K if Sh iK if Sh iKnife SharpeningKnife Sharpening

Sheldon Becker S Q fSouthern Qld Institute of TAFE

Poultry Processingy g

Using knives continuouslyUsing knives continuously relates up to 50% of injuries (lacerations or muscle strains)(lacerations or muscle strains)

Meat processing

In the red meat industry up to 68% of injuriesup to 68% of injuries

Of which 32% is cuts &Of which 32% is cuts &lacerations

Blunt KnivesBlunt Knives

- are frustrating to use- can lower the quality of the product- often the cause of accidentsoften the cause of accidents- can be responsible for Occupational O S d (OCC) t i j iOveruse Syndrome (OCC) type injuries

Who likes sharpening knives?

Blunt knives can lead to unsafe practicesPoor 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 incorrectchecking steeling action, grip on knife, and steel is incorrect

Repetition work – Continuously making additional cuts or doing same task

How have most people here How have most people here learnt how to sharpen a knife?learnt how to sharpen a knife?

Maybe from a fellow workerMaybe from a fellow workerMaybe from a fellow workerMaybe from a fellow worker

Some workplaces have a mentor/ trainerSome workplaces have a mentor/ trainer

Watching others sharpen their knivesWatching others sharpen their knives

Taught themselves through trail and errorTaught themselves through trail and errorTaught themselves through trail and errorTaught themselves through trail and error

Benefits of Knife Sharpening trainingBenefits of Knife Sharpening trainingg gg gWould see a reduction in:

Knife related injuriesT d itiTendonitisCarpel TunnelpTennis ElbowM l k l t l i j iMusculoskeletal injuriesTime off workTime off workImproved productionJob becomes easier

TrainingTrainingWho 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

Key points to lessen knife i j iinjuries

Warm up before startingWarm up before starting– Follow recommended stretching practices.

Use a good shape blade– Choose the correct knife for the job.j

Work with a rhythmMinimise your blows or cuts and work– Minimise your blows or cuts and work

more efficientlyT k b kTake breaks

– Do not work through breaks- Take breaks as required

Identifying the symptoms of l k l t l i j imusculoskeletal injuries

Muscle discomfortMuscle discomfortFatigueAches and painsSorenessSorenessHot feelingsCold feelingsMuscle tightnessMuscle tightnessNumbness tinglingMuscle weakness

Occupational Overuse Syndrome (OOS)

OOS usually develops over a period of timeperiod of time.

Caused or aggravated by :-- sustained or constrained postures - repetitive movementsepet t e o e e ts

One explanations for OOS is that it isOne explanations for OOS is that it is caused by the muscles being held too tight for long periods of timefor long periods of time

NZ Grip force studyNZ Grip force studyIndependent study foundIndependent study found

20% of the process workers have a reasonably good knifereasonably good knife

40% had an average knife

40% had a knife that was insufficient for the task

NZ Grip force studyNZ Grip force study

Study also found the tighter the grip on theStudy also found the tighter the grip on theknife the less blood flow in the hand and arm.

The size of the hand holding the knife is also ga factor on grip force.

The knife lengthThe knife lengthThe length and weight test used to determine grip force

Place a 0.5 kg weight 13 cm, 15 cm, 17 cm g g , ,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.

Cutting ForceCutting ForceA sharp knife requires 30% less force to cut than an average knifeA h k if l bl t k t b f d 30%A sharp knife also enables a task to be performed 30% faster, and requires 30% less grip forceA processing room with consistently sharp knives producedA processing room with consistently sharp knives produced a 1 to 3 % greater yield than the same room with normal levels of sharpnesse e s o s a p essBy testing a knife we can now tell how much cutting force is required to cut with that knifeqWe can now calculate how much cutting force a worker is using over a days work

Sharpness TesterSharpness Tester

Score

ExamplepA worker boning forequarters all day would use approx 6400 cutting strokes a dayapprox 6400 cutting strokes a day

A sharp knife has a cutting force of 1.1kg perA 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 tonknife, we end up with a daily force of 96 ton

This equates to 88 6 tons more cutting forceThis equates to 88.6 tons more cutting force than a sharp knife

NZ experiencep

Photo courtesy of Anago Ltd

Equipment use to sharpenEquipment 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 facilitiesWashing & sterilising facilities

Safety Equipment usedy q pwhen sharpening a knife

Cut resistant Safety glasses

Choose a knife suitable for the task.

Skinning KnifeSkinning Knife

C d b i k ifCurved boning knife

Straight boning knife

Sli i k ifSlicing knife

Knife Shapes

FlatConvex Hollow Concave

Equipment used to shape/sharpenknives

Sandstone wheel Belt Grinders

Grinding the knifeGrinding the knife

Sharpening the knifep g

Sharpening or honing stone are used to

establish a sharp edge on a knife.

Methods used to sharpen a knife

Sharpening stone SetterSharpening stone Setter

IssuesEvenly grinding of knives to the correct shape

b th id- both sides- from tip to heel

Evenly sharpening knives (correct edge)Evenly sharpening knives (correct edge)- both sides

f ti t h l- from tip to heel

Evenly & effectively steeling knives

“It all about the correct angles”

Hollow GrindersHollow Grinders

Used by authorised personal only

Knife setterKnife setter

Knife settersKnife setters

Creating a featherCreating a feather

Work from tip to heel, then heel to tipStand on handle side of knife p , pto develop a feather.Turn knife over & repeat process

when stoning. Place thumband forefinger on stoning rod &other hand on stoning bar.

Removing featherRemoving feather

Start by placing heel of stone on theStart by placing heel of stone on theknife tip. Pull the stoning rodstraight back over the cutting edgeoverlapping the stone on each stroke

Run the knife through a plastic block(Feathering Block)

overlapping the stone on each stroke.Turn knife over & repeat

Finishing strokesFinishing strokes

Place the heel of the stone on the tipPlace the heel of the stone on the tipof the knife and pull stoning rod backtoward the knife handle 6 times.Turn knife over and repeat processTurn knife over and repeat process

Steeling a knifeSteeling a knife

To remove any burrs from the edge

To straighten (centre) the edgeTo straighten (centre) the edge

Types of SteelsTypes of Steels

Holding a knifeHolding a knife

Make sure the knife butt Make sure you tuck The knife should be in asits in the groove of yourthumb and forefinger palm

your little finger on the side of the handle

The knife should be in astraight line with your arm

Steeling a knifeSteeling a knife

Hold steel as above with the thumb tucked behind steel

Check arm, steel and knife are square and in line.Knife handle centre of wrist

Storing KnivesStoring Knives

Knives must be stored in the pouch when not in use

Testing biteTesting biteTesting biteTesting bite

Bite Stick Stick

Bites left Bites right

Bite Stick Stick

Both sides of the knife are sharp

Testing biteTesting biteTesting biteTesting bite

Bite Stick Stick

Slides rightBites left

Bite Stick Stick

Bite left only knife is turned to the leftte e t o y e s tu ed to t e e tSteel left side of knife the bite side.

Testing biteTesting biteTesting biteTesting bite

Bite Stick Stick

Slides left Bites right

Bite Stick Stick

Bite right only knife is turned to the rightBite right only knife is turned to the rightSteel right side of knife the bite side

Testing biteTesting biteTesting biteTesting bite

Bite Stick Stick

Slides left Slides right

Bite Stick Stick

Slides both ways there is no bite knife willSlides both ways, there is no bite, knife willneed to be steeled again or sharpened

Safety Equipment y q pwhen using a knife

Cut resistant

MeshMesh

Safety ApronsSafety Aprons

Now That’s A KnifeNow That s A Knife

AcknowledgementsAcknowledgementsAcknowledgementsAcknowledgements

Southern Southern QQld Institute of TAFE would like to ld Institute of TAFE would like to acknowledge contributions by:acknowledge contributions by:--g yg y

Bi B Skill T i i LtdBi B Skill T i i LtdBig Bay Skills Training LtdBig Bay Skills Training Ltd

Argus Argus RealcoldRealcold LimitedLimited

TeysTeys Bros Pty LtdBros Pty LtdTeysTeys Bros Pty LtdBros Pty Ltd

??Question?Question?ThankyouThankyouT a yT a y