workpieces and spin them at high speed. Special cutting tools reshape the spinning metal.
Metal turning lathe hazards and risks
This guidance gives examples of the main hazards and risks while using a metal turning lathe.
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 secured properly in the lathe.
- being struck by a workpiece that is too big for the lathe.
Under Section 21 (1) of the Occupational Health and Safety Act 2004, an employer must, so far as is reasonably practicable, provide and maintain for employees of the employer a working environment that is safe and without risks to health.
The employer or self-employed person must ensure, so far as is reasonably practicable, that guarding designed for that purpose will prevent access to the danger area of the plant (OHS Regulations 99(2).
An employer must control any risk associated with the use of plant in the workplace so far as reasonably practicable (OHS Act s21(2)(a) and OHS Regulations r98).
This guidance includes a list of controls that may be used to help keep employees safe while operating lathes.
Zones 1 to 6, in Metal turning lathe risk controls, refer to the numbered and coloured zones in figure 1.
Before introducing the controls, employers should consider what the lathe is used for and if the control is appropriate for their workplace. This includes considering:
- if the lathe is the most appropriate plant for the task
- if the operators are suitably competent to do the task.
Additional controls that are above and beyond the industry norm, and those outlined here, may be appropriate when the lathe is used in a learning environment with users of low knowledge and experience.
Metal turning lathe risk controls
Zone 1
- Hazard: Workpiece extends beyond the headstock
Risk
During spindle rotation, the bar can bend and strike nearby employees.
Control
- Use workpieces of minimum length to reduce the amount of bar protruding from the headstock. Where the bar protrudes, use a bar feeder system or support stands to secure the bar during machining.
- Use a bar feeder system or support stands to hold the bar securely during machining.
- Guard bar feed weights with hinged covers extending to the floor.
- Ensure the lathe speed is appropriate for the material being machined.
- Consider the type of material, its physical particulars and its dimensions.
- Install barriers around the protruding workpiece and its support. This can help prevent employees touching the rotating workpiece during operation.
Zone 2
- 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.
Controls
Ensure exposed drive mechanisms are guarded at the front and back of the lathe. The guard cover should be interlocked to prevent any unsafe access.
- Hazard: Lathe controls can only be reached by passing hand through working zone
Risk
Employees can become entangled in unguarded drive mechanisms, the chuck, the chuck assembly or the workpiece when the lathe is in operation.
Control
Ensure controls, such as the light switch, and equipment such as a coolant hose, are within easy access of the operator and away from the working zone.
- Hazard: Lack of function labels on control panel
Risk
Employees can activate incorrect controls resulting in an unplanned function.
Control
All operating controls must be clearly labelled with its correct function.
- Hazard: Placement of controls does not follow the machining process
Risk
Employees can activate the wrong control resulting in an unplanned function.
Control
Ensure operators are adequately trained in the correct sequence for using controls.
You must provide employees with any necessary information, instruction, training or supervision to enable them to perform their work in a way that is safe and without risks to health.
Where a hazard associated with plant is identified, you must ensure employees using the plant are provided with information and instruction on hazard identification and risk control, safety procedures, safe use of personal protective equipment (PPE).
- Hazard: Unsecured tools and other 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.
Controls
- Ensure the headstock is clear and free from clutter.
- Do not place items on the headstock.
Zone 3
- Hazard: Exposed chuck
Risk
Employees can become entangled on the uneven surface of the exposed chuck or workpiece.
Control
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. Guarding should account for the size of the largest chuck where multiple chucks are used, as well as the swing of the workpiece and the chuck jaw.
- Hazard: Chuck key left in chuck
Risk
Employees near the lathe can be struck by the chuck key if propelled from the lathe.
Controls
- Use a self-ejecting, spring loaded chuck key.
- Use an extended key design that stops the interlocked guard being lowered when the key is in the chuck.
- Hazard: Chuck jaws unable to securely clamp the workpiece
Risk
Employees can be struck by the workpiece that is not securely held in the chuck.
Control
Ensure the chuck selected is appropriate for the workpiece being machined and meets the manufacturer specifications.
- Hazard: Chuck has not been adequately secured to the spindle
Risk
Employees can be struck by the chuck that is not securely held in the spindle.
Control
- Check the locking mechanism specific to the chuck.
- Ensure it is used as per manufacturer and supplier recommendations.
- Check that the chuck is securely fastened before use.
- Hazard: Mounting and removing heavy chucks and faceplates
Risk
Employees can sustain musculoskeletal or crushing injuries when changing heavy chucks and faceplates.
Control
Use an overhead crane or mounted lifting aid.
- 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.
Controls
- Ensure the chuck rating is within the required rating for the lathe.
- Use the best suited chuck for the task. For example, use a 4 jaw chuck for irregular shapes, and a 3 jaw chuck for round work pieces.
- 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.
Controls
- Ensure chucks and faceplates are selected or designed so there are no catch points, particularly where custom designs are used. Note: where custom designs are used, they need to be designed and fabricated by suitably competent persons.
- Ensure chucks and faceplates are set up to manufacturer and supplier specifications.
- Hazard: Oversized workpiece in self-centering chuck, also known as a three-jaw chuck
Risk
Chuck jaws in full extension allow for oversized workpieces — these can be propelled from the lathe when spinning or they can become a point of entanglement due to the extended parts sticking out.
Controls
Use the most appropriate chuck for the task. This includes configuring the jaws of the chuck to best suit the task and the work piece. For example, reverse the jaws so there is maximum scroll on each jaw.
Zone 4
- 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.
Controls
- Ensure everything is secured on the carriage.
- Ensure guarding is placed on the carriage, where appropriate.
Zone 5
- 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.
Control
- Ensure worn or damaged tools are not used.
- Ensure worn or damaged tools are removed from the workplace.
- Hazard: Exposed lead and feed screws
The planning of the task will need to include consideration for the speed at which the lead and feed screws travel.
Where tasks such as thread cutting and the automatic feeds of the carriage is required, 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 several users with various levels of experience. For example, in a learning institution.
Control
Where appropriate, ensure lead and feed screws are guarded.
Zone 6
- Hazard: Unguarded protrusions on the workpiece
The employer or self-employed person must ensure, so far as is reasonably practicable, that guarding designed for that purpose will prevent access to the danger area of the plant (OHS Regulations 99(2)).
Risk
Employees can become entangled on protrusions on the workpiece being turned.
Control
Review the danger area and consider if it is possible to guard the area. Where it is not reasonably practicable to guard, then ensure there is a suitable combination of administrative controls to manage the risk. This includes planning the task, ensuring that the operator is suitably competent and experienced and providing supervision where necessary.
- 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.
Controls
- Ensure couplings and clamps are selected or designed so there are no catch points, particularly where custom designs are used.
- Ensure couplings and clamps are set up to manufacturer and supplier specifications.
- Hazard: Unsupported workpieces
Risk
Unsupported workpieces can become loose and strike employees.
Controls
Use fixed or travelling steadies to support long, slender workpieces between centres, or to support the outer end of the long piece held in the chuck for drilling or boring.
- Hazard: Machining process produces continuous or unravelled cuttings
Risk
Employees can become entangled in turning cuttings.
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 (PPE) is provided and used correctly.
- Hazard: Removing metal shavings, cuttings and swarf from machining area with hands
Risk
Unprotected handling of shavings, cutting and swarf can result in lacerations.
Control
Ensure swarf handles and buckets are used when cleaning swarf, shaving and cuttings from lathe. Note: This task should only be done when the lathe is not in use.
- 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.
Control
Ensure guarding is placed around lathe.
- Hazard: Frequent traffic, both human and machinery, passing through the work area and 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.
Controls
- Ensure the lathe is located in an area that has little to no traffic.
- Use suitable barriers to stop employees — who are not using the lathe —and vehicles from unnecessarily entering the area. Barriers should not obstruct employees using the lathe from 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.
- Hazard: Incorrect methods used for polishing workpieces with emery cloth
An emery cloth should never be held or applied by hand to a rotating workpiece.
Risk
Employee can become entangled in the lathe.
Controls
Never hold or apply an emery cloth by hand to a rotating workpiece.
Ensure the emery cloth is applied using a:
- backing board or good quality wood
- tool post to place the cloth on
- 'nutcracker' consisting of 2 backing boards lined with emery cloth and joined at one end. They are shaped to allow the surface to be linished.
General hazards, risks and controls
- 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 during an emergency.
Control
If the lathe includes an emergency stop button or pedal, the employer should ensure that:
- the stop device is prominent, clearly and durably marked and immediately accessible to each operator of the plant
- any handle, bar or push button associated with the device is coloured red, and
- the device cannot be adversely affected by electrical or electronic circuit malfunction.
- 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 the moving parts of the lathe, chuck assembly or workpiece.
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 with a tie or hairnet.
Environment
- 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.
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.
- Also, ensure the on/off switch is located away from a danger zone. Position the switch in a safer place, to the side of the work zone of the lathe, for example.
- 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.
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
Employers have a legal duty to provide employees with any necessary information, instruction, training or supervision to enable them to perform their work in a way that is safe and without risks to health (OHS Act s21(2)(e)).
- Hazard: Poorly trained and supervised operators machining on the lathe
Risk
Employees who are inexperienced, without training or adequate supervision are at risk of injuring themselves and others. They may become entangled in moving parts of the lathe or use poorly fitted chucks and work pieces that can become projectiles.
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
- 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.
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
- Hazard: Wearing gloves while using the lathe
Risk
Gloves can become caught in moving parts when the lathe is operating.
Control
Ensure gloves are not worn when using a lathe that is operating.
- Hazard: Metal shavings, cuttings and swarf
Risk
Shavings, cuttings and swarf may be ejected from the lathe and make contact with employees' eyes.
Control
Ensure employees wear safety glasses when operating the lathe.
- 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.
Control
Ensure employees wear steel-capped safety shoes or boots when operating the lathe.