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Chipper Knife Holders

by Dipak Patil
Chipper Knife Holders


Chipper knife holders are manufactured from various sizes of steel bars (M-1020 or A-36).

Manufacturing Process

  1. Steel bars are cut to desired length.
  2. Bars are then skinned flat and squared, then the correct angle is machined on one side per OEM specifications.
  3. After inspection of bars being skinned correctly, then they are drilled and counter-bored for the desired chipper on CNC machinery.
  4. Holders are then roughed out to desired shape with excess stock in order for CNC machining to finish at OEM tolerances.
  5. Last, the back bar of the holder is machined down to OEM specifications.

Life of Holders

The normal life expected will be approximately one year based on a five-day workweek of an eight hour workday. For example, if it is used 16 hours per day, it would have about six months of life. If it is used 24 hours a day, it would mean four months of life, provided material feeding into chipper has been de-barked and cleaned!

Dirty material does NOT wear the same as ‘CLEAN’ wood. Therefore, the life of the unit is not anywhere close to life expectations of ‘CLEAN’ wood.

This is based on the assumption that the chipper pocket is in correct tolerance of flatness, width and cleaned properly when the chipper components are replaced. Also, the unit should be free of ‘WRECKS’, which will cause the chipper assemblies not to clamp correctly, during operation of the chipper allowing the complete pocket assembly to ‘ROCK’ during operation, which leads to packing between ‘ALL’ areas of the chipper components (holder, counter knife, knife and knife clamp, and also under the holder).

Counter Knives

The counter knife should be new when replacing a holder. Never use old counter knives with new holders.

Care must be utilised when installing by ensuring the holder is clean and the counter knives are correctly seated in the knife holder – this is extremely important.

Chipper Knives

The chipper knives should be in good condition whenever they are replaced by checking for the minimum width requirements. Checking for ‘RIPPLED KNIVES’ is important – this is the number one problem of a chipper packing. Rippled knives are chipper knives that are not worn the same distance from the sharp edge of the chipper knife back to the base of the knife, caused by allowing the counter knives to be utilised too long and ‘NOT’ changing them on a regular basis. A rippled knife will have a dip along the length of the knife that is not the same. If rippled knives are used, they must be replaced or corrected to remove the ripple area of the chipper knives.

Good Knife

Rippled Knife

Rippled knives can be corrected, provided they have sufficient width left on the knife. To correct, chipper knives will have to be ground in order for the counter knife to fit on new and unaffected area of the knife.

Salestech is the specialist for customer-specific solutions. For recommendations or customisation to meet your requirements, speak to our team today. Call 03 9553 1883 or email Alternatively, you can speak to our support agents via LiveChat on our website, from 8.30am to 12 noon, weekdays.