Bosch GNA 3,5 Professional Original Operating Instructions page 6

OBJ_BUCH-555-004.book Page 6 Thursday, April 14, 2016 9:28 AM
6 | English
Switching On and Off
To start the machine, push the On/Off switch 5 forwards.
To lock the On/Off switch 5, additionally push down the front
of the switch.
To switch off the machine, release the On/Off switch 5. When
the On/Off switch is locked, press on the rear of the switch
and then release it.
Working Advice
 Before any work on the machine itself, pull the mains
plug.
 The power tool is not suitable for stationary operation.
For example, it may not be clamped in a vice or fastened on
a workbench.
 Wear protective gloves while working and pay particu-
lar attention to the mains cable. Sharp burrs develop at
the cut steel sheet and can cause injuries to the operator or
damage the mains cable.
 Exercise caution when handling the cutting chips. The
chips have sharp tips that can cause injuries.
Apply the machine to the workpiece only when switched on.
Always hold the machine vertical to the surface of the steel
sheet and do not tilt it.
The cut takes place during the downward motion of the
punch. Guide the machine evenly and with moderate feed in
the cutting direction. A high feed rate significantly reduces
the service life of the cutting tools and can damage the ma-
chine.
The machine operates more quietly when it is raised slightly
during cutting. If the punch should become wedged during
cutting, switch the machine off, relubricate the punch and re-
lease the tension of the steel sheet. Do not exert force, other-
wise the punch and the die will become damaged.
Maximum Steel Sheet Cutting Capacity
The maximum steel sheet cutting capacity d
the strength properties of the material to be cut.
The machine allows for straight and deformation-free cutting
of metal sheets to the following thicknesses:
Material Max. strength property
2
[N/mm ]
Steel 400
600
800
Aluminium 200
Lubricating/Cooling the Punch
To extend the service life of the punch 10, a lubricating agent
with good cooling properties (e.g. cutting oil) should be used.
Apply a trail of lubricant beads onto the top side of the metal
sheet alongside the intended cutting line. For long periods of
continual use or for work with high frictional wear (e.g. when
cutting aluminium), the cutting head should be immersed into
a container with lubricant in regular intervals.
1 609 92A 1XG | (14.4.16)
Cutting along a Cutting Mark or with a Guide
The projection on the hold down guide 12 serves as a cutting
mark after having made the incipient crack.
Straight cuts are carried out easier when the machine is guid-
ed alongside a rule.
For inside cuts, pre-drilling a hole with a diameter of 41 mm is
necessary.
Maintenance and Service
Maintenance and Cleaning
 Before any work on the machine itself, pull the mains
plug.
 For safe and proper working, always keep the machine
and ventilation slots clean.
Clean and lubricate the punch 10, die 14 and guide plate 11
every 3 operating hours.
Change the punch, die and guide plate in good time when
worn. Only sharp tools produce a good cutting quality and
make the machine last longer.
Changing the Die
Loosen and remove both screws 9. Insert a new die and tight-
en it firmly with the screws 9.
A worn die must not be reground.
Changing the Guide Plate
The guide plate 11 is used to protect the die holder 15.
To change the guide plate, remove the die 14 (refer to
"Changing the Die"). Loosen and remove the screws 13 on
the hold down guide. Remove the hold down guide 12 and the
guide plate 11.
Insert a new guide plate. Attach the die with the screws 9 and
the hold down guide via the screws 13. Tighten the screws.
Changing the Punch
depends on
max
Insert the allen key 4 into the screw head of the punch adjust-
ment screw 16. Turn the adjustment screw until it 7 is exact
centre of the borehole 8 at the die holder. Remove the allen
key from the punch adjustment screw 16.
d
Remove the die 14 (refer to "Changing the Die" as well as the
max
[mm]
hold down guide 12 and the guide plate 11 (refer to "Chang-
ing the Guide Plate").
3.5
Loosen the screw 7 of the punch fastener and pull out the
2.4
punch 10 downward. Lubricate the new or the reground
1.6
punch properly and insert it from underneath. Tighten the
4.0
screw 7 again.
Attach the guide plate 11 and the hold down guide 12 as well
as the die 14 (refer to "Changing the Guide Plate" as well as
"Changing the Die").
Regrinding the Punch
In most cases, regrinding the punch in good time (e.g. with a
diamond disc) can usually prevent the punch from breaking
out. Heavily damaged punches may not be reground.
Bosch Power Tools