K80v / K120v BOWL CUTTERS
EN-29
REGRINDING AND MAINTENANCE INSTRUCTIONS
FOR ALL GWST BRAND CUTTER KNIVES
The cutter knife is a precision tool and the essence of every cutter, its maintenance
and correct treatment is essential in order to obtain the desired result with regard
to the processed food, better machine operation, longer bearing life, noise and
vibration reduction, etc. Therefore, please pay attention to the following points:
1. Have cutter knives reground by skilled personnel only.
2. Re-grind cutter knives only from the cambered side with a water-cooled whetstone so that original
angle of normal 27 degree is maintained (see sketch).
3. During the re–grinding check that weight and shape of cutter knife´s sets is identical. The deviation
in the weight of the cutter knives should be not more than 5 grams.
4. Following the re-grind, the ground surfaces should be finally ground lengthwise with endless sanding
belts of at least 3 to 3,5 m length to avoid hairline cracks: First with a grain size of 150 then with a
grain size of 240.
5. Polish the cutting edges to high-gloss with a polishing brush (sisal cord brush) and the aid of polishing
paste until they are free of grooves.
6. During all re-grinding work the cutter knives should at no point be heated too much, otherwise you
could get too much stress in material or cracks, which will give later on a breaking of knives. Too
much heat you can see by a yellow-brown to blue temperature colour. This colour, for example the
yellow-brown one, is showing that the cutting edge was heated to about 200°C so that at the grinding
point at the time of grinding must have been a much higher temperature.
7. Deburr and clean cutter knives with a whetstone. Then make a crack examination.
8. Also important is the cleaning of the tightening area, otherwise you will get here pitting corrosions,
which could give later on in the area of vibration a breaking. Also it is possible that there is coming a
chloride-pitting by salt- or water-residues out. Further, also compressive influences based on
sausage´s out can give micro-cracks. When re-grinding knives the cleaning of the whole knife should
be self-evident.
9. The wearing-limit of a cutter knife depends on the kind of working at the cutter and the condition of
the digested material.
10. We recommend working with 2 sets of knives; one set installed on the machine and another perfectly
sharpened set for changeover when regrinding the first set.
TALSA recommends to use professional grinding machines from Knecht (Germany): www.knecht.eu
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