FAULTS.3

Question 1

RIBBON IS CURVED, CROOKED, OR UNEVEN INSTEAD OF STRAIGHT

1. Blunt of dull spot on the knife, producing an irregular knife edge
   - remedy:
2. Edges of the block are not parallel but round or wedge shape
   - remedy:
3. Knife is not parallel to the block
   - remedy:
4. Paraffin is impure
   - remedy:

Answer 1

1. Blunt of dull spot on the knife, producing an irregular knife edge
   - remedy: Adjust the knife so that knife edge will present uniformly sharp edge
2. Edges of the block are not parallel but round or wedge shape
   - remedy: re trim the block
3. Knife is not parallel to the block
   - remedy: re adjust the knife and block
4. Paraffin is impure
   - remedy: repeat impregnation using pure wax

Question 2

SECTIONS ARE COMPRESSED, WRINKLED, OR JAMMED

1. Knife is blunt or dull
   - remedy:
2. Paraffin block is warm & soft
   - remedy:
3. Knife edge is coated with paraffin
   - remedy:
4. Sections are too thin
   - remedy:
5. Microtome set screw is loose
   - remedy:
6. Tilt of knife is too vertical
   - remedy:

Answer 2

1. Knife is blunt or dull
   - remedy: resharpen knife
2. Paraffin block is warm & soft
   - remedy: cool the block on ice water until firm
3. Knife edge is coated with paraffin
   - remedy: clean the knife edge
4. Sections are too thin
   - remedy: readjust the thickness of section
5. Microtome set screw is loose
   - remedy: tighten the screw
6. Tilt of knife is too vertical
   - remedy: reduce the tilt

Question 3

SECTIONS ARE SQUASHED (WIDTH OF EACH SECTION IS LESS THAN THAT OF BLOCK)

1. Reason:
2. Remedy: Re sharpen, using a ____ or ______

Answer 3

1. Reason: Bevel of knife is lost due to incorrect sharpening
2. Remedy: Re sharpen, using a knife back or automatic knife sharpener

Question 4

A HOLE IS FORMED IN THE SECTION

1. Bubble or dirt formed in embedding medium
   - remedy:
2. Hard spot in tissue due to calcium
   - remedy: once embedded in paraffin wax, delcalcification is impractical; use a _____ w/ ______

Answer 4

1. Bubble or dirt formed in embedding medium
   - remedy: re embed in freshly filtered wax if necessary
2. Hard spot in tissue due to calcium
   - remedy: once embedded in paraffin wax, delcalcification is impractical; use a BASE-SLEDGE MICROTOME w/ WEDGE KNIFE

Question 5

SECTIONS OF UNEQUAL THICKNESS ARE PRODUCED

1. Tilt of knife is too gray or bevel is not cleared, hence object is compressed against the knife edge
   - remedy:
2. Clamp set screw on knife or block holder is loose
   - remedy:
3. Blocks are too large:
   - remedy:
4. Blocks are too hard:
   - remedy:

Answer 5

1. Tilt of knife is too gray or bevel is not cleared, hence object is compressed against the knife edge
   - remedy: Reduce the tilt
2. Clamp set screw on knife or block holder is loose
   - remedy: tighten the screw
3. Blocks are too large:
   - remedy: cut blocks into smaller fragments
4. Blocks are too hard:
   - remedy: soften the blocks in detergent or phenol

Question 6

SECTIONS OF UNEQUAL THICKNESS ARE PRODUCED

1. Tilt of knife is too gray or bevel is not cleared, hence object is compressed against the knife edge
   - remedy:
2. Clamp set screw on knife or block holder is loose
   - remedy:
3. Blocks are too large:
   - remedy:
4. Blocks are too hard:
   - remedy:

Answer 6

1. Tilt of knife is too gray or bevel is not cleared, hence object is compressed against the knife edge
   - remedy: Reduce the tilt
2. Clamp set screw on knife or block holder is loose
   - remedy: tighten the screw
3. Blocks are too large:
   - remedy: cut blocks into smaller fragments
4. Blocks are too hard:
   - remedy: soften the blocks in detergent or phenol