CONTROLLED COPY
Centre for Biological Engineering
Standard Operating Procedure
SOP194
Title: Use and maintenance of Leica RM2125 RTS rotary microtome.
Location:
H27
Version 001
Effective Date: 24.05.2021
Review 24.05.2023
Written by: Sotiria Toumpaniari
Reviewed by:
Approved by: C.Kavanagh
Page 5 of 11
Note:
The user can switch the specimen retraction ON or OFF.
(ii) To do so, use an Allen key with handle, No. 4 (included in the delivery package) and turn the screw
depicted in the detail picture (Fig. 13a) so that the red dot indicates "
OFF
" = retraction is disabled. Red
dot on "
ON
" means = retraction is switched on.
(iii) Important if retraction is enabled:
The specimen must NOT be oriented or approached in the retraction phase (if the black dot on the
handwheel is visible – see enlarged detail Fig. 13 – you are in the sectioning phase)! The previously
retracted specimen will advance by the retraction value PLUS the selected section thickness before the
next section.
There is a danger of the specimen and knife being damaged by a section that is too thick.
The same applies to the "rocking mode", during which the specimen is trimmed by rocking motion (no
complete rotation of the handwheel).
Carry out "rocking mode" ONLY in the sectioning phase – NEVER in the retraction phase!
5.3.5. Orienting the specimen
The specimen orientation allows for simple position correction of the specimen surface when the
specimen is clamped into place.
1. Run the specimen to the rear end position by turning the coarse feed wheel.
2. Loosen the clamping lever in front on the microtome base plate and slide the knife holder base with
knife holder until it is almost in front of the specimen.
Note:
Specimen blocks must NOT be oriented during the retraction phase!
If a block is oriented during retraction, the block will advance by the retraction value PLUS the selected
section thickness before the next section.
This may cause damage to both specimen and knife!
3. Move the specimen holder fixture to the upper end position by turning the handwheel and engage
the handwheel lock.
4. To release the clamp, turn the eccentric lever (12) counterclockwise.
5. Turn setscrew (14) to orient the specimen in north-south direction. Turn setscrew (13) to orient the
specimen in east-west direction.
6. To lock the current orientation, turn the eccentric lever (12) clockwise.
