1.Surface Plate
Surface plate is made of grey cast iron of solid design. It is used for testing the flatness of work
and also used for marking-out the work. A surface plate has a surface of proved flatness. When
used for testing flatness, the top of the plate should be coated with their layer of red lead in oil.
The surface to be tested must be cleaned, then place in contact with the plate and moved about. If
it is reasonably flat, subsequent examination will show spot of blue or red all over the surface.
2.V - Block: It is made of hardened steel with V-shaped grooves on the top and bottom, and
rectangular slots on two sides for the location of clamps. Roundly shaped work pieces which are
to be marked or drilled are placed on V-supports. In this way, they are firmly supported in a
horizontal position and cannot rotate easily.
3.Scribers: It is made of tool steel with hardened and tampered points and knurled on the
body to provide grip. Scriber is used for making straight lines on metal surface with the aid of
steel rule, try square and templates. The bent end is used to scratch line in places where the
straight end cannot reach. The ends are sharpened on an oil stone when necessary.
4.Angle plate: This is used in conjunction with the surface plate for supporting work in the
perpendicular position. It is made of grey cast iron has two plane surfaces at right angles to each
other. It has various slots in it to enable the work to be held firmly by bolts and clamps.
5.Punches: Punches are used in a bench work for marking out work, locating centres, etc. in
permanent manner. It is made of tool steel, hardened and tempered. The shank is knurled to
provide grip. Punches are two types:
- Prick punch
- Centre punches.
Prick punch is sharply pointed tool used for marking small dots along the layout lines in order to
make them last longer. Centre punch has an angle more than obtuse and used to mark the centres
of holes to be drilled.
6.Try Square: It is made of steel and consists of a blade and a stock made in one piece set at
right angle to each other. It is used to test trueness of mutually perpendicular surfaces and for
making straight lines at right angle to each other.
Kavungya answered the question on
March 6, 2019 at 11:34