Overhand planing machines
Named for the position of the hands of the operator, an overhand planing machine is a horizontal cylindrical cutter block set between two tables, with knives secured in the cutter block. It is sometimes called a “jointer”, because in making flat edges it prepares timber for jointing edge-to edge to make wider boards.
The outfeed table is set higher than the infeed table because of the thickness of the cut, to keep the timber steady. Timber is passed by hand from the infeed table, across the cutters, to the outfeed table.
Cylindrical cutters minimise the gap between tables. Cylindrical cutter blocks have been compulsory in New Zealand for several decades. Square cutter blocks are no longer used, as they are considered hazardous due to the risk of ejected cutters.
Figure 1: Overhand planing machine
- Contact with cutters
- Contact or impact from thrown timber
- Slips, trips & falls
- Contact, impact or entanglement from unexpected movement (during maintenance, cleaning & repairs)
Personal Protective Equipment (PPE)
- Ear protection
- Foot protection
- Dust protection
- Deep cuts or amputation
- FIX guarding.
- KEEP the opening between the end of the guard and the timber as small as possible.
- DO NOT put hands on timber directly above the cutters.
- HOLD short pieces of timber with a push block, with handles on the side away from the timber, and a shoulder to push the timber (see figure 2).
- If braking time is greater than 10 seconds, RETROFIT braking.
Guarding should include:
A bridge guard (easily adjusted without using tools) above the cutters, with a width of 1 1/2 times the width of the opening for the cutters. A guard over the cutter block behind the fence.
- KEEP cutters sharp so their energy is used to cut, not push against the timber.
- Present timber AGAINST the direction of the cutters.
- When timber is passed UNDER the guard, the opening above the timber MUST be as closed as possible.
- When timber is passed BETWEEN the guard and the fence, the opening between the end of the guard and the timber MUST be as small as possible. The guard should be NO MORE THAN 10 mm above the table.
- When timber is dropped on for returns, cut- outs or chamfers, there MUST be a backstop clamped to the fence on the infeed table to control kick-back.
- POSITION the planer to prevent timber from hitting other people.
Figure 2: Push block used with short piece of timber
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). An overhand planing machine 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 in the operator’s breathing zone.
- ALWAYS USE respiratory protection.
- ALWAYS WEAR eye protection.
- KEEP up-to-date housekeeping procedures.
- KEEP the area around mortisers clear of slip and trip hazards.
Task – Maintenance, cleaning & repairs
- LOCK-OUT all power supplies before maintenance, cleaning and repairs.
- ENSURE that people carrying out maintenance, cleaning or repairs are aware of significant overrun after power is turned off.