HONING AND STROPPING- LABORATORY

BEVEL

cutting facet, found on the tapered edge of all knives.

BEVEL ANGLE

the angle formed between the cutting edge

27 to 32 Degrees

BEVEL ANGLE

KNIFE BACK

maintains the bevel angle

CUTTING ANGLE

optimal angle of 15 degrees.

CUTTING ANGLE

Less distortion and maximum penetration

CLEARANCE ANGLE

0-15 Degrees

CLEARANCE ANGLE

Angle formed between the surface of the block and the cutting edge of the knife

HONING

HARD Knife Sharpening

HONING

• Removes gross nicks on the knife edge (Coarse honing)

• Removes blemishes.

HONING

Grinding the cutting edge of the knife on a stone

BELGIUM YELLOW

manual sharpening. Best honing result

ARKANSAS

more polishing effect compared to Belgium Yellow

FINE CARBORUNDUM

much coarser than others. Used for badly nicked knives.

LUBRICANTS FOR HONING

Soapy water, mineral oil, Clove oil, Xylene or Liquid Paraffin

HONING MOVEMENT

EDGE FIRST

HONING MOVEMENT

HEEL TO TOE DIRECTION

20-30 strokes

HONING- NUMBER OF STROKES

10-20 strokes

HONING- In Minot or Plane Wedge Knife

STROPPING

removes the burr of the knife formed during honing

STROPPING

Polishing and sharpening of the cutting edge

Paddle strop

is made of a fine horse leather.

STROPPING MOVEMENT

EDGE LAST

STROPPING MOVEMENT

TOE TO HEEL DIRECTION

knife is turned around at the end of each stroke

STROPPING – In Minot or Plane Wedge Knife

the concave surface is stropped

STROPPING – For Plane Concave Knives

Frozen Sections

for rapid diagnosis during surgery, research enzyme histochemistry, lipids and carbohydrates studies

Frozen Sections

For immunofluorescent and immunocytochemical staining.

Frozen Sections

For special silver staining particularly in neuropathology

COLD KNIFE METHOD

Use of conventional freezing microtome with Carbon Dioxide

3-5 mm

COLD KNIFE METHOD- Tissue block thickness is

Dew Line

point where the tissues may be cut at 10 um.

-40 Celsius to -60 Celsius

TEMPERATURES FOR OPTIMUM OPERATION (KNIFE)

-5 Celsius to -10 Celsius

TEMPERATURES FOR OPTIMUM OPERATION (TISSUE)

0 Celsius to -10 Celsius

TEMPERATURES FOR OPTIMUM OPERATION (ENVIRONMENT)

CRYOSTAT METHOD

Near – 20 Celsius (Microtome Knife, Specimen and the Atmosphere)

-18 to -20 Celsius

CRYOSTAT METHOD- Optimum working temperature is

Common freezing agents

Liquid Nitrogen, Isopentane cooled by

Liquid Nitrogen, Carbon Dioxide Gas and Aerosol Sprays

LIQUID NITROGEN

Histochemistry, Intra-operative diagnosis, most rapid.

LIQUID NITROGEN

Main disadvantage is soft tissues is liable to crack due to rapid expansion. (Ice crystallization inside the tissue)

ISOPENTANE

Liquid at room temperature

ISOPENTANE

Tissue is frozen, affixed on a cork disc, aluminum foil or cryostat chuck

AEROSOL SPRAY

For small tissues except the muscle

AEROSOL SPRAY

Fluorinated Hydrocarbons (Cryokwik) – rapid freezing of any tissues

CARBON DIOXIDE GAS

At – 50 Celsius

-5 TO -15 Celsius

Brain, lymph nodes, liver, spleen, uterine curetting and soft cellular tumor

-15 TO -25 Celsius

Non-fatty breast tissue, ovary, prostate, tongue and GI tract

-35 Celsius

Fatty Breast and omental tissue