1. WRENCHES

2. OBJECTIVES IDENTIFY VARIOUS TYPES OF
WRENCH,THEIR USES AND MAINTENANCE.
DETERMINE THE CORRECT USED OF SELECTED TOOLS.

3. INTRODUCTION
A WRENCH is a tool for turning nuts or bolts, usually made of steel. They are named (1) from their shape (2) from the object on which they are used, tap wrench & pipe wrench (3) from their construction, such as the spanner wrench and ratchet wrench.

4. TYPE OF WRENCH
SINGLE ENDED WRENCH – is one that is made to fit one size of nuts or bolts.
This is most inexpensive type of wrench and is quite efficient in ordinary
situations.

5. DOUBLE ENDED WRENCH-has two openings,open at each end of the hand to fit two different sizes of nuts or bolt heads.

6. CLOSE END WRENCH(BOX WRENCH)-similar to single ended wrench but entirely
enclosed a nut.

7. ADJUSTABLE WRENCH-have movable jaws,which make it adjustable to various sizes of nuts.A heavy type of this wrench
is called a monkey wrench.

8. LEVER JAW WRENCH-a combination gripping tool with
adjustable jaw,which may be locked in place,it may be used as a wrench,clamp,pliers,or vise.

9. COMBINATION WRENCH-has two types of opening of the same size.

10. TOOL POST WRENCH-square box, and it is designed to fit toolpost screw and set screw on lathes and other machining tools.
See also square box wrench

11. T HANDLE TAP WRENCH-it is used to hold and turn small cups
up to about ½ “.

12. 12-POINT BOX WRENCH – designed with 12 notches, or point inside a closed end, which permits a turning of nuts where only a short pull of the wrench possible.

13. T-SOCKET WRENCH – is made in the form of T where the socket in the end is made in a variety of shapes, such as square, hexagonal, octagonal,it is generally used to jobs when there is insufficient space to permit the use of an ordinary wrench.

14. STRAP WRENCH - it used for turning cylindrical parts, pipes.

15. PIPE WRENCH – is designed with adjustable jaws that are serrated making it possible to
grip around pipes and other
cylindrical parts.

16. ALLEN WRENCH – (Key wrench) is made of hexagon-shaped stock to fit the holes in the head of set screw or socket head screws.

17. TORQUE WRENCH – is used when it is necessary to know the amount of turning or twisting force being applied to a nut.

18. GUIDELINES IN USING WRENCHES:
Always select a wrench which fits the nut or bolt properly. A wrench that is too large may slip off the nut and possibly cause an accident.

19. Whenever possible, it is advisable to pull rather than push on a wrench in order to avoid injury if the wrench should slip.
Always be sure that the nut is fully seated in the wrench jaw.

20. Use a wrench in the same plane as the nut or bolt head.
When tightening or loosening a nut, a sharp quick jerk is more effective than a steady pull.

21. A drop of oil on the threads when assembling a bolt and nut will ensure easier removal later.

22. END