Scissors Anatomy

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Scissors Anatomy
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Ratio of Transmission of Torque
Leverage
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Are your scissors in good condition?
It seems cut but actuary damage them
Not sharp and also loose tension
Perfect condition Healthy Hair
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The Edge

• Convex Edge ( very thin sharp )
• Concave hollow along the edge.
• Bowed bowing each other.
• Twisted twisted like a propeller.
• All three of these components of scissor are
  important.

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• Convex Blade "Convex blades" with extremely
  sharp-angled edges are expertly sharpened by
  craftsmen grinding technique, leaving each blade
  with a combination of smoothness, precision and
  sharpness.
• Beveled Blade A bevel edge is harsher when
  cutting hair and probably won't be enjoyed as
  much. Most stylist prefer the convex edge because
  it is smoother.

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Character of angle of edge
18 30 degree Very sharp and smooth Sharpness
does not last too long. Edge R directly
influence to cutting. R is radius of
edge line.
40 - 60 degree Cut feeling is heavy and
firm. Sharpness lasts longer. Edge R will not
directly influence to cutting.
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Hone line

• Sharp edge would rub themselves dull
• on the edge.
• The hone line is the thin flat line that you
  see on the hollow side of the edge. It runs from
  the tip of the scissor to the back.
• This gives the scissor a smooth and quiet run.

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Bowed
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Bowed

• Strong bowed is good for slow movement cut
• Strong bowed is suitable for hard hair as well as
  cutting more hair in one section. Bunch of hair
• Easy bowed is good for faster movement cut.
• Easy bowed doesnt make enough contact pressure.
  
• Clearance of 0.005mm (approx)

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Point of Action

• Since both blades are bowing to each other, point
  of action must be exactly the same point on
  their shear line.
• When this balance is changed, a point of action
  will be changed. Deep bowed blade makes both
  shear lines damaged.

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Shear Line

• Straight line
• You may feel harder and feel like cut off.
• Cut result in a straight cut line.
• Ratio of cut is higher.
• Yanagi-ba can help to create sensitive cut line.
• Shear line is almost same as a part of 800mm
  radius.
• Sasa-ba is suitable for slide cut and it creates
  softer cut line. Wider blade and shear line
  almost same as a part of 600mm radius.

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Convex Shear Line is not straight. Most shapes
are a part of 800 millimeter radius.
Some bevel edge has complex edge R
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Peak

• Peak of Convex Edge has Elasticity according to
  its shape. It creates contact pressure.
• Sword Edge has a center of balance on the middle
  of blade. It transmits hand power to the edge
  more powerful than the other blades.

Lateral pressure Pressure to the side direction
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Short Scissors

• Advantage
• Good for stroke and slide cut.
• The weight is suitable for those who require
  stability.
• Light scissors are usually preferred.
• Disadvantage
• Cutting Feels more direct than long one.
• Slide the hair toward the tip of the scissors
  easily.

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Long Scissors

• Advantage
• Good for straight cut line.
• Weight would be absorbed a shock of cut.
  (stability).
• Disadvantage
• Angle of Bite is smaller
• Contact Pressure (Power of Cut) is going to
  decrease by progressing at top.
• Lateral pressure may cause of not cut.

Pressure to the side direction
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Why going to dull?

• If you keep using them for 3 to 4 month without
  sharpening, radius of edge line are increased or
  become serrated.
• Dropping, cutting more than scissors capability,
  operating with incorrect tension
• and other bad affect such as water, dirt,
  chemical, and etc make scissors unbalanced.

Corrosion
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Never complete a cut if the section of hair gives
you resistance. This is the most important rule
in caring for shears, and it is also the most
common way stylists damage their shears. If you
struggle while cutting hair, the shears are too
light for the task, and forces to the blades can
severely damage edges. In this case, cut smaller
sections instead.
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• Destroyed Hone Line with wheel type of sharpening
  machine.
• You should consider purchasing a new pair.
• (Up) Hardened chemical makes greatly reduce of
  Cut.
• This is Shame.

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• Wipe from both side 3 5 times each.
• Burr ( fine dust of metal ), cuticle, hair oil
  and more stuff are mixed up and sticking on the
  edge of the blade.

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Galling