Rotary Microtome HM 325
MICROM International GmbH
Robert-Bosch-Str. 49
D- 69190 Walldorf
387821 - English
During practical work the angle of inclination is our
so-called clearance angle, i.e. the angle between
lower facet surface and block surface. The optimal
inclination slightly differs for each knife, as the
wedge angles as well as especially the facet
angles on the individual knives are not absolutely
identical.
The knife must never be placed too flat. This way,
the blade does not cut into the block at all. Only
the rear side slides over the sectioning surface
(see opposite figure).
An inclination, which is too steep, is also
unfavorable as the knife might vibrate too much
while sectioning. The so-called "chatters" appear
on the block surface as well as on the sections.
These chatters are parallel stripes in relation to
the knife edge having negative effects on the
microscopical evaluation of sections.
Between these two limit cases, the correct knife
inclination must be determined. A clearance angle
between facet angle and block surface of approx.
5° is normal.
Caution:
Different microtome producer use
different scalings for their clearance
angle adjustment, resulting from
different calculation bases. The clearance angle
might refer to the facet surface or to the angle
between knife main surface and block surface. As
the facet has a divergence from the knife main
surface of approx. 5°, the difference is approx. 5°.
Set the correct angle on MICROM instruments at
10°.
Fig. 28
Fig. 29
Fig. 30