1. What is Lay out ?
Laying out is the planning of the work on the
surface of the material that is to be made
into the finished part. It is the scribing of
lines which indicates cuts to be made, the
centerlines of holes to be drilled, and other
details that guide the worker in completing
the job.
Bagerhat Technical
School & College.
2. Lay out tools
A scriber is a hand tool used in metalworking to mark lines on work
pieces, prior to machining. The process of using a scriber is called
scribing and is just part of the process of marking out. They are a rod
with a tip made of cast steel that has been hardened and tempered.
The point is sharpened to an angle of 30 or 40 degrees. Other tools
used to do layout work include precision squares, bevel
protractors, surface gages, height gages, scribers,
hermaphrodite calipers, dividers, prick punches, center
punches, hammers, V-blocks, parallels, angle plates, and a
variety of clamps.
Bagerhat Technical
School & College.
3. Center punch
A center punch is used to mark the centre
of a point. It is usually used to mark the
centre of a hole when drilling holes.
Bagerhat Technical
School & College.
4. Nail or Pin Punch :A nail punch also called a nail set, is used to drive
the head of a nail flush with or below a surface. A pin punch is a similar
tool used to drive pins for affixing a fixture to a rotating shaft. Nail and
pin punches have a body by which the punch is held, with a flat ended
cylindrical section whose diameter suits the object to be driven into the
wood.
DRIFT:A drift "punch" is misleadingly named; it is not
used as a punch in the traditional sense of the term. A drift
punch, or drift pin, or lineup punch, is used as an aid in
aligning bolt or rivet holes prior to inserting a fastener.
Bagerhat Technical
School & College.
5. Letter
stamps
Also known as letter stamps or number stamps. These are used to
emboss the impression of a letter or number into a work piece. They
are most common in the reverse image, this allows the end result to
be immediately readable, however they may be made as a positive
image. This is essential in the case of die or mold making and ensures
that the finished product will be readable, as a die is a negative image.
Bagerhat Technical
School & College.
6. A scriber block is used to layout lines at a set height from the base, thus its second
name surface height gauge or just "surface gauge".
The work piece is held against an angle plate so that it is perpendicular to the
surface plate , the scriber block is then adjusted to the required height and used to
scribe a line parallel with the table, by sliding the block along the table's surface.
Bagerhat Technical
School & College.
7. A surface plate is a solid, flat plate used as the main
horizontal reference plane for precision inspection, marking out
(layout), and tooling setup. The surface plate is often used as
the baseline for all measurements to the work piece, therefore
one primary surface is finished extremely flat with accuracy up
to 0.00001 in/0.00025 mm for a grade AA or AAA plate.
Surface plates are a very common tool in the manufacturing
industry and are often permanently attached to robotic type
inspection devices such as a coordinate-measuring machine .
surface plate
Bagerhat Technical
School & College.
8. V-block
V-Blocks are precision metalworking jigs typically used to hold
round metal rods or pipes for performing drilling or milling
operations. They consist of a rectangular steel or cast iron block
with a 90-degree channel rotated 45-degrees from the sides,
forming a V-shaped channel in the top. A small groove is cut in
the bottom of the "V". They often come with screw clamps to
hold the work. There are also versions with internal magnets for
magnetic work holding. V-blocks are usually sold in pairs.
Bagerhat Technical
School & College.
