- Location
- N.Lincs
Narrow Combs
Shearing Shop,sheep shearing machines,handpieces,combs,cutters,clothing,spares,Lister Shearing,Heiniger,Shearing clothing
www.hornershearing.com
shearing hand piece knowledge for dummies
- Thread starter spin cycle
- Start date
I reckon they might fit the best one of the 2 of mine, ..
......thats if I can get it moving reasonably well without completely stripping it down
??
JD-Kid
Member
- Location
- Akaroa.. New Zealand
dont let the Aussies. get started on narrow combs there were punch ups and gun fights over narrow and wide combs in aussie union strikes black listings all kinds of dramas
grandfather had a old lister with 2 forks for it. a narrow and wide the bed were the combs attach suited both narrow and wide combs
grandfather had a old lister with 2 forks for it. a narrow and wide the bed were the combs attach suited both narrow and wide combs
CHAPTER 6
HARVESTING EQUIPMENT, PREPARATION AND MAINTENANCE
6.1 Machine Shearing
6.1.1 Harvesting Equipment
Although the modern handpiece appears to be a solid piece of machinery, it is a delicate precision tool.
The outer casing is a steel casting carefully machined to very fine tolerances, while moving parts are formed from specially hardened steel.
6.1.1.1 Setting Up The Handpiece
Select the most suitable comb for the job. Ensure that the comb and cutters to be used are properly ground.
Make sure the comb bed of the handpiece is properly cleaned. Place the comb on the handpiece and set it with the ground fact against the comb bed using one of the comb screws to secure it for the moment.
Turn the handpiece right side up and slip the cutter under the forked yokes, ensuring the pins sit in the holes in the cutter. Apply just enough tension to stop the cutter falling out.
Now adjust the position of the comb to get the correct lead and throw. The cutter should extend far enough each side to just cover the outside teeth on the comb. Secure the comb again so it will not slip.
Check again that the cutter is not placing any pressure on the comb before finally tightening the comb screws.
Recheck the lead and throw, then apply shearing tension to the cutter. The tension can be "fine tuned" when the handpiece is fitted to the dropper and the machine started. The handpiece should just turn in your hand when you relax your grip.
Note: If the tension is too loose it might be dangerous as the cutter may fly off or lock up the handpiece. It may also allow the wool get between the cutter and comb and will not then cut effectively, even if subsequently tightened. If the tension is too tight the handpiece will overheat and cause excessive comb and cutter wear.
6.1.1.2 Lubrication
The body or barrel of the handpiece contains one small oil reservoir which may need filling with clean grade 30 oil every two hours. At the same time, put a few drops of oil on the comb surface, the fork yoke sleeves, the tension pin cup, the crank roller and a squirt of oil down the ferrule on the back joint.
Periodically putting grease in the tension sleeve should complete an adequate lubrication job.Note: Do not put grease inside the tension nut.
Any sign of overheating around the tension nut will signal a lack of lubrication. Similarly, overheating around the post can generally be fixed by placing a drop of oil on the centre post.
6.1.1.3 Fault Finding
It is rare that a handpiece malfunctions except as the result of an accident which has damaged it. But there is a gradual deterioration in performance over time as the working parts wear.
Ninety percent of supposed handpiece malfunctions are due to poorly ground gear. First ensure that your combs are evenly ground over the whole surface with no white hairlines visible on the cutting edges. Cutters must be evenly ground over the whole surface with no dull tips.
Check the performance of the handpiece with properly sharpened gear before taking any other corrective measures.Next remove the comb screws, clean the comb bed and visually check that the comb bed is perfectly flat. Also check there is no wool caught in the cups. Ensure the fork yokes swivel freely in the fork.
If none of the above faults are evident it may be time to replace any worn parts.
Figure 6.4 Comb
Look for white lines on the cutting edges. These are actually rounded edges not quite ground out. Also check that there are no score marks on the combs. If faults are apparent repeat procedure.
6.1.1.4 Replacing Parts
Figure 6.5 Parts requiring regular replacement
There are some parts of the handpiece that require regular replacement. After wearing out a string of 50 cutters, which is the normal number a professional shearer would carry per handpiece, you should replace the tension sleeve, the tension pin and top cup. The centre post and bottom cup should also be replaced.
Fork yokes, back cogs, joint guard and drive pin will require periodic replacement.
There are three essential safety parts on any handpiece. NEVER operate a handpiece without them. They are there for the shearer's protection. They are the tension spring, the fork yoke retaining bar and the tension pin retaining spring.
Tension Spring
The tension spring should be working properly, stopping the tension gradually coming off. Without the spring unnecessary tension is often used and accelerates the speed at which gear wears, requiring a major gear grinding job.
If a new spring is too tight, remove it and squeeze it up before refitting. This will allow it to retain tension without making it so tight that it makes changing cutters difficult.
Figure 6.6 Parts requiring periodic replacement
Fork Yoke Retaining Bar
This bar is designed to secure the fork yokes to the fork.
Tension Pin Retaining Spring
This simply holds the tension pin in place. The handpiece is unsafe to use without it in place as the pin could slip while changing cutters. Note: Absence of an effective tension spring will contribute to lockups.
Figure 6.7 Essential parts
It is dangerous to operate any handpiece without them.
Centre Post and Cup
With normal use the back of the post wears against the back of the bottom cup to form a smooth complementary pivot surface. Once this surface is created, it is most important that the post is not moved from its original working position.
The only time the post should be adjusted is when you are installing a new post and bottom cup. You would normally replace the centre post and bottom cup when you are setting up a new supply of cutters.
With the handpiece set up with a comb and half worn cutter the correct setting is when one third of the crank roller is visible above the fork body when you look down the barrel from the cutter end. On a new handpiece the centre post is normally correctly set but should be checked.
Once it is bedded into the cup the centre post SHOULD NOT be adjusted.
The Comb Bed or Baseplate
The handpiece is a piece of precision machinery which can be easily distorted by rough treatment. Constant dropping on the floor, being kicked from the shearer's hand to smash against the wall or other maltreatment can bend the comb bed. This is a serious fault and is best fixed by sending the body of the handpiece to a suitably equipped engineer or agent who specialises in handpiece repairs.
A correctly aligned bed will be parallel to the screw bushing and at 90 degrees to the tension bushing.
If the comb bed is damaged, it must be repaired by a qualified shearing engineer.
6.1.1.5 Safety Tips
Do not operate the handpiece with badly worn fork yoke pins or when the fork yokes are sloppy inside the fork sleeves.
Do not start the handpiece without checking that:
- The comb screws are firmly tightened (note: excessive tightening will eventually strip threads in the handpiece body).
- The fork yoke pins are securely located in the cutter holes.
- The correct starting tension is applied. Using the thumb on the back cogs, move the cutter across the surface of the comb. A safe
starting tension will leave a good impression of the cogs on your thumb.
6.1.1.6 The Spline Drive/Pin Option
The traditional connection of the handpiece onto the down tube has been a pin drive. Another option which is becoming popular with some shearers is a spline drive.
This has an important safety benefit if the shearer hits an ear tag, piece of wire or the handpiece locks up for some other reason.
When operating with a spline drive, the handpiece usually unlocks from the gut before any serious damage occurs. With a pin drive, a lock-up will normally result in expensive breakages and possible loss of work through injury.
Many machines are not fitted with spline drives. Safety conscious shearers can overcome this by carrying their own appropriate short gut and fitting it into the machine before they start. Don't forget to retrieve it at the end of the job though!
6.1.1.7 Dressing a New Comb
Dressing a comb should always be done in good light and involves shaping the teeth to the ideal profile. This should be done before the comb is ground and requires three stages.
1. Shape the bevel to the desired profile using a piece of fine emery working from the back of the comb over to the cutting face aiming at a high rounded point. There are three common faults which should be avoided:
(A) Too round: will not enter the wool properly and tends to ride out of the wool.
(B) Dropped point: with a tooth of this shape skin cuts will occur.
(C) Squared off points: will not enter the wool easily and skin cuts will occur.
(D) The correct shape: the most important part of dressing a comb is the finish. All teeth must be dressed to the same shape and
must also follow an even concave.
2. When the bevels are finished, the next step is to fine the bottom edge of the bevel (the edge that runs along the skin) down to approximately the thickness of the edge of a postcard.
Good fine teeth mean better combing. Using a fine wedged slip stone, emery or a tapered spinning disc grinder called a bright boy, start from the back of the tooth and work around to the point, taking care not to alter the point which has just been formed nor to go too far and damage the cutting edge of the comb. DO NOT OVERTHIN.
As illustrated, if the teeth have not been thinned, they will ride off the skin causing second cuts (A);
The comb best suited to quality work is where the tips have a fine white line around the end of the tooth (B);
Over thinning will cause skin cuts (C).
3. To get a smooth finish, use 1200 grade wet and dry sandpaper then check bevel fineness to make sure all the teeth are of the same thickness.
Polish the teeth by rubbing on a leather strap, an old rubber tyre or a machine buffer. Use polishing compound for a good shiny finish. Polishing combs helps to stop the greasy building up and allows for smoother entry and running.
When you've completed dressing and polishing combs grind them ready for shearing.
Dressing a Worn Comb
When combs are ground down so that the scallop grinds out and they become too sharp to use, repeat the process for dressing a new comb.
Each time the comb grinds out to a sharp tip, redressing is required. The teeth get shorter and slightly rounder each time. Note: Be careful not to sand along cutting edges.
6.1.1.8 Grinding
Grinding is an extremely important part of shearing. It requires a high degree of precision and care. Shearers often blame their handpieces, the sheep or themselves for their difficulties. Often poor grinding technique or faulty machinery can be the cause.
Safety
- The grinder should be placed away from doorways and steps.
- It should be in a well-lit area with easy access for grinding.
- Never leave the grinder running unattended.
- Check the pins on the pendulum for length.
- Guards must be fitted to the grinder.
- The use of safety glasses is essential. (Carry a pair in your tool kit).
- Always check nuts are tight before turning grinder on.
Note: A grinder can be lethal. Do not rush when grinding, use common sense and safety equipment - for your own sake and the sake of others in the shed.
The Pendulum
The exclusive use of a good pendulum on a correctly set grinder will ensure reliable and efficient grinding at all times.
Pendulum Maintenance
The bottom bar of the pendulum applies pressure to the comb or cutter during grinding and it is essential that it is true. If the bar has the corners ground off, it will not give an accurate grind.
The recommended setting between the pressure bar and pins is 4 mm; a closer setting will heel grind; a wider pin setting will tip grind.
Make sure that the pins are long enough so that they maintain a hold on the comb or cutter.
- When not in use store so that the pendulum rod does not bend.
- Use a metal strip on the magnetic bar to retain magnetism.
Heel Grinding
Heel grinding results from use of pendulums where the pin settings are closer than the recommended 4 mm. To avoid tip grinding a small bevel may be removed from the heel of the comb.
Excessive heel grinding is not recommended because it:
- Prevents sufficient grinding pressure being applied to the tips of the comb to sharpen cutting surfaces properly.
- Creates excessive flexibility in the heel of the comb.
- Affects the contact of the comb screws on the comb.
The Hollow Grind
The face of the grinder disc is shaped to give a very slight hollow grind between heel and tip of combs and cutters. This is essential to bring the cutting edges of the comb and cutter together properly under pressure.
Grinder Setting
The height setting of the pendulum is very important to produce the hollow grind on the face of the comb or cutter. When the pendulum rod is handing straight, a vertical flow of sparks from the tips will indicate the correct settings.
Using the hook to suspend the pendulum, the heel of the comb or cutter should touch the disc just before the tips. With the pendulum hanging straight, the magnetic bar should hand 25 mm from the outer edge of the disc.
Combs:
Combs should be ground on the coarse paper (40 grade) with the bottom tooth of the comb towards the outside of the disc. After ensuring the pins of the pendulum are in the holes of the comb, put the comb to the disc. Using a firm even pressure move the comb five or six times (six to eight seconds) across the paper, making sure it does not run off the edge or into the centre of the disc. Before removing the comb, hold it still with an even pressure for 2-3 seconds with the pendulum rod straight.
- Ensure that the sparks are even right across the comb.
- Remember too much pressure overheats and distorts the comb.
After grinding, check combs by looking across the teeth from side to side in good light.
Cutters:
Follow the same procedure as with combs using an even lighter pressure and reduce to two to four passes (3-4 seconds) across fine paper (80 grade).
Cutters should be ground evenly over the whole surface with no dull tips. If there are any faults repeat procedure.
Should be ground evenly over the whole surface with no dull tips or white hair lines on the edges of the teeth.
Figure 6.19 Cutters
Check that cutters are grinding down evenly on both sides. Also ensure that each cutter is wearing at the same rate. Rotating on a wire or cutter holder will help. The handpiece will work better and last longer if the cutters wear down at an even rate. For a full time professional shearer a string of 50 cutters is recommended.
If there are any faults after the check repeat the grinding procedure and recheck.
6.1.1.10 Grinding Equipment
Setting Papers:
Always store papers in dry conditions. Ensure that the disc is clean, free from old glue and dry. Place new paper on clamp. Spread glue onto the disc evenly and sparingly, then clamp the paper firmly but without excessive pressure. A thin flat sheet of cardboard between the emery and the clamp will reduce the crushing of the emery grit.
Care of Papers:
Do not grind first thing in the morning or when the atmosphere is damp. When the papers are partly worn they can be revived by using a rubber cleaning stick and a light stroke with a carborundum stone or wire brush. Light, even grinding will also make papers last longer.
Grinder Maintenance:
Although discs are made of cast steel, they can be distorted by rough treatment or wear and tear.
- When not in use for long periods store discs on the clamps.
- Check that the back of the disc and the area where it connects to the grinder are clean when mounting discs.
- The centre of the paper should be cut out and any excessive glue cleaned away.
- Always use washers when setting paper and mounting discs on grinder.
- These machines are for sharpening shearing gear and should not be used as bench grinders.
- Discs in need of repair can be refaced and rebalanced by engineers specialising in shearing equipment.
Note: For best results, use your own grinder all the time or carry your own discs from shed to shed. Always use your own pendulum.
HARVESTING EQUIPMENT, PREPARATION AND MAINTENANCE
6.1.1 Harvesting Equipment
Although the modern handpiece appears to be a solid piece of machinery, it is a delicate precision tool.
The outer casing is a steel casting carefully machined to very fine tolerances, while moving parts are formed from specially hardened steel.
6.1.1.1 Setting Up The Handpiece
Select the most suitable comb for the job. Ensure that the comb and cutters to be used are properly ground.
Make sure the comb bed of the handpiece is properly cleaned. Place the comb on the handpiece and set it with the ground fact against the comb bed using one of the comb screws to secure it for the moment.
Turn the handpiece right side up and slip the cutter under the forked yokes, ensuring the pins sit in the holes in the cutter. Apply just enough tension to stop the cutter falling out.
Figure 6.1 |
Now adjust the position of the comb to get the correct lead and throw. The cutter should extend far enough each side to just cover the outside teeth on the comb. Secure the comb again so it will not slip.
Check again that the cutter is not placing any pressure on the comb before finally tightening the comb screws.
Recheck the lead and throw, then apply shearing tension to the cutter. The tension can be "fine tuned" when the handpiece is fitted to the dropper and the machine started. The handpiece should just turn in your hand when you relax your grip.
The distance between the base of the scallop and the tip of the cutter. Note: Lead should never be less than 2 mm. Insufficient lead is the main cause of skin cuts. Always use more lead in full wool, fine wool or when using thinner combs. |
Figure 6.2 Lead |
Note: If the tension is too loose it might be dangerous as the cutter may fly off or lock up the handpiece. It may also allow the wool get between the cutter and comb and will not then cut effectively, even if subsequently tightened. If the tension is too tight the handpiece will overheat and cause excessive comb and cutter wear.
6.1.1.2 Lubrication
The body or barrel of the handpiece contains one small oil reservoir which may need filling with clean grade 30 oil every two hours. At the same time, put a few drops of oil on the comb surface, the fork yoke sleeves, the tension pin cup, the crank roller and a squirt of oil down the ferrule on the back joint.
Periodically putting grease in the tension sleeve should complete an adequate lubrication job.Note: Do not put grease inside the tension nut.
Any sign of overheating around the tension nut will signal a lack of lubrication. Similarly, overheating around the post can generally be fixed by placing a drop of oil on the centre post.
6.1.1.3 Fault Finding
It is rare that a handpiece malfunctions except as the result of an accident which has damaged it. But there is a gradual deterioration in performance over time as the working parts wear.
Ninety percent of supposed handpiece malfunctions are due to poorly ground gear. First ensure that your combs are evenly ground over the whole surface with no white hairlines visible on the cutting edges. Cutters must be evenly ground over the whole surface with no dull tips.
These partially ground edges show up as dull tips or white hair lines on the edges of the teeth.
Figure 6.3 Cutter
Figure 6.3 Cutter
Check the performance of the handpiece with properly sharpened gear before taking any other corrective measures.Next remove the comb screws, clean the comb bed and visually check that the comb bed is perfectly flat. Also check there is no wool caught in the cups. Ensure the fork yokes swivel freely in the fork.
If none of the above faults are evident it may be time to replace any worn parts.
Look for white lines on the cutting edges. These are actually rounded edges not quite ground out. Also check that there are no score marks on the combs. If faults are apparent repeat procedure. |
Figure 6.4 Comb
Look for white lines on the cutting edges. These are actually rounded edges not quite ground out. Also check that there are no score marks on the combs. If faults are apparent repeat procedure.
6.1.1.4 Replacing Parts
Figure 6.5 Parts requiring regular replacement
There are some parts of the handpiece that require regular replacement. After wearing out a string of 50 cutters, which is the normal number a professional shearer would carry per handpiece, you should replace the tension sleeve, the tension pin and top cup. The centre post and bottom cup should also be replaced.
Fork yokes, back cogs, joint guard and drive pin will require periodic replacement.
There are three essential safety parts on any handpiece. NEVER operate a handpiece without them. They are there for the shearer's protection. They are the tension spring, the fork yoke retaining bar and the tension pin retaining spring.
Tension Spring
The tension spring should be working properly, stopping the tension gradually coming off. Without the spring unnecessary tension is often used and accelerates the speed at which gear wears, requiring a major gear grinding job.
If a new spring is too tight, remove it and squeeze it up before refitting. This will allow it to retain tension without making it so tight that it makes changing cutters difficult.
Figure 6.6 Parts requiring periodic replacement
Fork Yoke Retaining Bar
This bar is designed to secure the fork yokes to the fork.
Tension Pin Retaining Spring
This simply holds the tension pin in place. The handpiece is unsafe to use without it in place as the pin could slip while changing cutters. Note: Absence of an effective tension spring will contribute to lockups.
Figure 6.7 Essential parts
It is dangerous to operate any handpiece without them.
Centre Post and Cup
With normal use the back of the post wears against the back of the bottom cup to form a smooth complementary pivot surface. Once this surface is created, it is most important that the post is not moved from its original working position.
The only time the post should be adjusted is when you are installing a new post and bottom cup. You would normally replace the centre post and bottom cup when you are setting up a new supply of cutters.
With the handpiece set up with a comb and half worn cutter the correct setting is when one third of the crank roller is visible above the fork body when you look down the barrel from the cutter end. On a new handpiece the centre post is normally correctly set but should be checked.
Once it is bedded into the cup the centre post SHOULD NOT be adjusted.
Worn post and cup 
Do not adjust post once it is worn Figure 6.8 New post and cup |
The Comb Bed or Baseplate
The handpiece is a piece of precision machinery which can be easily distorted by rough treatment. Constant dropping on the floor, being kicked from the shearer's hand to smash against the wall or other maltreatment can bend the comb bed. This is a serious fault and is best fixed by sending the body of the handpiece to a suitably equipped engineer or agent who specialises in handpiece repairs.
A correctly aligned bed will be parallel to the screw bushing and at 90 degrees to the tension bushing.
Comb bed and tension bushing should be at right angles. Comb bed and screw bushing should be parallel.
Figure 6.9 |
If the comb bed is damaged, it must be repaired by a qualified shearing engineer.
6.1.1.5 Safety Tips
Do not operate the handpiece with badly worn fork yoke pins or when the fork yokes are sloppy inside the fork sleeves.
Do not start the handpiece without checking that:
- The comb screws are firmly tightened (note: excessive tightening will eventually strip threads in the handpiece body).
- The fork yoke pins are securely located in the cutter holes.
- The correct starting tension is applied. Using the thumb on the back cogs, move the cutter across the surface of the comb. A safe
starting tension will leave a good impression of the cogs on your thumb.
6.1.1.6 The Spline Drive/Pin Option
The traditional connection of the handpiece onto the down tube has been a pin drive. Another option which is becoming popular with some shearers is a spline drive.
This has an important safety benefit if the shearer hits an ear tag, piece of wire or the handpiece locks up for some other reason.
When operating with a spline drive, the handpiece usually unlocks from the gut before any serious damage occurs. With a pin drive, a lock-up will normally result in expensive breakages and possible loss of work through injury.
Many machines are not fitted with spline drives. Safety conscious shearers can overcome this by carrying their own appropriate short gut and fitting it into the machine before they start. Don't forget to retrieve it at the end of the job though!
6.1.1.7 Dressing a New Comb
Dressing a comb should always be done in good light and involves shaping the teeth to the ideal profile. This should be done before the comb is ground and requires three stages.
1. Shape the bevel to the desired profile using a piece of fine emery working from the back of the comb over to the cutting face aiming at a high rounded point. There are three common faults which should be avoided:
(A) Too round: will not enter the wool properly and tends to ride out of the wool.
(B) Dropped point: with a tooth of this shape skin cuts will occur.
(C) Squared off points: will not enter the wool easily and skin cuts will occur.
(D) The correct shape: the most important part of dressing a comb is the finish. All teeth must be dressed to the same shape and
must also follow an even concave.
2. When the bevels are finished, the next step is to fine the bottom edge of the bevel (the edge that runs along the skin) down to approximately the thickness of the edge of a postcard.
Good fine teeth mean better combing. Using a fine wedged slip stone, emery or a tapered spinning disc grinder called a bright boy, start from the back of the tooth and work around to the point, taking care not to alter the point which has just been formed nor to go too far and damage the cutting edge of the comb. DO NOT OVERTHIN.
As illustrated, if the teeth have not been thinned, they will ride off the skin causing second cuts (A);
The comb best suited to quality work is where the tips have a fine white line around the end of the tooth (B);
Over thinning will cause skin cuts (C).
3. To get a smooth finish, use 1200 grade wet and dry sandpaper then check bevel fineness to make sure all the teeth are of the same thickness.
Polish the teeth by rubbing on a leather strap, an old rubber tyre or a machine buffer. Use polishing compound for a good shiny finish. Polishing combs helps to stop the greasy building up and allows for smoother entry and running.
When you've completed dressing and polishing combs grind them ready for shearing.
Figure 6.10 Common Faults |
Figure 6.11 Thinning the teeth | 
Figure 6.12 Comb Tip |
Dressing a Worn Comb
When combs are ground down so that the scallop grinds out and they become too sharp to use, repeat the process for dressing a new comb.
Each time the comb grinds out to a sharp tip, redressing is required. The teeth get shorter and slightly rounder each time. Note: Be careful not to sand along cutting edges.
6.1.1.8 Grinding
Grinding is an extremely important part of shearing. It requires a high degree of precision and care. Shearers often blame their handpieces, the sheep or themselves for their difficulties. Often poor grinding technique or faulty machinery can be the cause.
Safety
- The grinder should be placed away from doorways and steps.
- It should be in a well-lit area with easy access for grinding.
- Never leave the grinder running unattended.
- Check the pins on the pendulum for length.
- Guards must be fitted to the grinder.
- The use of safety glasses is essential. (Carry a pair in your tool kit).
- Always check nuts are tight before turning grinder on.
Note: A grinder can be lethal. Do not rush when grinding, use common sense and safety equipment - for your own sake and the sake of others in the shed.
Top magnetic bar is slightly shorter than lower pressure bar so that the heel of the comb or cutter always touches the disc first.
Figure 6.13 The Pendulum | Bottom view of the pendulum bar showing corners ground off. This will prevent an accurate grind.
Figure 6.14 A damaged holder will not grind properly |
The Pendulum
The exclusive use of a good pendulum on a correctly set grinder will ensure reliable and efficient grinding at all times.
Pendulum Maintenance
The bottom bar of the pendulum applies pressure to the comb or cutter during grinding and it is essential that it is true. If the bar has the corners ground off, it will not give an accurate grind.
The recommended setting between the pressure bar and pins is 4 mm; a closer setting will heel grind; a wider pin setting will tip grind.
Make sure that the pins are long enough so that they maintain a hold on the comb or cutter.
- When not in use store so that the pendulum rod does not bend.
- Use a metal strip on the magnetic bar to retain magnetism.
Heel Grinding
Heel grinding results from use of pendulums where the pin settings are closer than the recommended 4 mm. To avoid tip grinding a small bevel may be removed from the heel of the comb.
Excessive heel grinding is not recommended because it:
- Prevents sufficient grinding pressure being applied to the tips of the comb to sharpen cutting surfaces properly.
- Creates excessive flexibility in the heel of the comb.
- Affects the contact of the comb screws on the comb.
The Hollow Grind
The face of the grinder disc is shaped to give a very slight hollow grind between heel and tip of combs and cutters. This is essential to bring the cutting edges of the comb and cutter together properly under pressure.
Grinder Setting
The height setting of the pendulum is very important to produce the hollow grind on the face of the comb or cutter. When the pendulum rod is handing straight, a vertical flow of sparks from the tips will indicate the correct settings.
Using the hook to suspend the pendulum, the heel of the comb or cutter should touch the disc just before the tips. With the pendulum hanging straight, the magnetic bar should hand 25 mm from the outer edge of the disc.
| The Disc has a half degree fall from centre to edge. This produces a hollow grind in the gear from heel to toe. |
Figure 6.15 Grinding disc
6.1.1.9 Grinding ProcedureCombs:
Combs should be ground on the coarse paper (40 grade) with the bottom tooth of the comb towards the outside of the disc. After ensuring the pins of the pendulum are in the holes of the comb, put the comb to the disc. Using a firm even pressure move the comb five or six times (six to eight seconds) across the paper, making sure it does not run off the edge or into the centre of the disc. Before removing the comb, hold it still with an even pressure for 2-3 seconds with the pendulum rod straight.
- Ensure that the sparks are even right across the comb.
- Remember too much pressure overheats and distorts the comb.
After grinding, check combs by looking across the teeth from side to side in good light.
The HEIGHT SETTING of the pendulum is therefore MOST IMPORTANT.
A vertical glow of sparks indicates the ideal setting.
A vertical glow of sparks indicates the ideal setting.
| Pendulum rod must hand parallel to disc with the heel of the comb or cutter touching first. | Edge of magnetic head should hang 25 mm from edge of disc. | Pins must swing just under the centre of the shaft for cutters and to the bottom of the shaft for combs. |
Figure 6.16
Combs: Cross section of one tooth, shows original sharp edge rounded with use. 
| Partially ground edges show up as white hairlines on the edges of the teeth. 
|
| Figure 6.18 Worn combs |
Follow the same procedure as with combs using an even lighter pressure and reduce to two to four passes (3-4 seconds) across fine paper (80 grade).
Cutters should be ground evenly over the whole surface with no dull tips. If there are any faults repeat procedure.
Should be ground evenly over the whole surface with no dull tips or white hair lines on the edges of the teeth.
Figure 6.19 Cutters
Check that cutters are grinding down evenly on both sides. Also ensure that each cutter is wearing at the same rate. Rotating on a wire or cutter holder will help. The handpiece will work better and last longer if the cutters wear down at an even rate. For a full time professional shearer a string of 50 cutters is recommended.
If there are any faults after the check repeat the grinding procedure and recheck.
6.1.1.10 Grinding Equipment
Setting Papers:
Always store papers in dry conditions. Ensure that the disc is clean, free from old glue and dry. Place new paper on clamp. Spread glue onto the disc evenly and sparingly, then clamp the paper firmly but without excessive pressure. A thin flat sheet of cardboard between the emery and the clamp will reduce the crushing of the emery grit.
Care of Papers:
Do not grind first thing in the morning or when the atmosphere is damp. When the papers are partly worn they can be revived by using a rubber cleaning stick and a light stroke with a carborundum stone or wire brush. Light, even grinding will also make papers last longer.
Grinder Maintenance:
Although discs are made of cast steel, they can be distorted by rough treatment or wear and tear.
- When not in use for long periods store discs on the clamps.
- Check that the back of the disc and the area where it connects to the grinder are clean when mounting discs.
- The centre of the paper should be cut out and any excessive glue cleaned away.
- Always use washers when setting paper and mounting discs on grinder.
- These machines are for sharpening shearing gear and should not be used as bench grinders.
- Discs in need of repair can be refaced and rebalanced by engineers specialising in shearing equipment.
Note: For best results, use your own grinder all the time or carry your own discs from shed to shed. Always use your own pendulum.
- Location
- Dumfries & Galloway
tbh honest the David Fagan utube vid has s a bit more simplerway he just calls the 'center line' just the base of the tooth on the comb and same on the cutter ...that lines up with the spindle centre, tbh im on sharpening skill improvement today, a lthough i do wonder if my old 12 inch wheel will do such a good job as the modern bigger one,Pfft, so technical...
This is how the pro's do it, just watch your fingers
gear not been going so well, son had to stop for it too many times .... so i need to up my game... or buy more cutters and combs...
- Location
- N.Lincs
Pfft, so technical...
This is how the pro's do it, just watch your fingers
Looks like a good way to feck up your combs and cutters - not to mention your finger ends
Think I'll keep sending mine to Horners.
Tubbylew
Member
- Location
- Herefordshire
Fek u wouldn't want to let him loose on a box of heinigers!Pfft, so technical...
This is how the pro's do it, just watch your fingers
clod hopper
Member
- Location
- SHREWSBURY, shropshire
Did you get all that Spin!CHAPTER 6
HARVESTING EQUIPMENT, PREPARATION AND MAINTENANCE
6.1 Machine Shearing
6.1.1 Harvesting Equipment
Although the modern handpiece appears to be a solid piece of machinery, it is a delicate precision tool.
The outer casing is a steel casting carefully machined to very fine tolerances, while moving parts are formed from specially hardened steel.
6.1.1.1 Setting Up The Handpiece
Select the most suitable comb for the job. Ensure that the comb and cutters to be used are properly ground.
Make sure the comb bed of the handpiece is properly cleaned. Place the comb on the handpiece and set it with the ground fact against the comb bed using one of the comb screws to secure it for the moment.
Turn the handpiece right side up and slip the cutter under the forked yokes, ensuring the pins sit in the holes in the cutter. Apply just enough tension to stop the cutter falling out.
Figure 6.1
Now adjust the position of the comb to get the correct lead and throw. The cutter should extend far enough each side to just cover the outside teeth on the comb. Secure the comb again so it will not slip.
Check again that the cutter is not placing any pressure on the comb before finally tightening the comb screws.
Recheck the lead and throw, then apply shearing tension to the cutter. The tension can be "fine tuned" when the handpiece is fitted to the dropper and the machine started. The handpiece should just turn in your hand when you relax your grip.
The distance between the base of the scallop and the tip of the cutter.
Note: Lead should never be less than 2 mm.
Insufficient lead is the main cause of skin cuts. Always use more lead in full wool, fine wool or when using thinner combs.
Figure 6.2 Lead
Note: If the tension is too loose it might be dangerous as the cutter may fly off or lock up the handpiece. It may also allow the wool get between the cutter and comb and will not then cut effectively, even if subsequently tightened. If the tension is too tight the handpiece will overheat and cause excessive comb and cutter wear.
6.1.1.2 Lubrication
The body or barrel of the handpiece contains one small oil reservoir which may need filling with clean grade 30 oil every two hours. At the same time, put a few drops of oil on the comb surface, the fork yoke sleeves, the tension pin cup, the crank roller and a squirt of oil down the ferrule on the back joint.
Periodically putting grease in the tension sleeve should complete an adequate lubrication job.Note: Do not put grease inside the tension nut.
Any sign of overheating around the tension nut will signal a lack of lubrication. Similarly, overheating around the post can generally be fixed by placing a drop of oil on the centre post.
6.1.1.3 Fault Finding
It is rare that a handpiece malfunctions except as the result of an accident which has damaged it. But there is a gradual deterioration in performance over time as the working parts wear.
Ninety percent of supposed handpiece malfunctions are due to poorly ground gear. First ensure that your combs are evenly ground over the whole surface with no white hairlines visible on the cutting edges. Cutters must be evenly ground over the whole surface with no dull tips.
These partially ground edges show up as dull tips or white hair lines on the edges of the teeth.
Figure 6.3 Cutter
Check the performance of the handpiece with properly sharpened gear before taking any other corrective measures.Next remove the comb screws, clean the comb bed and visually check that the comb bed is perfectly flat. Also check there is no wool caught in the cups. Ensure the fork yokes swivel freely in the fork.
If none of the above faults are evident it may be time to replace any worn parts.
Look for white lines on the cutting edges. These are actually rounded edges not quite ground out.
Also check that there are no score marks on the combs. If faults are apparent repeat procedure.
Figure 6.4 Comb
Look for white lines on the cutting edges. These are actually rounded edges not quite ground out. Also check that there are no score marks on the combs. If faults are apparent repeat procedure.
6.1.1.4 Replacing Parts
Figure 6.5 Parts requiring regular replacement
There are some parts of the handpiece that require regular replacement. After wearing out a string of 50 cutters, which is the normal number a professional shearer would carry per handpiece, you should replace the tension sleeve, the tension pin and top cup. The centre post and bottom cup should also be replaced.
Fork yokes, back cogs, joint guard and drive pin will require periodic replacement.
There are three essential safety parts on any handpiece. NEVER operate a handpiece without them. They are there for the shearer's protection. They are the tension spring, the fork yoke retaining bar and the tension pin retaining spring.
Tension Spring
The tension spring should be working properly, stopping the tension gradually coming off. Without the spring unnecessary tension is often used and accelerates the speed at which gear wears, requiring a major gear grinding job.
If a new spring is too tight, remove it and squeeze it up before refitting. This will allow it to retain tension without making it so tight that it makes changing cutters difficult.
Figure 6.6 Parts requiring periodic replacement
Fork Yoke Retaining Bar
This bar is designed to secure the fork yokes to the fork.
Tension Pin Retaining Spring
This simply holds the tension pin in place. The handpiece is unsafe to use without it in place as the pin could slip while changing cutters. Note: Absence of an effective tension spring will contribute to lockups.
Figure 6.7 Essential parts
It is dangerous to operate any handpiece without them.
Centre Post and Cup
With normal use the back of the post wears against the back of the bottom cup to form a smooth complementary pivot surface. Once this surface is created, it is most important that the post is not moved from its original working position.
The only time the post should be adjusted is when you are installing a new post and bottom cup. You would normally replace the centre post and bottom cup when you are setting up a new supply of cutters.
With the handpiece set up with a comb and half worn cutter the correct setting is when one third of the crank roller is visible above the fork body when you look down the barrel from the cutter end. On a new handpiece the centre post is normally correctly set but should be checked.
Once it is bedded into the cup the centre post SHOULD NOT be adjusted.
Worn post and cupDo not adjust post once it is wornFigure 6.8 New post and cup
The Comb Bed or Baseplate
The handpiece is a piece of precision machinery which can be easily distorted by rough treatment. Constant dropping on the floor, being kicked from the shearer's hand to smash against the wall or other maltreatment can bend the comb bed. This is a serious fault and is best fixed by sending the body of the handpiece to a suitably equipped engineer or agent who specialises in handpiece repairs.
A correctly aligned bed will be parallel to the screw bushing and at 90 degrees to the tension bushing.
Comb bed and tension bushing should be at right angles. Comb bed and screw bushing should be parallel.
Figure 6.9
If the comb bed is damaged, it must be repaired by a qualified shearing engineer.
6.1.1.5 Safety Tips
Do not operate the handpiece with badly worn fork yoke pins or when the fork yokes are sloppy inside the fork sleeves.
Do not start the handpiece without checking that:
- The comb screws are firmly tightened (note: excessive tightening will eventually strip threads in the handpiece body).
- The fork yoke pins are securely located in the cutter holes.
- The correct starting tension is applied. Using the thumb on the back cogs, move the cutter across the surface of the comb. A safe
starting tension will leave a good impression of the cogs on your thumb.
6.1.1.6 The Spline Drive/Pin Option
The traditional connection of the handpiece onto the down tube has been a pin drive. Another option which is becoming popular with some shearers is a spline drive.
This has an important safety benefit if the shearer hits an ear tag, piece of wire or the handpiece locks up for some other reason.
When operating with a spline drive, the handpiece usually unlocks from the gut before any serious damage occurs. With a pin drive, a lock-up will normally result in expensive breakages and possible loss of work through injury.
Many machines are not fitted with spline drives. Safety conscious shearers can overcome this by carrying their own appropriate short gut and fitting it into the machine before they start. Don't forget to retrieve it at the end of the job though!
6.1.1.7 Dressing a New Comb
Dressing a comb should always be done in good light and involves shaping the teeth to the ideal profile. This should be done before the comb is ground and requires three stages.
1. Shape the bevel to the desired profile using a piece of fine emery working from the back of the comb over to the cutting face aiming at a high rounded point. There are three common faults which should be avoided:
(A) Too round: will not enter the wool properly and tends to ride out of the wool.
(B) Dropped point: with a tooth of this shape skin cuts will occur.
(C) Squared off points: will not enter the wool easily and skin cuts will occur.
(D) The correct shape: the most important part of dressing a comb is the finish. All teeth must be dressed to the same shape and
must also follow an even concave.
2. When the bevels are finished, the next step is to fine the bottom edge of the bevel (the edge that runs along the skin) down to approximately the thickness of the edge of a postcard.
Good fine teeth mean better combing. Using a fine wedged slip stone, emery or a tapered spinning disc grinder called a bright boy, start from the back of the tooth and work around to the point, taking care not to alter the point which has just been formed nor to go too far and damage the cutting edge of the comb. DO NOT OVERTHIN.
As illustrated, if the teeth have not been thinned, they will ride off the skin causing second cuts (A);
The comb best suited to quality work is where the tips have a fine white line around the end of the tooth (B);
Over thinning will cause skin cuts (C).
3. To get a smooth finish, use 1200 grade wet and dry sandpaper then check bevel fineness to make sure all the teeth are of the same thickness.
Polish the teeth by rubbing on a leather strap, an old rubber tyre or a machine buffer. Use polishing compound for a good shiny finish. Polishing combs helps to stop the greasy building up and allows for smoother entry and running.
When you've completed dressing and polishing combs grind them ready for shearing.
Figure 6.10 Common Faults
Figure 6.11 Thinning the teeth
Figure 6.12 Comb Tip
Dressing a Worn Comb
When combs are ground down so that the scallop grinds out and they become too sharp to use, repeat the process for dressing a new comb.
Each time the comb grinds out to a sharp tip, redressing is required. The teeth get shorter and slightly rounder each time. Note: Be careful not to sand along cutting edges.
6.1.1.8 Grinding
Grinding is an extremely important part of shearing. It requires a high degree of precision and care. Shearers often blame their handpieces, the sheep or themselves for their difficulties. Often poor grinding technique or faulty machinery can be the cause.
Safety
- The grinder should be placed away from doorways and steps.
- It should be in a well-lit area with easy access for grinding.
- Never leave the grinder running unattended.
- Check the pins on the pendulum for length.
- Guards must be fitted to the grinder.
- The use of safety glasses is essential. (Carry a pair in your tool kit).
- Always check nuts are tight before turning grinder on.
Note: A grinder can be lethal. Do not rush when grinding, use common sense and safety equipment - for your own sake and the sake of others in the shed.
Top magnetic bar is slightly shorter than lower pressure bar so that the heel of the comb or cutter always touches the disc first.
Figure 6.13 The PendulumBottom view of the pendulum bar showing corners ground off. This will prevent an accurate grind.
Figure 6.14 A damaged holder will not grind properly
The Pendulum
The exclusive use of a good pendulum on a correctly set grinder will ensure reliable and efficient grinding at all times.
Pendulum Maintenance
The bottom bar of the pendulum applies pressure to the comb or cutter during grinding and it is essential that it is true. If the bar has the corners ground off, it will not give an accurate grind.
The recommended setting between the pressure bar and pins is 4 mm; a closer setting will heel grind; a wider pin setting will tip grind.
Make sure that the pins are long enough so that they maintain a hold on the comb or cutter.
- When not in use store so that the pendulum rod does not bend.
- Use a metal strip on the magnetic bar to retain magnetism.
Heel Grinding
Heel grinding results from use of pendulums where the pin settings are closer than the recommended 4 mm. To avoid tip grinding a small bevel may be removed from the heel of the comb.
Excessive heel grinding is not recommended because it:
- Prevents sufficient grinding pressure being applied to the tips of the comb to sharpen cutting surfaces properly.
- Creates excessive flexibility in the heel of the comb.
- Affects the contact of the comb screws on the comb.
The Hollow Grind
The face of the grinder disc is shaped to give a very slight hollow grind between heel and tip of combs and cutters. This is essential to bring the cutting edges of the comb and cutter together properly under pressure.
Grinder Setting
The height setting of the pendulum is very important to produce the hollow grind on the face of the comb or cutter. When the pendulum rod is handing straight, a vertical flow of sparks from the tips will indicate the correct settings.
Using the hook to suspend the pendulum, the heel of the comb or cutter should touch the disc just before the tips. With the pendulum hanging straight, the magnetic bar should hand 25 mm from the outer edge of the disc.
The Disc has a half degree fall from centre to edge.
This produces a hollow grind in the gear from heel to toe.
Figure 6.15 Grinding disc6.1.1.9 Grinding Procedure
Combs:
Combs should be ground on the coarse paper (40 grade) with the bottom tooth of the comb towards the outside of the disc. After ensuring the pins of the pendulum are in the holes of the comb, put the comb to the disc. Using a firm even pressure move the comb five or six times (six to eight seconds) across the paper, making sure it does not run off the edge or into the centre of the disc. Before removing the comb, hold it still with an even pressure for 2-3 seconds with the pendulum rod straight.
- Ensure that the sparks are even right across the comb.
- Remember too much pressure overheats and distorts the comb.
After grinding, check combs by looking across the teeth from side to side in good light.
The HEIGHT SETTING of the pendulum is therefore MOST IMPORTANT.
A vertical glow of sparks indicates the ideal setting.
Pendulum rod must hand parallel to disc with the heel of the comb or cutter touching first. Edge of magnetic head should hang 25 mm from edge of disc. Pins must swing just under the centre of the shaft for cutters and to the bottom of the shaft for combs.
Figure 6.16
Combs: Cross section of one tooth, shows original sharp edge rounded with use.
Partially ground edges show up as white hairlines on the edges of the teeth.
Cutters:
Follow the same procedure as with combs using an even lighter pressure and reduce to two to four passes (3-4 seconds) across fine paper (80 grade).
Cutters should be ground evenly over the whole surface with no dull tips. If there are any faults repeat procedure.
Should be ground evenly over the whole surface with no dull tips or white hair lines on the edges of the teeth.
Figure 6.19 Cutters
Check that cutters are grinding down evenly on both sides. Also ensure that each cutter is wearing at the same rate. Rotating on a wire or cutter holder will help. The handpiece will work better and last longer if the cutters wear down at an even rate. For a full time professional shearer a string of 50 cutters is recommended.
If there are any faults after the check repeat the grinding procedure and recheck.
6.1.1.10 Grinding Equipment
Setting Papers:
Always store papers in dry conditions. Ensure that the disc is clean, free from old glue and dry. Place new paper on clamp. Spread glue onto the disc evenly and sparingly, then clamp the paper firmly but without excessive pressure. A thin flat sheet of cardboard between the emery and the clamp will reduce the crushing of the emery grit.
Care of Papers:
Do not grind first thing in the morning or when the atmosphere is damp. When the papers are partly worn they can be revived by using a rubber cleaning stick and a light stroke with a carborundum stone or wire brush. Light, even grinding will also make papers last longer.
Grinder Maintenance:
Although discs are made of cast steel, they can be distorted by rough treatment or wear and tear.
- When not in use for long periods store discs on the clamps.
- Check that the back of the disc and the area where it connects to the grinder are clean when mounting discs.
- The centre of the paper should be cut out and any excessive glue cleaned away.
- Always use washers when setting paper and mounting discs on grinder.
- These machines are for sharpening shearing gear and should not be used as bench grinders.
- Discs in need of repair can be refaced and rebalanced by engineers specialising in shearing equipment.
Note: For best results, use your own grinder all the time or carry your own discs from shed to shed. Always use your own pendulum.
Took me 2 naps but got there in the end!?? Good info all the same ? Now what was the first thing?????
exmoor dave
Member
- Location
- exmoor, uk
Read a good article about that period of shearing history.
I think there was a quote in there from aussie shearers at the time..... "bloody kiwis....and their bloody wide combs"
Unbelievable that Australia persisted with narrows so long after wide combs were the norm in NZ.
I believe shearing was very heavily unionized in Oz too?
Weren't some places still using hand shears for a long time as well?
I did a cull ewe that had struck in the middle of her back in the field with a pair a few days ago (meant to be going Tuesday FFS) f**k that for a job I'd have almost been faster taking her home and doing her with a machine.
Driven clippers would get the maggots out better as well.
Theres still blade shearing competition class
spin cycle
Member
- Location
- north norfolk
what da y'mean....i fekkin wrote it
I see,
btw......The bit at the end
'Always use your own pendulum' was that some sort of euphemism and aimed at @Nithsdale Farmer
JD-Kid
Member
- Location
- Akaroa.. New Zealand
HAHAHA. it's more. every thing is the same. should use own grinder feet in the same place each time etc etc. so always. trying to get the same grind on gearI see,
......The bit at the end
'Always use your own pendulum' was that some sort of euphemism and aimed at @Nithsdale Farmer
JD-Kid
Member
- Location
- Akaroa.. New Zealand
know a guy in NZ brought in narrow gear to shear merinos years ago the shearers. could not use it very well once yer get use to wider gear. yer never realy go back
yep the union is quite strong in some states of aussie not sure if it's still as strong as it used to be alot of unions were making it harder for guys keen to get on and get the job done
Wide Comb dispute - Wikipedia
- Location
- Dumfries & Galloway
I see,
......The bit at the end
'Always use your own pendulum' was that some sort of euphemism and aimed at @Nithsdale Farmer
Well, you can only grind with the pendulum you've got
Tbh My grinding isn't consistent enough and I'm trying to improve it , thought it might be to do with having an old lister belt driven bit smaller diameter 14 inch wheel grinder, but its probably more to do with inexperience or not getting the pendulum position quite right on all the different types of gear weve got , going to stick with only one type of comb and one type of cutter in the future .
Trouble is with my old grinder , you got only one disc on at a time, hes single sided, so got to take off from the spindle swap between the disc for
combs and cutters one, apart from that hes fine , cant beat grinding your own gear.
I did do the wool board grinding session years ago, but that s all learnt and forgotten by now
- Location
- Dumfries & Galloway
Tbh My grinding isn't consistent enough and I'm trying to improve it , thought it might be to do with having an old lister belt driven bit smaller diameter 14 inch wheel grinder, but its probably more to do with inexperience or not getting the pendulum position quite right on all the different types of gear weve got , going to stick with only one type of comb and one type of cutter in the future .
Trouble is with my old grinder , you got only one disc on at a time, hes single sided, so got to take off from the spindle swap between the disc for
combs and cutters one, apart from that hes fine , cant beat grinding your own gear.
I did do the wool board grinding session years ago, but that s all learnt and forgotten by now
Put a 60 grit on and do both Combs and cutters on the same paper, instead of 40 and 80 grits...
Combs won't make much odds, cutters might if they're markedly different in shape/style.
It'll be your grind is most 'wrong', make sure you're applying nice even pressure across the whole swipe left and right, as JD says make sure your elbow and shoulder are directly behind the pendulum and now pushed away to either side...
Then it's just a case of taking a little more metal off of each cutter and comb (grind for a longer time), it could simply be a case you're not taking the blunt edge completely off the gear so it's not fully sharp