Baroness LM2700 Manual

Technical Information Leaflet
TIL: 003
LM2700 Backlapping

BACK-LAPPING A BARONESS LM2700
If you are unable to obtain a satisfactory cut with just a light blade contact then you will need to back-
lap the cutting cylinders.
Back-lapping is an interim method of keeping the blades sharp in between re-grinding.
Before you start the process you will need the following:
A long handled brush. This can be made by using a wallpaper paste brush and extending the
handle by using a suitable length of tube. It is important to have the handle extended so that
your hands are nowhere near the rotating blades during the back-lapping process.
A pot of back-lapping paste. Back-lapping
paste is a water soluble abrasive grinding
paste.
It is available in different grades but the grade
that we would recommend for back-lapping
Baroness blades is 80 grit, or Course.

Firstly adjust the contact between the
cutting cylinder and the bottom blade
to achieve the best cut possible
keeping the contact even across the
entire width of the blades.
Then increase the contact so that it is
slightly heavier than you would use
for cutting, but still make sure that
the cylinder rotates with just a light
pressure.
Repeat this for all 5 cutting units.
Turn off all five cutting unit hydraulic
motors using the lever shown.
Swing out the rear units by removing
the unit positioning pin.

Your assistant should remain on the seat throughout the process and should be fully briefed and
familiar with the emergency shut-down procedure.
With the aid of an assistant and with the
parking brake on, start the engine and
leave it running at idle. The assistant
should remain on the seat and able to
stop the machine in an emergency.
With the engine running select cutting
cylinder reverse (switch back). Please
note that on newer models you will find
this switch located under the engine
cover on the right hand side just below
the relays.
Turn the cutting reels on by pressing this
switch forward.
Select the cross-cut position of the cutting
units by pressing this switch forward.
Lower the units to the floor by pushing this
leaver forwards. Please note that the
cutting cylinders should not be rotating as
these were turned off at the motors earlier
in the process.
Select the first cutting unit that you
want to back-lap and turn the unit on
using the hydraulic motor selection
lever as shown.
The cutting cylinder should now start
rotating in a reverse direction.
Note: Do not perform the back-
lapping process with the cylinders
rotating in the normal cutting
direction.

After applying the abrasive paste several times to the cutting cylinder, leave it to rotate during which
time the grinding noise should progressively lessen.
With the first cylinder still rotating, move on to the second cutting unit and repeat the process. After
you have applied the cutting paste to the second unit several times, leave this unit to continue rotating.
With the second cylinder still rotating, go back to the first cylinder and turn it off at the motor using the
lever.
Dip the long handled brush into the back-lapping
paste until the brush has a good covering of the
abrasive paste.
Apply the back-lapping paste to the top
of the rotating cutting cylinder using
the long handled brush as shown.
Do not allow the brush to enter too far
into the cutting cylinder as this could
pull the brush into it. Simply allow the
tips of the brush bristles to flick the
rotating cutting cylinder.
Move the brush from side to side
covering the full width of the blades
with paste.
Repeat this several times, reloading the
brush with abrasive paste each time.

Next, move on to the third unit and repeat the process.
With the third cylinder still rotating, go back to the second one and turn it off.
Work your way around all 5 cutting units as described above so that you only ever have two units
rotating at once, as having the cylinders running dry for a prolonged period of time can cause damage to
the blades.
Once all 5 units have been back-lapped you
will need to thoroughly wash the back-
lapping paste from the blades.
The best way to do this is to turn the units
on one at a time, and with them rotating
direct a jet of water at them. Move the
hose from left to right until all of the paste
is removed.
Turn each unit off after you have finished
washing it before moving on to the next
unit.
Once the cutting units are dry, check
the cut using a strip of paper.
Normally after back-lapping, no further
adjustments are necessary, however, you
might need to readjust the cut slightly by
bring the cylinder down onto the bottom
blade using the adjusters as shown.
If after back-lapping you still cannot get
the unit to cut properly then you might
have to repeat the back-lapping process or
even consider having the units re-ground.