For screwing larger, longer wood screws intolength. If it is hard, drill the entire length.
hard material, pre-drilling is the best method.Second, unclamp the pieces and drill the
TIGHTENING TORQUEsecond hole the same diameter as the screw
shank in the first or top piece of wood.
The tightening torque depends on the
duration of the impacting/tightening action.Third, if flat head screw is used, countersink
The largest tightening torque is achievedthe hole to make the screw flush with the
after approx. 6 to 10 Sec. impacting/surface. Then, simply apply even pressure
tightening action. when driving the screw. The screw shank
clearance hole in the first piece allows the
The torque build-up depends on the
screw head to pull the pieces tightly together.
following factors:
RUNNING NUTS AND BOLTS
Y Hardness of the bolts/nuts.
Variable speed control must be used with
Y Type of washer (disk washer, springcaution for driving nuts and bolts with socket
washer, seal).set attachments. The technique is to start
Y Hardness of the material to be joined. 2. Drill same
FASTENINGdiameter as
WITH SCREWSscrew shank.
Y Lubricating effect at the surfaces of the
junction.
3. Countersink
1. Drill 2/3 diameter and
This leads to the following application cases:same diameter2/3 of screw length for
as screw head.soft materials, full
Hard case: The joining of metal to metal withlength for hard
materials.
a disk washer. The maximum torque is
reached after a relative short impacting/
tightening action.
Medium case: The joining of metal to metal
where spring ring washer, disk springScrew
Apply a slight
washer, stud bolts or bolts/nuts with conical
even pressure
seats are used. when driving
screws.
Soft case: The joining of e.g. metal to wood
or insulation material.
For middle or soft joining cases, theFIG. 6
maximum tightening torque is less as for
slowly, increasing speed as the nut or bolt runs
hard cases. Therefore, a longer impacting/
down. Set the nut or bolt snugly by slowing the
tightening action is necessary to arrive at the
tool to a stop. If this procedure is not followed,
maximum tightening torque.
the tool will have a tendency to torque or twist
FASTENING WITH SCREWSin your hands when the nut or bolt seats.
Fig. 6
you to fasten materials together with your tool
without stripping, splitting or separating the
material.
First, clamp the pieces together and drill the
first hole 2/3 the diameter of the screw. If the
material is soft, drill only 2/3 the proper
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