A Concise note on
Workshop
Technology
Presented By:
NEPAL STUDENTS UNION
Purwanchal Campus Committee
Contact: Pawan Karki (072/BME)
->9844694276
->9815906780
( ONLY INTRODUCTION IS NECESSARY FOR THE FIRST YEAR WORKSHOP
COURSE)
HAMMERS AND ITS TYPES :
1.)BALL PIN HAMMER
2.) CLAW HAMMER
3.) CLUB HAMMER
4.) CROSS PIN HAMMER
5.) PIN HAMMER
6.) SLEDGE HAMMER
7.) WODDEN MALLET HAMMER
8.) RUBBER PLASTIC MALLET
HAMMER
IMPORTANT HAMMERS ARE EXPLAINED BELOW:
Different types of hammers:
1) Ball Peen Hammer: Those hammer which contain ball on it one part
of the head and the flat surface on one side. Mainly used in the work
with rivet.
2) Claw Hammer: those hammer which contain a claw on one side.
Used for taking out the nails and rivets which are fixed on certain
surface.
3) Cross Peen Hammer: Hammer with the pin, used for the works when
the acting surface area is small.
4) Wood Hammer: Hammer made up of wood, commonly used for the
sheet working.
5) Club Hammer: Hammer used for the heavy work, like in works
related with heavy metal, hard surface area.
OTHER IMPORTANT WORKSHOP TOOLS:
Fig. Various types of files
FILES: The files are the surface or the metal layer which I used to make any
surface smooth, free of rust. There are different types of files, some of them
are Flat file, Round file, semi round file, triangular file, square file etc. the
efficiency of different files are known by its pitch i.e. distance between the two
teeth.
Files are the most important hand tools used for the removal of materials.
They are made of hardened high carbon steel with a soft 'tang'. to which a
handle can be fixed. Files are categorised as follows:-
1) Length - measured from the shoulder to the tip.
2) Shape - the cross-sectional profile.
3) Grade - the spacing and pitch of the teeth.
4) Cut - the patterns of cutting edge.
5) Save Edge
6) There are no cutting edges on one side of the hand file. The purposes
for the save edge is to avoid the worker damage the work, when he is
filing a shoulder position.
Shape of Files
1. Hand File - The common file used for roughing and finishing. It is
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.
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 Figure 22f. Three Square File
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.
Grade
This refers to the pitch (spacing) of the teeth that spread throughout the whole
length of the file. Files with a rougher grade of cut give a faster metal removal
rate but a poorer surface finish or the vice versa. It should be noted that, for
the same grade of cut, a longer file would have a coarser pitch than a shorter
one.
The grades are as follows:
Bastard cut - medium teeth for general purposes, especially suitable for
mild steel.
Second cut - finer teeth for cutting hard metals.
Smooth cut - fine teeth for finishing.
Three grades of cut are in common use
Cut Pattern
i. Single Cut - There is only one set of cutting teeth to one edge. It gives a
less efficient cutting but a better finish. It is suitable for the soft metal.
ii. Double Cut - A double cut file has one set of teeth cut at 70 degrees to
one edge, and another set of grooves cut at 45 degrees to the other
edge. It is thus more efficient in cutting. It is easy to clog the teeth when
it is work on the soft metal.
iii. Rasp - Very coarse teeth, like the nail, it is commonly used for the cutting
off soft materials such as rubber, PVC, or wood etc.
Safety and Care of Files
a) Files teeth are brittle and therefore file should be placed properly and
should not be stacked on other tools..
b) New files should never be used on hard materials. E.g. castings or
welding.
c) Some brittle metal, e.g. brass is not readily filed with the worn teeth.
A new file should be used for these purposes and the file must be
kept in another stock.
d) Remove the pinning regularly by a file card/wire brush. Cutting is
carried on the forwardstroke.
e) It is very danger to use files without handles
Fig. Hacksaw
HACK-SAW: The hack-saw Is the device used for cutting propose, physically it
consist of hack saw frame , blade, handle etc., the blade are set on the frame
and the operation I carried out, the cutting Is done in forward stroke, and the
back stroke help to clean path for next stroke.
Fig. Rivets
RIVETS :Rivets are made up of oft metal which Is used to joint two or more
then plates or pieces of metals with each other fat and permanently, joint
made with rivets are called rivets joint. Mainly used in boiler, bridge etc.
Vernier Calipers
Vernier Calipers are more precise tools capable for measuring external
dimensions, internal dimensions, and depths. Besides the two pairs of
measuring jaws and the depth gauge, its main features also include a main
scale and a vernier scale.
The resolution of a vernier scale is determined by the difference on the
distance of one division on the main scale and one division on the vernier as
shown in figure 4. For example: A vernier scale of length 49mm is divided into
50 equal divisions.
That means ONE division on the vernier represents 49/50=0.98
mm while ONE division on the main scale represents 1mm.
Then, the resolution of the vernier is 1mm - 0.98mm = 0.02mm.
Introduction to Lathe:
Lathe machine:
A lathe is machine in which work piece is rotated against the cutting
tools. The cutting tool is moved lengthwise (parallel or at an angle),
crosswise (perpendicular or at angle) to the axis of the bed and the
shape of work generated depends upon the operation. The operation
are accomplished by holding the work securely and rigidly on the
machine and then turning it against cutting tool which removes metal
from the work in the form of clips. Turning, boring, thread cutting, etc.
are performed in lathe.
Main components of lathe:
1) Headstock
2) Carriage
3) Tailstock
4) Bed
Headstock
The main spindle mounted on bearing transmits the rotary motion to
work piece. The spindle that is securely mounted, is sturdy and of best
steel. In most cases the spindles are hollow. So that the bar stock can be
guided through. The bearing surfaces of the spindles are hardened and
ground plain bearings made of bronze are often used for spindles.
Rollers bearings have less friction and are also commonly used. The
spindle must run freely on the bearings. Too much play in bearings
causes chatter marks on the turned face of the work piece which may
also become oval.
The head of the main spindle is provided with threads for fixing all
kind of chucking equipment. Lathe centers can be inserted in the
tapered hole of the main spindle. The spindle is driven by the main drive
of the lathe.
Carriage
The carriage mainly supports and carries the turning tool and also
contains the feed mechanism and its adjustment. This carriage consists
of the saddle, the cross slide, the compound slide with tool holder and
apron. The slide should move in the guide ways freely without any play.
The saddle and the cross slide are either operated by feed shaft or
screw.
Tailstock
It serves as a support for turning long work pieces. For drilling and
reaming operations, the tailstock can be used as the tailstock sleeve that
has been provided with a mores taper to accommodate the respective
tools. The tailstock can be shifted on the lathe bed and can be clamped
in position through the base with a locking lever. The tailstock spindle
with hand wheel is used for shifting the tailstock sleeve. With the set
screw the sleeve can be clamped in position.
Lathe bed
It carries all lathe parts. It is supported by the pedestals. The carriage
and the tailstock move on the guide ways which are usually V and flat
shaped. Bigger diameters can be turned on the lathe with gap bed. It
consists of following parts: saddle, cross slide, compound slide, tool post
and apron.
Lab work on lathe:
We have known the operation and mechanism of lathe machine. We
used it for making hinge in lab. The lathe machine can be used for
various purposes such as straight turning, chamfering, shoulder turning,
facing, thread cutting filing, knurling, taper turning, polishing, grooving,
spinning, forming, drilling, reaming, boring, taping, grinding and milling.
Safety Measures:
1) The working area should be kept neat and clean.
2) If any accident happens, it should be reported to supervisor
immediately.
3) Files, scrapers etc. should not be used without handle.
4) It should be checked whether the machines and tools are in proper
condition or not before doing job.
5) Hair should be kept short or one should wear cap.
6) We should not play in the workshop.
7) Rings, watches, ties as well as college dress shouldnt be worn during
job.
8) Machine, equipment, tools should be kept clean and in good
condition.
9) The machine should be switched off immediately if anything goes
wrong.
10) We should wear safety glasses, shoes and apron during workshop.
IMAGES OF OTHER WORKSHOP TOOLS AND MACHINERIES:
1. LATHE MACHINE
2. HAND VICE
