Circular Saw, Planer and Spindle Moulder Safety

How do accidents happen on woodworking machines?

Circular saw safety is the most critical OHS topic in furniture and woodworking workshops. On these machines the cutting tool rotates at high speed, material is often fed by hand and the operator's hand works a few centimetres from the blade. Serious injuries usually occur through one of three mechanisms:

1. Kickback: The workpiece being cut jams on or rotates against the back teeth of the blade and is thrown towards the operator at high speed. The hand holding the workpiece can be pulled towards the blade at that moment.
2. Direct contact with the blade: On a machine whose guard has been removed or wrongly adjusted, the hand touches the rotating blade or cutter block.
3. The hand slipping during feeding: While a short, thin or irregular piece is being fed, the piece suddenly moves forward or breaks, and the hand slips into the cutting zone.

What these accidents have in common is that guards are removed, not adjusted, or auxiliary aids not used, on the grounds that they "slow the work down". In areas of Bursa where furniture production is concentrated, above all the workshops in and around İnegöl Mobilya Ağaç İşleri İhtisas OSB, these machines are found in every business. Furniture manufacturing (NACE 31.00.01) is in the hazardous class.

Circular saw safety: kickback and the riving knife

The main causes of kickback are: a missing or wrongly adjusted riving knife, a blunt or unsuitable blade, the rip fence wrongly positioned relative to the blade, warped or internally stressed material, and the workpiece being left free at the back of the blade.

Measures:

• The riving knife must always be fitted. The riving knife prevents the cut workpiece from closing and pinching the back teeth of the blade. When the blade is changed, check that the riving knife suits the new blade diameter and kerf width and is set to the distance and thickness values in the manufacturer's manual.
• The top guard must be adjusted. The guard covering the top of the blade is lowered according to the height of the workpiece. A saw with its guard left raised counts as unguarded.
• The rip fence must be correctly positioned. For rip cuts, the fence is set so that the workpiece cannot be trapped between the fence and the blade at the back of the blade.
• The blade must be suitable for the job and sharp. A blunt blade needs more feed force and increases the risk of kickback.
• The operator must not stand in line with the blade. The path of a kicked-back piece is the line of the blade; the operator stands to the side of this line.
• The end of the cut is finished with a push stick. The last part of the workpiece is pushed past the back of the blade with a push stick, not by hand.

Contact with the blade on surface planers and thicknessers

On a surface planer, the cutter block rotates exposed in the table. After the workpiece has passed over the block, the operator's hand passes directly over the cutter block. Most finger amputations happen at this moment.

• Bridge guard: The bridge-type guard covering the unused part of the cutter block is adjusted to the width and thickness of the workpiece. As the workpiece passes, only the part needed for cutting should be exposed.
• Rear guard: The part of the cutter block behind the fence must also be covered.
• Push block: Short and thin pieces are fed not by hand but with a push block with a handle. Very short pieces are not machined on the planer.
• Thicknesser: After feeding the workpiece into the infeed opening, the hand is not put into the opening. The machine's anti-kickback fingers must be in working order. Pieces of different thicknesses are not fed at the same time.

Guarding the spindle moulder

The vertical spindle moulder is one of the riskiest machines in woodworking. The tool rotates at high speed, and the workpiece can easily escape during profiling.

• Guard and pressure combs: The unused part of the tool is covered; pressure combs press the workpiece against the table and fence, preventing the hand approaching the tool.
• Power feed unit: For straight edge work, using a power feed unit is the most effective way of keeping the hand away from the cutting zone.
• Jigs and holders: For curved work, the workpiece is fixed to a jig or holder; the hand holds the jig's handle.
• Feed direction: The workpiece is fed against the tool's direction of rotation. Feeding in the same direction as the tool (climb feeding) causes the workpiece to escape and the hand to be drawn into the tool.
• Speed and tool compatibility: A speed suited to the tool diameter and within the manufacturer's permitted speed range is chosen.

Push sticks and push blocks: when and how?

A push stick does not replace the machine's guards; it complements them. It is used whenever the hand will come close to the blade, and hangs in a fixed place right next to the machine.

Push sticks wear out too. A stick whose end notch is worn, broken or too short cannot hold the workpiece. Set a simple rule: at the start of every shift, check that the push stick and push block are in place and sound.

Keeping guards in use: instructions, training and checks

Having guards fitted is not enough; they must stay in use. The Regulation on Health and Safety Requirements for the Use of Work Equipment requires work equipment to be checked by its operators before each start of work and these checks to be recorded. Annex III of the same regulation provides for periodic inspection once a year for saws and woodworking machines unless the standard sets a shorter interval. We explained the general rules of periodic inspection in our article on work equipment periodic inspection intervals.

Set up the following arrangements on site:

1. Machine instructions: a short, illustrated instruction for each machine showing guard adjustment, auxiliary aids and prohibited operations.
2. Blade and tool changes: before changing, energy is isolated, the machine stops completely and is locked out; the change is made by an authorised person.
3. Daily check: the guard, riving knife, emergency stop, brake and push aids are checked at the start of the shift.
4. Training: only workers trained on that particular machine use it; new workers work under supervision during their first weeks.
5. PPE: eye and face protection, hearing protection and a dust mask. Loose gloves, loose sleeves, rings and jewellery that could wrap around a rotating cutter are not worn.
6. Dust extraction: the extraction system is needed both for health and for visibility; accumulated sawdust also increases the fire load.

You can find the general logic of guard types in our article on machine guards, and the CE and conformity documents to check when buying a new machine in our article on the Machinery Safety Regulation.

Quick checklist for a furniture workshop

During site inspections, check the following for these machines:

• Is the riving knife fitted on the circular saw and suited to the blade diameter?
• Is the top guard adjusted to the workpiece height?
• Is there a bridge guard on the planer, and is it adjusted to the workpiece width?
• Are pressure combs or a power feed unit used on the spindle moulder?
• Are push sticks and push blocks next to the machines and in good condition?
• Are the emergency stop buttons accessible and working?
• Are machine instructions posted and up to date?
• Are periodic inspection reports within the year?

You can find a broader list covering dust, fire, electricity and documentation in furniture workshops in our article on the furniture workshop OHS checklist. We have collected area-specific notes for businesses in İnegöl on our İnegöl OSGB page, and the sector overview on our furniture sector page. For site inspections, machine instructions and the training plan, see our OHS specialist services.

Frequently Asked Questions

Is a riving knife mandatory on a circular saw?

The riving knife is the basic protection against kickback and must be fitted as specified by the machine manufacturer. When the blade is changed, the riving knife's suitability for the new blade must also be checked.

What is kickback and how is it prevented?

Kickback is the cut workpiece jamming on the blade and being thrown towards the operator. A riving knife, an adjusted top guard, a correctly positioned rip fence, a sharp blade, standing to the side of the blade line and using a push stick greatly reduce this risk.

How are short pieces machined on a planer?

Short and thin pieces are fed not by hand but with a push block with a handle. Pieces too short to be held safely are not machined on the planer; they are prepared by another method or cut from a longer piece.

Are gloves worn on woodworking machines?

Loose gloves that could wrap around the cutter are not worn near a rotating blade or tool. If hand protection is needed, the choice is made in the workplace's risk assessment according to the job and the risk.