CHANGING THE CHUCK

Removing the chuck: First it is necessary to remove the chuck securing screw. This screw is left-hand threaded and is accessible after the chuck jaws are fully opened. Next remove the chuck by placing the shorter arm of a 3/8 “ hex key in the chuck and tighten the chuck onto the hex key. Use a 17mm open end wrench (not provided), on the spindle flats, to prevent the spindle from turning. Lay the tool on a flat surface and while holding the tool securely, strike the hex key sharply with a hard rubber mallet in the same direction as forward drill rotation. Unthread the chuck from the spindle (Fig. 3).

INSTALLING CHUCK

Always keep the spindle threads, the threads of the chuck and securing screw free of debris. To install a chuck, reverse “removing the chuck” procedure.

FIG. 3

CHUCK

SECURING

SCREW

Operating Tips

You will extend the life of your bits and do neater work if you always put the bit in contact with the work before pulling the trigger. During the operation, hold the tool firmly and exert light, steady pressure. Too much pressure at low speed will stall the tool. Too little pressure will keep the bit from cutting and cause excess friction by sliding over the surface. This can be damaging to both tool and bit.

DRILLING WITH VARIABLE SPEED

The trigger controlled variable speed feature will eliminate the need for center punches in hard materials. The variable speed trigger

allows you to slowly increase RPM. By using a slow starting speed, you are able to keep the bit from “wandering”. You can increase the speed as the bit “bites” into the work by squeezing the trigger.

DRIVING WITH VARIABLE SPEED

Variable speed drills will double as a power screwdriver by using a screwdriver bit in the drill mode. The technique is to start slowly, increasing the speed as the screw runs down. Set the screw snugly by slowing to a stop. Prior to driving screws, pilot and clearance holes should be drilled.

FASTENING WITH SCREWS

The procedure shown in (Fig. 4) will enable you to fasten materials together with your hammer drill in the drill mode without stripping, splitting or separating the material.

The adjustable screw drill accessory will do all of these operations quickly and easily. Screw drills are available for screw sizes No. 6, 8, 10 and 12.

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 length. If it is hard, drill the entire length.

Second, unclamp the pieces and drill the second hole the same diameter as the screw shank in the first or top piece of wood.

FASTENING WITH SCREWS

1.Drill 2/3 diameter and 2/3 of screw length for soft materials, full length for hard materials

Screw

2.Drill same diameter as screw shank

3.Countersink same diameter as screw head

Adjustable

Screw

Drill

Third, if flat head screw is used, countersink the hole to make the screw flush with the surface. Then, simply apply even pressure when driving the screw. The screw shank clearance hole in the first piece allows the screw head to pull the pieces tightly together.

-8-

Apply a slight even pressure when driving screws

FIG. 4

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Bosch Power Tools 1169VSR manual Operating Tips