Dangers of Routing

Not sure how I missed hearing about this, or perhaps it vaguely rings a bell, but I hadn’t delved deeper into the situation.

Back in 2006, a 31 worker was killed in a Cabinet-maker shop in East Bentleigh when the router bit she was using disintegrated and hit her in the chest. (Although what I gather is that with the forces involved, the bit acted more like a bullet than a stone). I don’t know what the resulting ruling against the companies was.

From the WorkSafe website, the following Alert has been re-released April 2010 (read PDF for official document)

WorkSafe Alert – Router Safety

Background – Routers are a common item of fixed plant used in wood machining. They are used to cut, trim and shape materials such as wood, metal and plastic.

A worker was operating an industrial router at a cabinet-making factory when the bit disintegrated and a piece of
metal hit her in the chest. Contributing factors may have included:

  • use of an inappropriate bit for the tool—in this case, a bit with wings too large for the shank;
  • use of a bit with a shank not long enough to be properly grasped in the collet;
  • the tool not being marked with the maximum permissible speed;
  • The tool not being balanced before use.
No etching of the maximum speed
on the side of the bit
Router bit’s wings are too large for shank

Control Measures

  • Ensure that the maximum permissible speed is clearly marked on the tool (preferably by etching).
  • Ensure that the bit is properly balanced prior to being put on the market or into use.
  • Tools should only be sharpened by a competent person or organisation and regular checks of collets should be carried out to ensure they hold router bits firmly.
  • Under no circumstances should local modifications be made to bits or collets to allow the use of non-compatible components.   Staff should be trained and supervised in using these pieces of plant.

Some observations of my own:

The router bit is exceptionally ugly – the design is exceptionally poor – sharp internal corners are very bad stress raisers – this bit should never have been made (IMHO)

The shank on this bit is 20mm, so at 150mm outside diameter, it is a significant router bit

There are no anti-kickback features – you could easily overfeed this bit

I never knew router bits were meant to be etched with a maximum usable speed – something to look out for!

Routers are as dangerous tool as any other major one in the workshop, and deserve equal respect.

Without knowing exactly what happened in this instance, I would be surprised if material wasn’t being fed into the router bit at time it broke.

A very unfortunate, tragic industrial accident.

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