7OPERATION012050The proper fastening torque may differ depending uponthe kind or size of the screw/bolt, the material of theworkpiece to be fastened, etc. The relation betweenfastening torque and fastening time is shown in thefigures.120100806040200 1.0 2.0 3.0M14M12M10M8(M14)(M12)(M10)(M8)Standard boltN mFastening torqueFastening time (S)Proper fastening torque(kgf cm)(1224)(1020)(816)(612)(408)(204)006255120(1224)100(1020)80(816)60(612)40(408)20(204)0 1.0 2.0 3.0M12M10M8(M12)(M10)(M8)N mFastening torqueFastening time (S)Proper fastening torque(kgf cm)High tensile bolt006257Hold the tool firmly and place the point of the driver bit inthe screw head. Apply forward pressure to the tool to theextent that the bit will not slip off the screw and turn thetool on to start operation.NOTE:• Use the proper bit for the head of the screw/boltthat you wish to use.• When fastening screw M8 or smaller, carefullyadjust pressure on the switch trigger so that thescrew is not damaged.• Hold the tool pointed straight at the screw.• If you tighten the screw for a time longer thanshown in the figures, the screw or the point of thedriver bit may be overstressed, stripped, damaged,etc. Before starting your job, always perform a testoperation to determine the proper fastening time foryour screw.• If you use a spare battery to continue the operation,rest the tool at least 15 min.The fastening torque is affected by a wide variety offactors including the following. After fastening, alwayscheck the torque with a torque wrench.1. When the battery cartridge is discharged almostcompletely, voltage will drop and the fasteningtorque will be reduced.2. Driver bit or socket bitFailure to use the correct size driver bit or socketbit will cause a reduction in the fastening torque.3. Bolt• Even though the torque coefficient and theclass of bolt are the same, the proper fasteningtorque will differ according to the diameter ofbolt.• Even though the diameters of bolts are thesame, the proper fastening torque will differaccording to the torque coefficient, the class ofbolt and the bolt length.4. The manner of holding the tool or the material ofdriving position to be fastened will affect the torque.5. Operating the tool at low speed will cause areduction in the fastening torque.MAINTENANCECAUTION:• Always be sure that the tool is switched off and thebattery cartridge is removed before attempting toperform inspection or maintenance.• Never use gasoline, benzine, thinner, alcohol or thelike. Discoloration, deformation or cracks mayresult.