Craftsman Hardware | Saw Blade Hook Angle

The hook angle is the amount of forward or backward lean each tooth has.  A hook angle can be thought of as the angle at which the tip enters the material.  If the saw tip enters the material at an angle it will be more efficient than if it comes down flat.

A Standard hook angles range from 5 to 15 degrees positive. Steeper angles, from 18 to 22 degrees, are most effective for ripping and cutting softer materials.  Hard materials such as mineral board and sheet plastics, require a shallow angle such as 6 degrees.

To prevent self-feeding, sliding miter saws and radial-arm saws require a blade with a negative tooth angle. Negative hook angles, usually -5 degrees, give the operator maximum control over the feed rate of cut. This is especially important when grooving with the mitre saw, or when dealing with hollow profiles of any material. Due to the negative hook angle, these blades will require a higher tooth count as standard.

It is hard to image troubleshooting something like a blade that has a high feed rate, but it still needs to be done. Any person who has used a saw of any kind, has had some form of an issue that would have required troubleshooting, and problem solving to avoid in the future.

Broken saw blade teeth, compressed clamping plates and off cuts turning into projectiles are all some examples of improper blades being used for purpose.

All of these issues, and the famous lost finger, are often a symptom of improper use or material handling, and we all have to remove the risk. That is why it is important to use the correct blade.

For example, a positive hook angle on a drop saw, as it approaches a smaller piece of timber, will attack it aggressively, and once it has been cut and becomes loose from the workpiece, it will shift inwards towards the blade. The next tooth that touches the offcut, will be flicked towards the fence and then momentum will take over as it bounces off the fence and back towards the operator. Not only is this a hazard for the operator, it also adds the risk of the tooth being knocked, and broken off.

Another example is compressed clamping plates. As a positive hook angle blade is often pulling itself into the workpiece, it is also slowing down when the feed rate is too high. The machine will continue to input the maximum energy possible to turn the blade, as it struggles. This in effect 'turns' the clamping plate on the blade, until it becomes so tight, you may not be able to remove the plate by means of hand tools.