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Shearing
Industry Consultants |
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| Consultancy | Exercises | Shearing Pattern | Comb Preparation | Manual | Shed Design | Woolhandlers |
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Shearing
Industry Consultants |
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| Consultancy | Exercises | Shearing Pattern | Comb Preparation | Manual | Shed Design | Woolhandlers |
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Sharpening Shearing Gear |
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There are many theories,
opinions, fallacies and rumours about grinding shearing gear. Some are correct, many 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 only, and is based on how many of the world's best performing shearers have their gear sharpened to 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 fibre 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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The Three main points on sharpening shear gear are:
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 AND BASICALLY THAT'S IT, NOTHING COMPLICATED |
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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 - Check which side is the comb emery (Coarse) and which is the cutter emery (Fine) - Ensure safety glasses are present, and use them - Always ensure the grinding discs have stopped spinning before leaving the grinder Check Pendulum Settings - Ensure all nuts and bolts are tight on the pendulum holder - Check the pendulum pins are the correct length - Check the pendulum settings on the grinder before starting motor by; (a) Placing the pendulum rod end on the holder (b) Ensuring the heel of the comb and cutter always touch the disc slightly before the tips (c) Ensuring the pendulum head pressure bar approximate setting is parallel to, and just below the radius of the disc ( If necessary, draw a line with chalk or soft wood from the centre to the outside of the disc) Excessive Heel Grinding Some pendulums are not made to grind shearing combs or cutters correctly, and grind too much off the heel. This causes less metal being removed off the area that is most necessary for cutting wool, and will wear the gear down to the heel (Excessive Heel Grinding) This can be a big problem if it is not corrected early. Use Vernier callipers to check this regularly Grinding combs and cutters flat is what we are after, but excessive tip grinding is better than excessive heel grinding as the gear will always cut |
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Sharpening - Check combs and cutters are properly clean and dry - Spin the discs slightly before turning 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 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 Are the Combs and Cutters SHARP? - Check combs by viewing from the side, turning the cutting edge towards good light. The comb should by ground all over, and check the cutting edges for silver/shiny lines - Check cutters by turning the tips towards good light, they should be ground all over, and check for silver/shiny lines on the tip - A feather edge means it is sharp. Check by rubbing the silver/shiny line on the tooth edge. - If it moves it's a Feather Edge and OK - If it does not move, it is not a Feather Edge and it is Blunt, and needs more steel removed to make it sharp If in doubt grind again |
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Irrelevant information There are many theories, ideas and information from various sources on the Hollow; how it is made, where it should be, how to get it in a certain place etc. Many people have become confused by this and in the end it is all Irrelevant information Just follow the above guidelines and grind enough metal off for a new sharp edge The gear will always cut well if it is sharp, the handpiece is setup and maintained properly, and in good condition
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Three main points on sharpening shearing gear are:
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 More metal removed, is better than less metal removed, it can't be TOO SHARP, but it can be TOO BLUNT |
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| A BLUNT edge below magnified many times |
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A SHARP edge below magnified many times |
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