23
5.4 Evaluation of the knife edge
After making a pair of knives, evaluation of the quality can be carried out with the
Ultramicrotome (Leica Ultracut UCT / R / S).
Using the backlight illumination and setting the clearance angle to maximum a fine white
line can be seen
(Fig.28)
.
The image of the line indicates the quality of the knife edge, which must be straight,
free of any dirt such dust, grease and finger prints and free of glass splinters.
The top light of the ultramicrotome can also be used for checking knife quality
(Fig.29).
An example of a knife which should not be used is shown in
Fig.30
.
This has been picked up incorrectly leaving a finger print over the knife edge.
In
Fig.31
a pair of knives is shown, broken and placed side by side
according to chapter
5.3
.
The detail
(Fig. 32)
shows the knife shoulder of both knives
The right hand knife edge was opposite the left hand knife shoulder during breaking
and the left hand knife edge was opposite the right hand knife shoulder.
The knife edge opposite a small knife shoulder (< 0.2mm) has a knife angle
very close to 45°, as recommended for cryo-ultramicrotomy
(Fig.32a)
.
(
Griffiths et al. 1983: Tokuyasu 1986
).
For resin sectioning a larger knife shoulder (approx. 1mm) is recommended.
Fig.32a
Note: the sharpest knife edge is the one
opposite the smaller knife shoulder!
Knife angle close to 45°
Summary of Contents for EM KMR2
Page 2: ...2 ...
Page 4: ...4 ...
Page 8: ...8 Fig 4 Scoring angle Real knife angle Fig 5 Stress line ...
Page 10: ...10 Fig 6 Fig 7 Fig 8 Side view Fig 8 ...
Page 12: ...12 Fig 9 1 2 3 4 5 6 7 8 9 10 11 ...
Page 14: ...14 Fig 10 Moveable stop at position 1 Fig 11 Fig 11a ...
Page 16: ...16 Fig 12 Fig 13 Fig 14 Fig 15 Fig 16 Fig 17 Moveable stop at position 2 ...
Page 20: ...20 Fig 24 Fig 25 Fig 26 Fig 27 ...
Page 22: ...22 Fig 28 Fig 29 Fig 30 Fig 31 Right hand knife Left hand knife Fig 32 ...
Page 26: ...26 Fig 34 Fig 35 Fig 36 Sliding surfaces ...
Page 28: ...28 Fig 39 Fig 40 Fig 41 ...
Page 30: ...30 Fig 42 Fig 43 Fig 44 Fig 45 Hotplate Wax bath ...