WORKSHOP TECHNOLOGY-Hand Tools and its Operation

WORKSHOP TECHNOLOGY-Hand Tools and its Operation

1. Hand tools and operation Tribhuvan University Institute of Engineering (IOE) Himalaya College of Engineering Man without Tools is nothing; with tools he is all. Prepared By: Er . Amrit Tiwari Lecturer Himalaya College of Engineering

2. Hand tools Efficiency of any hand processes is low and the outcome quality depends highly upon the skill of individuals. Advantages : Less Dangerous Flexibility Always Work Final Assembly One which is powered by hand ( manual labor) rather than by an engine.

3. Different types of hand tools Vice holding the work piece where most hand processes to be carried out. Body made up of cast iron and jaws are made up of hardened tool steel Care of Vices Do not direct impact the vice body by the hammer. Light hammering can be done on and only on the anvil of the vice. To avoid over clamping, the handle of the vice should be tightened by hand only

4. Files for the removal of materials made of hardened high carbon steel Hand File Half round File Round File Square File Three square File Flat File

5. 1 . Hand File - The common file used for roughing and finishing. It is a rectangular in section and parallel in width. It has double cut teeth on two faces, single cut teeth on one edge, and one save edge. 2. Flat File - It is similar to a hand file rectangular in section, tapered slightly in width and thickness towards the tip. It has Double Cut teeth on two faces and Single Cut teeth on two sides. 3. Half-round File - The section is a chord of a circle with its taper towards the tip. It is used for forming radii, grooves, etc. and the flat side is used for finishing flat surfaces.  

6. 4. Round File - This is of round section tapering toward the end. It is used for enlarging holes, producing internal round corners. Usually double cut in the larger sizes, and single cut for the smaller sizes. 5. Square File - This is square in section, with tapered towards the tip, and usually double cut on all four faces. It is used for filing rectangular slots or grooves. 6. Three Square File - It is also known as triangular file. This is a triangular in section, with tapered towards the tip with double cut on both faces. It is used for filing corners or angles less than 90°

7. Needle Files - Needle files are a set of small files with their shapes made in a way similar to the large ones. They are generally used for small and delicate works such as the repair of small instruments.

8. Grade - pitch (spacing) of the teeth Rough- 8 teeth per cm Middle or coarse-10 teeth per cm Bastard cut – 12 teeth per cm Second cut – 16 teeth per cm Smooth cut – 20 to 24 teeth per cm Dead smooth cut- 40 or more teeth per cm Cut Pattern Single Cut Double Cut File Card File card= Removal of pinning

9. Precautions in filing Files teeth are brittle and therefore file should be placed properly and should not be stacked on other tools. New files should never be used on hard materials. Remove the pinning regularly by a file card/wire brush. It is very danger to use files without handles. Filing process Cross filing Draw filing

10. Hacksaw cutting a metal into pieces consists of a frame and a saw blade frame may be of fixed type or adjustable type a wing nut to adjust the tension of the blade Saw blade made of high carbon steel, alloy steel or High Speed Steel

11. Precautions in Sawing The cutting action is carried on the forward action only. So the blade must be mounted with its teeth pointing forward. Suitable tension should be applied on the blade to avoid breakage or loosen. Change the blade if some teeth are broken. Avoid rapid and erratic strokes of cut. Avoid too much pressure. Work piece must be hold firmly.

12. Marking Out Tools Punch Scriber Engineer's Square Spring Dividers

13. Threading Tools- Taps and Dies Used to create screw threads Tap- Create internal thread in hole part( e.g.Nut ) Die- Create external thread in shaft part (e.g. Bolt) Tap Die

14. Precautions in Threading The size of the hole is important and the correct drill size should be determined from the handbook, standard table in the workshop or the recommendation on the shank of the tap . Ensure that the die is set perpendicular to the rod. Always use the correct size of wrench for the tap in use. Lubricant oil should be used. Use both hands to hold the wrench to maintain even torque. About every half turn reverse action slightly to break the swarf and clear the threads.

15. Hammer Basic tool of many professions . Consists of a handle and a head, with most of the weight in the head . Different types of hammers used in different profession Claw Hammer Straight peen Hammer

16. Sledge Hammer Ball peen Hammer Mallet Hammer Pliers and cutters Used for bending and compression Handling hot metals Cutting electrical communication

17. Wrenches Used to provide grip and mechanical advantage in applying torque to turn objects Rivets a metal pin for passing through holes in two or more plates or pieces to hold them together permanent mechanical fastener

18. Measuring tools Vernier Height Gauge Micrometer Vernier Calipers Outside Calipers Inside Calipers Dial Indicator Combination Set

19. Least Count The  least count  of an instrument is  the smallest  measurement that can be taken. Least count is difference between the value of main scale and vernier scale. i.e . L.C. = value of smallest division on main scale- value of smallest division on vernier scale. Or L.C.= value of smallest division on main scale/ total no. of division in vernier scale Reading= Value in Main Scale+ vernier scale coinciding with main scale * L.C.