1. Knife Sharpening
Sheldon Becker
Southern Qld Institute of TAFE

2. Poultry Processing Using knives continuously
relates up to 50% of injuries
(lacerations or muscle strains)

3. Meat processing In the red meat industry up to 68% of injuries
Of which 32% is cuts &
lacerations

4. Blunt Knives Who likes sharpening knives? - are frustrating to use
- can lower the quality of the product
- often the cause of accidents
- can be responsible for Occupational Overuse Syndrome (OCC) type injuries
Who likes sharpening knives?

5. Blunt knives can lead to unsafe practices
Poor running point – Running hand up blade
Pushing when blunt – Physically pushing and dragging the knife
Over stretching – Not maintaining balance properly, not keeping up
Violent or sudden movements – Stabbing or hacking at the product
Deterioration – Tiredness, hands and arms are can cramp up & get sore
Emotional and Physical well being – Facing another day with a blunt knife is not fun, social issues impacting on your work
Incorrect steeling practices – Back steeling, uneven angles, not checking steeling action, grip on knife, and steel is incorrect
Repetition work – Continuously making additional cuts or doing same task

6. How have most people here learnt how to sharpen a knife?
Maybe from a fellow worker
Some workplaces have a mentor/ trainer
Watching others sharpen their knives
Taught themselves through trail and error

7. Benefits of Knife Sharpening training
Would see a reduction in:
Knife related injuries
Tendonitis
Carpel Tunnel
Tennis Elbow
Musculoskeletal injuries
Time off work
Improved production
Job becomes easier

8. Training Who to start with: staff new to the plant or industry
all staff demonstrating poor technique
staff with high incidents of knife injuries
staff struggling with the job
staff open to change

9. Key points to lessen knife injuries
Warm up before starting
– Follow recommended stretching practices.
Use a good shape blade
– Choose the correct knife for the job.
Work with a rhythm
– Minimise your blows or cuts and work more efficiently
Take breaks
– Do not work through breaks
- Take breaks as required

10. Identifying the symptoms of musculoskeletal injuries
Muscle discomfort
Fatigue
Aches and pains
Soreness
Hot feelings
Cold feelings
Muscle tightness
Numbness tingling
Muscle weakness

11. Occupational Overuse Syndrome (OOS)
OOS usually develops over a
period of time.
Caused or aggravated by :-
- sustained or constrained postures - repetitive movements
One explanations for OOS is that it is caused by the muscles being held too tight for long periods of time

12. NZ Grip force study Independent study found
20% of the process workers have a reasonably good knife
40% had an average knife
40% had a knife that was insufficient for the task

13. NZ Grip force study Study also found the tighter the grip on the
knife the less blood flow in the hand and arm.
The size of the hand holding the knife is also a factor on grip force.

14. The knife length
The length and weight test used to determine grip force
Place a 0.5 kg weight 13 cm, 15 cm, 17 cm distances along the steel or bar.
The grip force has increased as the length of each knife increases.
Longer blades require a greater grip force than shorter blades.

15. Cutting Force
A sharp knife requires 30% less force to cut than an average knife
A sharp knife also enables a task to be performed 30% faster, and requires 30% less grip force
A processing room with consistently sharp knives produced a 1 to 3 % greater yield than the same room with normal levels of sharpness
By testing a knife we can now tell how much cutting force is required to cut with that knife
We can now calculate how much cutting force a worker is using over a days work

16. Sharpness Tester

17. Score

18. Example
A worker boning forequarters all day would use approx 6400 cutting strokes a day
A sharp knife has a cutting force of 1.1kg per cutting stroke
1.1kg x 6400 strokes = 7.40 tons of daily force
If we multiply 6400 strokes with a 15kg blunt knife, we end up with a daily force of 96 ton
This equates to 88.6 tons more cutting force than a sharp knife

19. NZ experience
Photo courtesy of Anago Ltd

20. Equipment use to sharpen and maintain knives
Knives and their correct storage equipment
PPE (cut resistant gloves, safety glasses)
Grinding wheels (grinders)
Sharpening stones
Steels
Washing & sterilising facilities

21. when sharpening a knife
Safety Equipment used
when sharpening a knife
Cut resistant
Safety glasses

22. Choose a knife suitable for the task.
Skinning Knife
Curved boning knife
Straight boning knife
Slicing knife

23. Knife Shapes
Convex
Flat
Hollow
Concave

24. Equipment used to shape/sharpen
knives
Sandstone wheel
Belt Grinders

25. Grinding the knife

26. Sharpening the knife Sharpening or honing stone are used to
establish a sharp edge on a knife.

27. Methods used to sharpen a knife
Sharpening stone
Setter

28. Issues Evenly grinding of knives to the correct shape - both sides
- from tip to heel
Evenly sharpening knives (correct edge)
Evenly & effectively steeling knives
“It all about the correct angles”

29. Hollow Grinders
Used by authorised personal only

30. Knife setter

31. Knife setters

32. Creating a feather Stand on handle side of knife
when stoning. Place thumb
and forefinger on stoning rod &
other hand on stoning bar.
Work from tip to heel, then heel to tip
to develop a feather.
Turn knife over & repeat process

33. Removing feather Start by placing heel of stone on the
knife tip. Pull the stoning rod
straight back over the cutting edge
overlapping the stone on each stroke.
Turn knife over & repeat
Run the knife through a plastic block
(Feathering Block)

34. Finishing strokes Place the heel of the stone on the tip
of the knife and pull stoning rod back
toward the knife handle 6 times.
Turn knife over and repeat process

35. Steeling a knife To remove any burrs from the edge
To straighten (centre) the edge

36. Types of Steels

37. Holding a knife Make sure the knife butt
sits in the groove of your
thumb and forefinger palm
Make sure you tuck your little finger on the side of the handle
The knife should be in a
straight line with your arm

38. Steeling a knife Check arm, steel and knife are square and in line.
Knife handle centre of wrist
Hold steel as above with the thumb tucked behind steel

39. Storing Knives
Knives must be stored in the pouch when not in use

40. Testing bite Bites left Bites right Bite Stick Stick
Both sides of the knife are sharp

41. Testing bite Bites left Slides right Bite Stick Stick
Bite left only knife is turned to the left
Steel left side of knife the bite side.

42. Testing bite Slides left Bites right Bite Stick Stick
Bite right only knife is turned to the right
Steel right side of knife the bite side

43. Testing bite Slides right Slides left Bite Stick Stick
Slides both ways, there is no bite, knife will
need to be steeled again or sharpened

44. Safety Equipment when using a knife
Cut resistant
Mesh

45. Safety Aprons

46. Now That’s A Knife

47. Acknowledgements
Southern Qld Institute of TAFE would like to acknowledge contributions by:-
Big Bay Skills Training Ltd
Argus Realcold Limited
Teys Bros Pty Ltd

48. Question?
Thankyou