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You should seek a knowledgeable sharpener to re-grind your chipper knives. Although a lot of people believe they are doing it right they do not use the proper grinding wheels or enough coolant. Besides the obvious additional wear on equipment improper sharpening can cause a safety hazard if done incorrectly. We at TSK know the importance of doing it right. Below is a general listing that sharpeners need to be familiar with when sharpening chipper knives.
Chipper Knife Care
- All Brush Chipper Knives must be re-sharpened to the specified OEM bevel angles (degrees) for best performance.
- Asplundh: 40 degrees
- Salsco: 31 degrees
- Bandit: 31 degrees
- Dosko: 37½ degrees
- Valby: 30 degrees
- Woodsman: 31 degrees
- Vermeer: 30 / 40 degrees (varies)
- Woodchuck: 31 / 42 degrees (varies)
- Morbark: 31 degrees
- Before sharpening, make sure each knife is flat. You must discard all knives that are bent, bowed, or have the bolt holes puckered out from over tightening. If you use a knife with this condition the knife will wood pack, causing major damage.
- Use a soft "H," "I," or "J" grade grinding wheel with an open 36 to 46 grain structure.
- Plenty of coolant must be used at all times when re-sharpening. Do not get the knife hotter than you can touch with your bare hands. Overheating will destroy the knife, causing it to crack.
- Do not "snag" sharpen the knife with a hand-held disc grinder. Inconsistent grinding pressure without ample coolant will cause heat cracks on the cutting edge.
- Hand hone all burrs off the cutting edge after grinding with a 150 / 240 grit honing stone. If you leave burrs on the cutting edge it will decrease the sharpening life.
- Do not over tighten the knife mounting bolts or nuts. Over tightening beyond the manufacturer's recommended foot / pounds will cause the knife to crack from the mounting holes of the knife out to the cutting edge.
- Do not mount any knife in a dirty or unflat pocket or holder. If the knife is tightened up against an unflat surface, it will bend, break, or crack the knife.
- Do not operate your chipper with dull knives. Dull knives take more power to drive the dull cutting edge through the wood and can cause knife and mounting bolt failure.
- Do not re-sharpen a knife beyond the manufacturer's recommended minimum width. The knife has a tough (softer) center area with harder cutting edges for safety.
- Insist on knives made by a reputable manufacturer that certifies the knife is made out of 8 percent chrome A8 Modified chipper knife tool steel.
This bulletin was drafted by The KnifeSource LLC.
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