- Starting the “Grinder Motor” stops the feed for approx. 5 seconds to allow time for the grinding wheel to spin up to operating speed.
- Introducing the grinding wheel to the teeth requires a coordinated adjustment of both the Feed Position Knob and the Height Adjusting Knob – grinding more from the front face will take the grinding wheel away from the back of the tooth and vice versa.
- Grind only the minimum from the front face of the teeth. Altering the tooth’s front face shape or hook may require readjusting the feed pawl height to suit the new form.
- Bi-metal blades have a very small high speed steel tips that disappear after successive grinds. Their run time between sharpening is reduced once the high speed steel is removed.
- A clean, smooth blade surface is required for consistent grinding -- remove any rust or gum from the blade. Applying a light coat of “water dispersant” to the blade aids uniform feed.
- Heat is the enemy when it comes to cutting accuracy as it expands the blade’s leading edge, causing loss of rigidity and wandering. Ideally the heat generated in cutting should be removed with the sawdust and not retained in the blade. Keeping the blade sharp and cutting enables the teeth to discharge heat in the sawdust.
- When cutting, the available power at the blade is consumed in many ways including (1) penetration (2) bending & shearing the chip (3) accelerating the chip and (4) friction between the blade & chip. The teeth’s geometry is important in maximising the blade’s performance. Teeth must be sharp but strong enough to maintain set and resist deformation in the cut. As a general rule, the angle of “keenness” (sharpness) must be between 40º and 50º to allow the teeth to penetrate easily. For example, 10º hook - 45º tooth included angle - 35º clearance. Increasing the hook should see a commensurate decrease in the clearance. 20º hook -45º tooth included angle - 25º clearance.
- Low hook angles are less efficient as they use more power to accelerate the chip down the tooth’s face and increase friction but narrow blades are generally not sufficiently rigid to cope with hook angles much higher than 12º-15º especially when there are knots -- 10º hook is generally a good starting point.
- Become familiar with using the machine in the standard, straight sharpening mode before progressing to MSA sharpening.
- When sharpening in MSA mode, it is preferable that blades are joined so that the teeth set holds its sequence through the join (total teeth number is dividable by 3). Should this not be the case, sharpening must start and stop at the join in the blade. Place a magnet on the join; when this passes the reed switch, the machine will automatically stop, providing the counter is at its default value. (1).
- The tooth pitch at the join should be similar to the rest of the blade – variation in pitch will change the tooth’s profile but not the tooth’s height. Outsized pitch may not allow the feed pawl to engage the following tooth.
Blades with MSA sharpened teeth do not require as much set because:
1. The chip is not directed immediately under the tooth but away into the gullet.
2. The tooth is pulled out to the side and not pressed in.