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About Properties of Metals  1- Properties are the characteristics of any material indicating its behavior and performance under different conditions of working on it or during its use.  2- Properties of metals can be broadly categorized as follows.    i • Physical properties      ii • Mechanical properties    iii • Chemical properties Physical properties  1- Physical properties are those properties which remain unchanged when metals are heated, electrical current is passed, the metal is melted or magnetized. 2- Important physical properties include,     • Color      • Weight/Specific gravity      • Structure • Conductivity      • Magnetic property      • Fusibility Color  1- Different metals have different colors. For example, copper is of a distinctive red color.  2- Mild steel is of a blue/black sheen. Weight  1- Metals differ based on their weight.  2- A metal, like aluminum, weighs lighter (specific gravity 2.8) than many others and a metal, like lead, is heavy (specific gravi

What is Scraper Tool Use 1- It is a specific type of operation of removing convex spots from the machined surface and the tool used for removing complex spot is called scraper .  2- For obtaining a fine surface finish,  3- It is a very important hand. Operation employed.  4- Depending upon the specific work to be performed, scrapers vary in size and shape. 5- Scrapers are usually made out from warmouth or used old files that can't be used for further filing work.  6- For manufacturing scrapers , the files are heated to forging temperature and forged to the required shape.   7- Then further hardening and tempering operations are performed on files to get the desired hardness.  8- The cutting edge of the scraper is ground to sharpen it for removing the material.  9- The toolmaker's scraper is knurled at one end while the other end has the cutting edge. Types and uses of scraper  1- Flat scraper . 2- Hook scraper. 3- Half round scraper . 4- Circular scraper . Flat scraper 1-

 What is Power Tool's   1- A power tool is a tool actuated by power source and mechanism other than manual labor used with hand tools for fastening bolts and nuts .  Power wrench  1- A power wrench is type of wrench that is powered by other means than human force.   2- A typical power source is compressed air .   3- There are two main types of power wrenches :  i- Impact Wrenches and  ii- Air ratchet or pneumatic ratchet wrenches. Pneumatic torque wrench  1- A pneumatic torque wrench is a primary torque multiplier or a gear box that is mated to a pneumatic air motor. 2- At the end of the gear box is a reaction device that is used to absorb the torque and allows the tool operator to use it with very little effort .  2- The torque output is adjusted by controlling the air pressure .  3- These planetary torque multiplier gearboxes have multiplication ratios up to 125 : 1 and are primarily used anywhere accurate torque is required on a nut and bolt , or where a stubborn nut ne

 Standard and Special Screwdrivers and their Uses  1- Screwdrivers are used to tighten or loosen screws which are fixed in the machine element .  Classification of Screwdrivers  1- Standard type  Screwdrivers  with tips to suit recessed head screw slots .  2- Special type  Screwdrivers  with tips to suit recessed head screws .  Features of standard screwdrivers  1- Screwdrivers must have :  i- Tips to turn screws with slotted heads. ii- Handles of metals , wood or molded insulating material , shaped to give a good grip for turning . iii- Blades of hardened and tempered carbon steel or alloy steel .  iv- Round or square blade with length ranging from 40 mm to more than 350 mm.  v- Flared tips which vary in length and thickness with the length of the blade .  Standard Screwdrivers  1- Standard screwdrivers are classified as  i - Heavy duty screwdrivers .  ii- Light duty screwdrivers . iii- Stumpy screwdrivers .  Heavy duty screwdrivers 1- This screwdriver has a square blade for ap

 Why Lathe Accessories Use in Lathe Machine?  1- The lathe accessories are independent units supplied along with the lathe .  2- The lathe accessories are essential for the full utilization of the lathe .  3-   Lathe accessories  can be grouped into two types i- work-holding  Lathe  accessories   ii- work-supporting  Lathe  accessories.   Work-holding  Lathe  accessories  1- The work can be directly mounted and held on these accessories.  2- The following are work-holding accessories.  i- Four jaw independent chuck. ii- Three Jaw Chuck iii- Face Plate iv- Lathe Mandrels. work-supporting  Lathe  accessories 1- These accessories do not hold the work themselves. 2- These accessories only for Supporting the work. 3- The following are the work-supporting accessories. i- Catch Plate. ii- Driving Plate. iii- Lathe Centers. iv- Lathe Carriers. v- Steady Rest. Chucks  1- Chucks are used to hold workpieces of short length and large diameters or irregular shapes .  2- This is attached to

 What is Soldering ? 1- Soldering is a process of giving a permanent nature to a joint of wires.  2- Unsoldered joints become loose and oxidized after some time and cause sparking.  3- It is necessary to ensure that the melting point of the metal to be soldered should be high enough than the melting point of the metal used as a solder.  4- Soldering is a process in which a metal or a metal alloy having a low melting point is filled in a pre heated joint in the molten state.  5- This molten metal alloy fills the blank space of the joint and make the joint permanent.  6- The process of soldering is quite easy and it requires a little practice only. Metals used for making solders  1- Generally, a solder is an alloy metal which melts at a low temperature. An alloy metal is a mixture of two or more metals.  2- The metal and its percentage in the mixture depends on its use.  3 There are two main types of solders which are as follows,  1- Hard solder,  2- Soft solder   Hard solder 1- Th