A Woodworker’s Notebook
Jeff Gorman
Crown Guards
  • Guards are principally regarded as being simply for the protection of the sawyer's hands, but they also prevent material, including knot fragments and even broken saw teeth from being thrown towards his/her face.
  • Some guards might also hinder the upward progress of a workpiece ejected as a result of a kickback.
  • Even if only one piece is to be sawn, a correctly adjusted guard should be used.
  • Bear in mind that the guard will only be effective while the blade actually embedded in the wood. This can make the final stages of a cut more hazardous.
  • Some guards are mounted on the riving knife. The height of the front of the guard is adjusted by pivoting on a screw fixed to the rear of the guard. This can mean that part of the rear of the blade projecting above the workpiece is exposed.
  • Some people believe that they need to see the cutting edge of the saw, so the guard is either dispensed with or set with too great a gap between the lower edge of the guard and the top of the workpiece. If the wood is being guided by a fence (see Feeding the Workpiece about the risks of freehand cutting), it is the fence that determines the line of cut, hence there is absolutely no need to see the cutting teeth. Attempting to steer the workpiece while the cut is in progress is just asking for trouble. See A Useful Tip
  • The sawyer should always arrange the guard so that the front edge is no more that 12mm (1/2") above the surface of the workpiece (or as closely as practicable if the surface is uneven). To apply this when operating on a variety of workpieces with typical guards is to demand an enormous self-discipline, especially since when using riving-knife-mounted guards fitted with the inadequate wing nuts or small levers, complete safety requires the saw to be stopped and run down between adjustments. (If the guard catches the crown teeth, the guard can be broken and ejected forwards. Please see the adjustable guard illustrated below and note the depth of the guard.
  • American legislation requires self-adjusting guards. The regulation says that 'The hood and mounting shall be arranged so that the hood will automatically adjust itself to the thickness of and remain in contact with the material being cut but it shall not offer any considerable resistance to insertion of material to saw or to passage of the material being sawed'. It appears that poor functioning of some models can be the cause of their removal by exasperated workers.
  • Heaven knows why some makers produce transparent guards. They soon become obscured with dust.
  • The guard can get in the way when ripping narrow sections. The special ripping fence shown in the linked drawing enables the guard to be adequately set yet the workpiece can be reached by the push stick. Some two-position fences can be turned on their sides to achieve the same effect.

The easily-adjusted overarm-supported guard illustrated offers a very worthwhile (albeit no doubt costly) model (extracted from Woodworking Sheet No16 (rev) of the British Health and Safety Executive).

Note the provision for dust extraction. Chips carried round by the blade impair the finish of the cut.

This is a 'Shaw Guard', (illustration also from this HSE sheet) sometimes available as an add-on for professional quality sawbenches. Some models can be fixed directly to the fence. The pressure pad dimensions will need to vary according to the job in hand.

Its function is to form a tunnel guard for use while grooving or rebating, but it is not difficult to see why its requirement will not be popular for workers who use the saw for a variety of cuts. For these tasks, a router table will probably be a far better device.

Efficiently feeding short workpieces of small cross-section can be quite difficult.

A Useful Tip?

Since modern saws blades are used for cutting to fairly precise dimensions, workers do frequently want to make a precise cut aligned with a knife line or pencil mark. For people who generally use only one blade, a very useful dodge can be to accurately indent the table near its front edge with at least one pair of marks, one in line with each side of the teeth.

For guarding work involving grooving, rebating and other jobs that require the removal of the riving knife and crown guard, please seeFences.

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