BM 2609140260 7-05 7/26/05 10:02 AM Page 15
Operating Tips
You will extend the life of your bits and doThe largest tightening torque is achieved
neater work if you always put the bit inafter approx. 6 to 10 Sec. impacting/
contact with the work before pulling thetightening action.
trigger. During the operation, hold the tool
The torque build-up depends on the
firmly and exert light, steady pressure. Too
following factors:
much pressure at low speed will stall the tool.
Too little pressure will keep the bit fromY Hardness of the bolts/nuts.
cutting and cause excess friction by sliding
Y Type of washer (disk washer, spring
over the surface. This can be damaging to
washer, seal).
both tool and bit.
Y Hardness of the material to be joined.
DRIVING WITH VARIABLE SPEED
The technique is to start slowly, increasingY Lubricating effect at the surfaces of the
the speed as the screw runs down. Set thejunction.
screw snugly by slowing to a stop. Prior to
This leads to the following application cases:
driving screws, pilot and clearance holes
should be drilled.Hard case: The joining of metal to metal with
a disk washer. The maximum torque is
Always hold the machine straight on the bolt
reached after a relative short impacting/
to be tightened.
tightening action.
The best method to determine the right
impacting/tightening duration is by means ofMedium case: The joining of metal to metal
a trial. For small screws, the rightwhere spring ring washer, disk spring
impacting/tightening duration can be reachedwasher, stud bolts or bolts/nuts with conical
in less then 0.5 Sec. Therefore, work withseats are used.
low RPM and switch the machine off
Soft case: The joining of e.g. metal to wood
immediately when the screw is tight and the
or insulation material.
impacting sound can be heard.
For middle or soft joining cases, the
For screwing larger, longer wood screws into
maximum tightening torque is less as for
hard material, pre-drilling is the best method.
hard cases. Therefore, a longer impacting/
TIGHTENING TORQUEtightening action is necessary to arrive at the
The tightening torque depends on themaximum tightening torque.
duration of the impacting/tightening action.
2. Drill same
FASTENING
FASTENING WITH SCREWSdiameter as
WITH SCREWSscrew shank.
This procedure shown in (Fig. 12) will enable
you to fasten materials together with your tool
3. Countersink
without stripping, splitting or separating thesame diameter1. Drill 2/3 diameter and
2/3 of screw length for
material.as screw head.soft materials, full
length for hard
First, clamp the pieces together and drill thematerials.
first hole 2/3 the diameter of the screw. If the
material is soft, drill only 2/3 the proper
length. If it is hard, drill the entire length.
Second, unclamp the pieces and drill the
Screw
second hole the same diameter as the screw
Apply a slight
shank in the first or top piece of wood.even pressure
when driving
Third, if flat head screw is used, countersinkscrews.
the hole to make the screw flush with the
surface. Then, simply apply even pressure
FIG. 12
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ACEC
BOSCH
