In Junkkari chippers it is very easy to adjust the knifes steplessly and modify the chip size according your needs. But there are certain things which you should keep in mind regarding a good chip quality.

Condition of the knifes

If the knifes are not sharp, cutting of the wood needs more power and the chip quality decreases. Wearing of the knifes depends highly of the material what you chip, how clean it is etc. It is good idea to have at least one set of extra knifes in stock to avoid loss of time due to sharpening. Also try to avoid feeding sandy or muddy wood which has been laying on the soil. Remember that sharpening needs to be done with proper tools and angle must be 30,5 degrees. 

The counter knifes don't need service as often as the cutting knifes but you should also check their condition frequently. Their angle is not so critical, just make sure that they are straight and distance between knife and counter knife is equal for the entire length. The counter knifes always wear faster from the outer edge and it makes them curvy.

Distance between knife and counter knife

Please make sure that distance between counter knifes and knifes is as small as possible, about 1mm. If the distance is too big, the work is not efficient, and the wood is breaking instead of cutting nicely.

Feeding

Also, the way how you feed the material to the chipper has some effect on the chip quality. It is always useful to avoid the last piece of wood slipping alone from the rollers towards the knifes and disc. It helps if the wood is fed continuously, so that the next wood is guiding or supporting the previous one when it passes the feeding rollers. Sometimes this requires temporary stop of the feeding rollers but if chip quality is important, this can be useful thing to do.

Brush wood knifes

In all Junkkari chippers, it is possible to mount the brush wood knifes on top of the normal cutting knifes on the disc. This improves the chip quality especially if you use thin branches and other complicated material. It basically adds small knifes to make opening in the disc smaller and thin material can't slip through without cutting. In bigger models, HJ320 and HJ500 you can also add the brush wood knifes to the chamber for another additional cutting tools. Both type of the brush knifes naturally increase the power demand and therefore they are not normally used with bigger logs.

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