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Sharpening Shearing Gear |
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There are many theories,
opinions, fallacies and rumors about grinding shearing gear. Some are correct some are
incorrect,
and others are deceitful and fabricated by inexperienced people.
Sometimes to
protect or sell a product, other times it's just plain don't know.
This document has facts and is based on how many of the world's best performing shearers set records, or perform every day well ahead of others in the industry. Grinding is an important part of shearing, and we grind combs and cutters for one reason only, to get them sharp. There are no degrees of sharpness where fiber gets cut on comb and cutter edges. They are either sharp or blunt. Many shearers are limited because of poor grinding technique or equipment. Some shearers blame the sheep, the handpiece, the make of combs or cutters, and other things, when the fault maybe incorrect grinding and as a result their gear may not be sharp. Following are some important points that may help if you have a problem. |
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Three main points on sharpening shear gear:
1 - The heel of comb and cutter must touch the disc before the tip 2 - Remove enough metal to make a new sharp edge 3 - When finishing near the outside of the disc, ensure the sparks travel from the centre of the comb and cutter up the pendulum rod |
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Safety
- Ensure the grinder is out of a traffic area - Ensure there is adequate room around the grinder - Ensure there is adequate light for checking gear is sharp - Check the power cord is in a safe condition - Check the grinder is on a solid base and cannot tip over or move - Check Emery Papers are correctly glued, trimmed and not torn or lifted - Check the nuts are tight on the discs - Ensure there are safety glasses present - Always ensure the grinding discs have stopped spinning before leaving the grinder Pendulum Settings - Ensure all nuts and bolts are tight on the pendulum holder - Check which side is the comb emery (Coarse) and which is the cutter emery (Fine) - Check the pendulum pins are the correct length - Check the pendulum settings on the grinder before starting motor (a) Place the pendulum rod end on the hanger (b) The heel of the comb and cutter should always touch the disc slightly before the tips (c) The pendulum head pressure point should be parallel to and just below the radius of the disc ( Draw a line with chalk or soft wood from the centre to the outside of the disc) |
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| Sharpening
- Spin the discs slightly and turn the grinder on - Once the grinder is at the full speed, place the pendulum on the pendulum holder - Place a comb or cutter on the pendulum, - Sheep side, to the pendulum head, grinding side to the grinder disc - Bring the pendulum to the disc and ensure the comb or cutter touches the disc even on each side. - Place firm but not heavy pressure on the pendulum and move from the inside to the outside and back - Ensure the comb or cutter does not go off the edge of the disc, as it may catch if the edge is rough - Do this for a few passes maybe 6 for a cutter and 12 for a comb (More may be necessary) - When on the last pass, stop just in from the outside of the disc and ensure the sparks are travelling straight off the centre teeth and up the pendulum rod. (Up or down adjustment may be necessary) - Hold in this position for a few seconds then take off and check the side of the teeth - Be careful that it is not too hot when you touch it - A feather edge means it is sharp. Check by rubbing the silver line on the tooth edge. If it moves it's a feather and OK - If it is not a feather edge it is blunt, and needs more steel removed. If in doubt grind again |
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| Remember the
Three main points on sharpening shearing gear:
1 - The heel of comb and cutter touches the disc before the tip 2 - Remove enough metal to make a new sharp edge 3 - When finishing near the outside of the disc, ensure the sparks travel from the centre of the comb and cutter up the pendulum rod More metal removed is better than less, it can't be too sharp, but it can be blunt |
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