Sunday, April 13, 2014

Electric work01 -Hand Tools

          Hand tools are the tools which are used by human in a workshop for various electrical installation related works and also for various maintenance works.

Types of hand tools

1. Screw driver
A hand tool used to fix and remove screws. Used in assembling work and maintenance work. Available in three main types:

a) Flat type – Point of the screw driver is flat shape used for straight slot screws.
b) Pozidriv type (Philips type) - Point of the screw driver is special shape (x shape) to match with             the slot in pozidriv slot screw. Used for Pozidriv slot screws.
c) Offset screw driver – Designed for use in confined areas where it is impossible to use a standard         screw driver.

2. Pliers
A hand tool, used to hold smaller components for various activities such filing, drilling etc. We can cut wires pulled out tighten small components by using pliers.

3. Hammer
A hand tool used for delivering blows (force) in chipping using chisel, bending, straightening and other operations. Hammers are forged from high carbon steel. Hammer sizes are specified by their weight. Main types of hammers are:

a) Ball pein hammer – Most commonly used hammer. Consists of flat face for general work and ball         pein for peining or riveting.
b) Cross pein hammer – Used for sheet metal forming
c) Straight pein hammer – Used for sheet metal work

4. Tape measure
 A tape measure is a portable measurement device used to quantify the size of an object or the distance between objects. The tape is marked along the tape edge in inches and fractional inches, typically in quarter-, eight-, and sixteenth-inch increments. Some tape measures are marked in millimeters, centimeters, and meters on one edge.
The most common tape measures are 12 feet, 25 feet, or 100 feet in length.

Portable power tools suitable for drilling walls

Hand drilling machine
 Manually hand operated drilling machine. Used for rough and smaller diameter hole drilling.(Up to about 5mm dia.) Mostly used to drill soft materials.

Portable electric Drilling machine 
 Electrically operated hand drill. Used for rough and small diameter hole drilling (up to about 18mm dia.)Spindle is driven by the electric motor and feeding of drill is done by human hand. Can drill metals also.

Hammer drill
 A hammer drill has a specially designed clutch that allows it to not only spin the drill bit, but also to punch it in and out (along the axis of the bit). Hammer drills are more expensive and more bulky than regular drills, but are preferable for applications where the material to be drilled—concrete block or wood studs—is unknown. For example, an electrician would use a hammer drill for attaching items (such as an electrical box) to either wood studs (if used as a conventional power drill) or masonry walls (if used as a hammer drill).

Drill bit
The cutting tool used on a drilling machine is known as a Drill bit ( Drill). The most common type of drill is Twist Drill.
Twist drill
Twist drill is consists of 2 main parts:
i) Body – A cylindrical part make with 2 helical flutes to provide the cutting lips and cutting point to remove the chips. To  reduce the friction of the body and the point against the walls of the hole and for better guiding of the tool, only a part of the cylindrical surface is left project and form what are called the lands.
ii) Shank – The part of the drill which to the machine. Depend on the method of applied to securing the drill, the shank available as
a) Straight or Cylindrical type – Available as drills which are less than 12.7mm in diameter. When fixing the straight shank drills to a drilling machine a Drill chuck or a Collet chuck is used.
b) Taper Shank – Consists of standard Morse taper shank. Available as drills which are more than 12.7mm in diameter. When fixing the taper shank drills to a drilling machine the Morse tapered spindle hole or Morse tapered sleeve is used.

Types of twist drill

General purpose drill – a drill with standard helix angle or Rake angle of 60°. Used to drill mild steel, cooper alloy etc.
Slow helix drill – A drill with larger helix angle , Used to drill hard materials
Quick helix angle - A drill with smaller helix angle , Used to drill  soft materials
Straight flute drill – Flute which take straight shape. Used to drill very soft material
Flat drill – A drill without a point. Used to drill sheet metal


Post a Comment

Twitter Delicious Facebook Digg Stumbleupon Favorites More