Leica EM KMR2 User manual

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Leica EM KMR2Leica EM KMR2
Leica EM KMR2Leica EM KMR2
Leica EM KMR2
Operating ManualOperating Manual
Operating ManualOperating Manual
Operating Manual
Order Number 177032
Leica EM KMR2 - GA-E-06/03

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Table of contents
1. Safety instructions
2. Principles of knifemaking
2.1 The Balanced Break method
2.2 Scoring and breaking principles
2.3 The real knife angle
2.4 Length of useful edge
3. Unpacking and installation
3.1 Unpacking
3.2 Packing list
3.3 Installation
4. Description of the LEICA EM KMR2
5. Knifemaking
5.1 Hints
5.2 Making squares
5.3 Making knives from a square
5.4 Evaluation of the knife edge
6. Customised adjustments
6.1 Knife shoulder fine adjustment
7. Care and maintainance
7.1 Replacement of the scoring wheel
7.2 Adjusting the scoring pressure
8. Mounting troughs (‘Trufs’) onto the knife
9. Accessories and consumables
10. Technical specifications

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1. Safety instructions
Prior to the operation of the Leica EM KMR2 read the instruction manual carefully.
Always use safety goggles during operation to avoid eye injury.
Clean the instrument regularly with a brush to remove glass splinters.
Store broken knives safely in the knife boxes provided.
Do not leave knives laying around or on the Leica EM KMR 2.
Used knives should be put into a marked “sharps” box for safe disposal.
Symbols in this manual and their meaning
Warning:
take extra care.
Notes:
Important information for the user.

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Fig.1
Fig.2
Breaking pins
Fig.3
Knife edge
Counterpiece/
Knife shoulder
Counterpiece/
Knife shoulder
Knife edge
Fig.3a

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2. Principles of Knifemaking
2.1 The Balanced Break method (Fig.1)
In the balanced break method, an original Leica glass strip 400mm in length
(6.4, 8 or 10mm thick), is scored and broken into two equal halves, each 200mm long.
With an equal mass of glass on each side of the score the break is balanced and the
freshly fractured surfaces are plane.
By continuing to divide each piece produced into two equal halves, up to 16 squares
can be made.
All squares produced have straight sides and precise right angled corners
unlike squares produced from sequential breaking of a glass strip which have curved
surfaces.
2.2 Scoring and breaking principles
Producing good glass knives routinely depends on a supply of reproducible squares, an
accurately positioned score and controlled pressure precisely applied to make the break.
The LEICA EM KMR2 gives the user a choice of two different scores, each one factory set
to produce the optimum break.
The long score is used to break squares out of glass strips as well as to score squares to
break knives. As a general rule, the knife edge is straighter and the counterpiece (knife
shoulder) is small when the fracture occurs close to the corner.
The short score was suggested for cryo knives as the free break is longer resulting in the
sharpest, longest useable knife edge (Griffiths et al 1983: Tokuyasu 1986).
Each score is preset and equidistant from the corners of the square.
During the break the glass sits on two breaking pins and is also held from above by
two more pins (Fig.2).
Both lower pins are fixed and one of the upper pins is fixed too, the other can be moved up
and down by means of the breaking lever and actually initiates the breaking of the glass.
The break follows the score line as far as it goes and then a free break occurs. The
direction of this free break is determined by the mass of the glass on either side of the
break and the breaking forces.
The free break curves to the edge of the square resulting in one knife and one flat-edge
counterpiece (knife shoulder) opposite the knife edge Fig.3.
When the score runs centrally through a square a very small counterpice (< 0.2mm) is
obtained and the knife angle is very close to 45° (Fig.3a).
This is the optimal result for cryo knives. For resin sectioning we set the knife
shoulder a little larger (approx. 1mm), to produce a larger knife angle which is
more stable for resin sectioning.

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Fig.4
Scoring angle
Real knife angle
Fig.5
Stress line

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2.3 The real knife angle
When scoring the square all scores stop some distance from the corner.
When pressure is applied under the score, the fracture is initiated and is seen first as a
deepening of the score. The fracture extends towards the corners of the square
following the line of the score. Where the score ends and the break is ”free” the
fracture deviates from the line of the score to curve away from the corner, towards one
of the edges of the square.This results in the real included angle of the knife being
somewhat greater than the angle of scoring.
The real angle of the knife increases as the score is moved further from the diagonal.
This is when the knife shoulder becomes larger.
For example, when preparing knives from a square, the real angle of the knife is close to
45° when the knife shoulder is smaller then 0.2mm.
Increasing the height of the knife shoulder (> 0.2mm) results in an even larger
knife angle which can be over 55° (Fig. 4).
2.4 Length of useful edge
When a glass knife edge is examined under darkfield illumination using a stereo
microscope (or on LEICA Ultramicrotomes using the back light, chapter 5.4), it can be
seen that the central part is most useful for ultrathin sectioning. The right side of the edge
has visible marks (saw teeth) which reduce the quality of the knife, and the left corner is
also unsuitable for sectioning because of the stress line (Fig.5).
The useful knife edge starts where the stress line does not touch the edge until the part
where the stress marks (saw teeth) can be seen.
Note:
The useful knife edge is 30% longer on knives produced
from 8mm thick glass compared to 6.4mm thick glass!
Note:
When less force has been used to break the knife the
stress line falls away rapidly from the knife edge and fewer
saw teeth can be seen.

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Fig.6
Fig.7
Fig.8 Side view Fig.8

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3. Unpacking and Installation
3.1 Unpacking
The Leica EM KMR2, complete with all accessories is packed in a single carton as shown
in Fig.6.
Before unpacking ensure that the box is the correct way up. Having opened the carton,
take the bag with the accessories and the dust cover out of the carton.
Carefully remove the Knifemaker together with the foam plastic (Fig.7).
Remove the foam transport lock of the scoring head (Fig.8).
Check all items against the packing list and examine each item for transport damage.
3.2 Packing list
LEICA EM KMR2, Box glass strips (6.4 x 400 x 25mm)
dust cover and Allen key (no picture) (30 strips)
Knife handling fork (1pc.) Spare scoring wheel cartridge (1pc.)
Knife box (3pcs.) Pair of knives produced with this
LEICA KMR2
3.3 Installation
Place the Leica EM KMR2 on a sturdy laboratory bench or a table where it will not be
affected by movement from other laboratory equipment, such as a centrifuge.
The Leica EM KMR2 is completely assembled in the factory, so the instrument is ready to
use out of the box.

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Fig.9
1234
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4. Description of the LEICA EM KMR2
The scoring and breaking mechanism for knife making are assembled on a heavy,
vibration-absorbing base.
The parts are shown in Fig.9:
1. Clamping lever: is used to lower and raise the scoring head and also to clamp the
scoring head to the clamping head (No.2). For user-preferred positioning the lever can
be adjusted by pulling it horizontally to the left, rotating it and pushing it back.
The best position is horizontal when clamped with glass in place.This way the same
scoring pressure can always be applied during the knife breaking process.
2. Clamping head: carries the scoring head and the clamping lever.
3. Scoring head: carries all necessary elements for scoring and breaking the glass.
The scoring head is lowered into position by means of the clamping lever (No.1).
4. Breaking lever: is used to break the glass after scoring. By turning the lever slowly
clockwise a pin moves against the glass to break it. This lever can be positioned by the
user by pulling it vertically upwards, rotating it and pushing it back.
5. Ruler: acts generally as a stop for the glass strip. The glass strip is pressed against the
ruler before it is clamped. The left hand ruler acts also as a track for the moveable stop with
its four click stop positions.
6. Scoring mark selector: can be set by rotating to two different scoring lengths.
The long score (22 mm) is for scoring the glass strips to break squares for making routine
knives for resin sectioning.
The short score (12 mm) is used to score squares for making high quality knives for cryo
sectioning.
When the long score is used for making knives the quality of the knife is high and also
more reproduceable.
7. Scoring shaft: is pulled out with reasonable speed to the endstop to score the glass
before breaking.
8. Moveable stop with its four cklick positions is mounted on the left hand ruler and is
used to break the 400 mm long glass strips according the balanced break method.
9. Rotatable knob: is used to move the rear stop (No.11) forwards to locate the glass
strips and squares against the ruler.
10. Front stop: is to hold and position squares during scoring and breaking of knives.
11. Rear stop: is used to hold and position the glass strips and the squares against the
front stop (No.10) when breaking knives from the square.

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Fig.10
Moveable stop at
position 1.
Fig.11
Fig.11a

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5. Knifemaking
5.1 Hints
For the best results from your Leica EM KMR 2 it is recommended that glass strips
supplied by Leica are always used. Leica glass strips for ultramicrotomy are produced
from specially selected glass, the thickness and quality of which is precisely controlled.
Only strict tolerances ensured by careful quality control allows breaking of two high
quality knives from one square.
All strips supplied by Leica are 400mm long and 25mm wide.
They are available in thicknesses from 6.4mm, 8mm and 10mm.
Leica glass strips are washed individually wrapped in tissue paper, and packed in a strong
carton. When handling the strips, avoid contacting the narrow edges as these may finally
form the knife edge.
The strips and squares can be held by the wide upper and lower surfaces.
Never touch the corners of a partly broken strip or square as these will
form the knife edge.
Cleaning the glass strips is in general not necessary because the strips are pre-cleaned
wrapped in tissue paper and kept away from dust in the carton.
However, if there is a need to clean the glass:
wash each strip seperately in cool tap water which has a low concentration of a mild
laboratory detergent added to it. Use a soft brush or cloth and take care not to touch the
sharp edges of the strip.
Completely rinse off all detergent, then rinse thoroughly with distilled water. Dry gently with
a clean, soft, lintfree cloth or place it in a drying oven
5.2 Making squares
Set the moveable stop by pressing it on the left hand side to release it and move it to
position 1 (Fig.10). Move the rear stop (Fig.9, No.11) by means of the rotatable knob
(Fig.9, Nr.9) backwards as shown in detail Fig.10.
Place the 400mm long glass strip onto the KMR 2 and push it against the moveable stop,
which is in position 1 (Fig.11). At the same time press the glass strip against the rulers
with the rear stop by means of the rotatable knob (detail Fig.11a). Now lower the
scoring head down onto the glass strip by rotating the clamping lever and tightening it. (
Fig. 11a ). Move rear stop back again.
Note: for reproducible results always lock the clamping lever to
the same position
Note: lowering the clamping head orientates the glass strip
horizontal (parallel) to the surface of the instrument.
To be sure lower the clamping head 2 or 3 times onto the glass
before clamping. Do not hold the glass strip anytime during this
procedure, the glass must be free for self-orientation!
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Warning:
glass knives and glass strips have sharp edges -
handle with great care!

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Fig.12 Fig.13
Fig.14 Fig.15
Fig.16 Fig.17
Moveable stop at
position 2.

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Set the scoring mark selector (Fig.9 No.6) to its long mark.
Score the glass by fast and evenly pulling the scoring shaft as shown in Fig.12.
Rotate the breaking lever gently and slowly clockwise to initiate the
break as shown in Fig.13.
After the break, raise the scoring head completely by means of the clamping lever.
Support the head with a finger below the scoring shaft to prevent the head dropping onto
the glass (Fig.14).
Push back the scoring shaft and bring the breaking lever to its starting point by rotating
anticlockwise (Fig.15).
Place the right hand 200 mm long glass strip onto the working surface of the instrument as
shown in Fig.16.
Move the stop with the 200 mm long glass strip to position 2 as shown in Fig.16 and push
the glass strip against it.
Press the glass strip by means of the rear stop against the rulers, lower the scoring head
by means of the clamping lever down onto the glass strip (2 or 3 times) and pull the
clamping lever tight. Move rear stop back again.
Score, break and raise the scoring head as before.
The result is now two 100 mm long strips.
Place the right hand 100 mm long glass strip to the rear of the working suface of the
instrument.
Move the stop with the 100 mm long strip to position 3.
Press the strip by means of the rear stop against the rulers, lower the scoring head and
clamp it. Move rear stop back again.
Score, break and raise the scoring head as before.
The result is now two 50 mm long strips.
Place the right hand 50 mm long glass strip to the rear of the working surface of the
instrument.
Move the stop with the 50 mm long strip to position 4.
Support the 50 mm glass strip by placing the handling fork under the glass strip for easier
handling of the resulting squares as shown in Fig.17.
Press the strip by means of the rear stop against the rulers, lower the scoring head and
clamp it. Move rear stop back again.
Score, break and raise the scoring head as before.
The result is now two 25 mm squares as shown in Fig.18.
Fig.18

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Freshly broken side!
Freshly broken side!
Fig.21
Fig.22
Notch of the front stop.
Notch of the rear stop.
Fig.23

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End broken by
manufacturers - not perfect!
5.3 Making knives from square
Set the moveable stop to position 1 as it is not used for breaking knives.
Scoring head is raised completely, breaking lever turned anticklockwise to its start
position, scoring shaft is pushed back and the rear stop is moved back.
Place a square onto the handling fork and rotate it a quarter turn clockwise (Fig.21)
to produce the knife edges fom the freshly broken sides of the glass.
Place the square using the handling fork onto the two pins and make sure that the corners
of the square are positioned into the notch of the front and rear stops (Fig.22).
Move the rear stop by means of the rotatable knob carefully against the square making
sure you do not touch the corners.
The square is now held firmly between the two stops. Open and close the rear stop
2 or 3 times to ensure the glass is correctly positioned.
The handling fork lies loose underneath the square (Fig. 23).
Lower the scoring head by means of the clamping lever down onto the square 2 or 3 times
then pull clamping lever tight.
Set the scoring mark selector to its short or long mark.
Score the glass by quickly and evenly pulling the scoring shaft to the end stop.
Rotate the breaking lever gently and very slowly clockwise to initiate the break.
The slower the better.
Note: As the left end of the left hand 200 mm glass strip is machine
broken by the glass manufacturers and therefore geometrically not
perfect do not use this square for breaking knives (Fig.19).
Also, the outer square of the right hand 200 mm glass strip is
not used to make knives (Fig.20) for the same reason.
Fig.19 Fig.20
Note: The best knives are made using the
lowest breaking pressure.
They may take a minute or more to break!

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Fig.24
Fig.25
Fig.26
Fig.27