WORKSHOP HAND TOOLS:
LIST OF WORKSHOP TOOLS
1. BENCH VICE:
It is the most commonly used vice sometimes also known as parallel jaw vice. It essentially consists of a cast steel body, a movable jaw, a fixed jaw, both made of cast steel, a handle, a square threaded screw and a nut all made of mild steel. A separate cast steel plates known as jaw plates with teeth are fixed to the jaws by means of set screws and they can be replaced when worn. The movement of the vice is caused by the screw which passes through the nut fixed under the movable jaw. The screw is provided with a collar inside to prevent it from coming out and handle at the outer end. The width of the jaws suitable for common work varies from 80 to 140 mm and the maximum opening being 95 to 180 mm.
2. WOODWORKING VICE
Woodworking vices are specifically used to clamp wood, not metal. Woodworking vices differ from metalworking vices as they are usually designed to mount underneath a workbench. These vices also have smoother jaws than metalworking vices, so as not to damage the surfaces of wooden objects when clamping. They too are available in a variety of different sizes and models.
3. PIPE VICE
Pipe vices are a plumber's tool, often used to hold pipes in place for threading and cutting. There are two main styles: chain and yoke. The yoke type vice uses a screw to clamp down the pipe and the chain style uses a chain for securing the pipe.
4. PIN VICE
Pin vice is used for holding round jobs of small diameter such as wire and pins, during working. It also forms a very useful handle for small files. It consists of a handle and a tapered nose covering a small collet chuck at its end. The chuck carries the jaws which are operated by turning the handle.
5. SPANNERS AND WRENCHES
A spanner or wrench is used for turning a nut, bolt or similar fixing that is turned to tighten. The spanner is used to grip the given fixing a nut/ bolt and turn it, allowing you to apply torque and tighten the nut onto the bolt.
They are generally made from drop forged steel and coated in chrome to stop corrosion. Higher quality spanners tend to be made from Chromium-Vanadium alloys and in some cases even titanium.
Screwdrivers have three main parts: the handle, which is gripped by the user; the shank, which is the steel portion extending from the handle; and the blade, which is the end that fitsinto the slot of the screw. Several types of screwdrivers are shown in Figure.
TYPES OF SCREW DRIVERS.
The standard screwdriver is used for most ordinary work and comes in a variety of sizes. The blade must have sharp corners and fit the slot in the screw closely; otherwise it is likely to slip and damage the slot. It is also important that a screwdriver be held firmly against the screw to prevent it from slipping and injuring the worker or the work.
The offset screwdriver makes work possible in tight corners where the straight type will not enter. It has one blade forged in line with the shank, and the other blade at right angles to the shank. With such an arrangement, first one end of the screwdriver can be used and then the other, changing ends after each swing, thus working the screw in or out of the threaded hole.
The Phillips-type screwdriver is made with a specially shaped blade to fit Phillips-type cross-slot screws. The heads of these screws have two slots that cross in the center. This checks the tendency of the screwdriver to slide out of the slot onto the finished surface of the work.
The ratchet screwdriver is used to drive or remove small screws rapidly. Some screwdrivers have handles made of insulating material, and are useful when electrical work is being done. When a screwdriver with an insulated handle is not available, the handles of other screwdrivers can be insulated by wrapping them with tape.
7. Try Square
It is better known as engineer’s try square and is a very common tool used for scribing straight lines at right angles to a true surface or testing the trueness of mutually normal surfaces. They are made in different sizes from the steel pieces. It consists of a steel blade fitted into a steel stock of rectangular cross-section. They are well hardened and tempered to suit the need. Both inner and outer surface of the blade are kept truly at right angles to the corresponding surfaces of the stock.
8. COMBINATION SET
The combination square set (also simply called a “combination set”) is a measuring tool which is designed primarily for measuring angles and lengths. It is used by people working in a number of different trades, including woodworkers and engineers.
10. Surface Gauge
It consists of a cast base, perfectly planed at the top, bottom and all sides. Two guide pins are provided at the rear end of the base which can be pressed down to project below the base. These pins can be used against the edge of the surface plate or any other finished surface for guiding the instrument during scribing.
A swivel bolt is provided at the top of the base in which the spindle is fitted. This spindle can be swung and locked in any desired position by means of the adjusting screw. The scriber is fitted in an adjustable screw on the spindle and is capable of being adjusted at any inclination and height along the spindle. A rocker is provided at the top of the base and it carries an adjusting screw at its rear end.
10. UNIVERSAL MARKING SURFACE GAUGE
It is an improved variety of the surface gauge simple scribing block. It is designed in such as way that appreciably finer adjustments can be made very quickly. It consists of a cast base perfectly machined and ground at the top, bottom and all sides. The base of the gauge usually carries a V-shaped slot at the bottom so as to render it suitable for use on round objects. This gauge is commonly employed for scribing parallel lines at desired heights from a plane surface, comparing the trueness of two similar heights, setting out a desired height and similar other operations, and forms an indispensable instrument of bench work.
Several types of punches are shown in Fig. 12. These tools may be used for a variety of jobs, but the correct punch for the job should always be selected.
A center punch is used to make a starting mark for a drill when holes are to be drilled in metal. If the center punch mark is not made, the drill will wander or "walk away" from the desired center.
The center punch point should be taper-ground to an angle of about 90°. Never use a center punch to remove a bolt or pin, as the sharp point will act as a wedge and tend to tighten the bolt or pin in the hole.
Prick punches are generally used for marking centers and lines in layout work.
Starting punches, sometimes called drifts, have a long taper from the tip to the body. They are made that way to withstand the shock of heavy blows. They may be used for knocking out rivets after their heads have been cut off, or for freeing pins or bolts from their holes. To start a bolt or pin that is extremely tight, use a starting punch that has a point diameter only slightly smaller than the diameter of the object that is being removed.
After a pin or bolt has been loosened or partially driven out, it may be found that the starting punch is too large to finish the job. A pin punch can then be used, as it is designed to follow through the hole without jamming. Both starting punches and pin punches must have flat ends, never edged or rounded ones.
13. SURFACE PLATE
Its specific use is in testing the trueness of a finished surface, testing a try square, providing adequate bearing surface for V-block and angle plates, etc., in scribing work.
It is a cast iron plate having a square or rectangular top perfectly planed true and square with adjacent machined faces. The top is finished true by means of grinding and scrapping. This plate carries a cast iron base under it and the bottom surface of the base is also machined true to keep the top surface of the plate in a perfect horizontal plane.
14. STEEL RULE
A steel rule is a simple measuring instrument that is used for measuring distances and ruling straight lines. It is used in diverse fields, such as geometry, technical drawing, engineering and construction.
The steel rule is a very common measuring tool. According to the Encyclopedia of Alternative Energy, flat steels rule are generally 6 or 12 inches long. These steel rules can either be flexible or rigid; their widths determine the accuracy of measurement.
A steel rule is used in geometry, technical drawing, engineering and building to measure distances and rule straight lines.
15. V -Block
A ‘V” block serves as a very useful support to the work in marking. It usually works in conjunction with a U-clamp.
Round bar is placed longitudinally in the block and the screw in the clamp tightened. Its specific use is in holding the round bars during marking and center drilling their end faces, which are to be held between centers on the lathe. Also it is very suitable for holding round bars in drilling operations when the axis of the drill is to be kept normal to the axis of the bar.
Vernier caliper, which is commonly used to measure accurately
(1) outside diameters of shafts,
(2) thicknesses of various parts,
(3) diameters of holes or rings and
(4) internal dimensions of hollow jobs or articles.
It works on the principle of vernier and can measure the dimensions to an accuracy of 0.02 mm. For making a measurement of external dimensions, the job is placed between the 376 ntroduction to Basic Manufacturing Processes and Workshop Technology fixed and the movable jaws. The movable or the sliding jaw is moved until it almost contacts the job kept against the fixed jaw. The sliding jaw assembly of the vernier caliper that carries the fine adjustment screw should be clamped to the graduated beam with the help of adjustment clamp. The two jaws are then brought into contact with the job by moving the sliding jaw with the help of fine adjustment screw. The jaws should make now definite contact with the job but should not be tight. The main slide assembly is then locked to the beam with help of clamp. The caliper is then carefully removed from the job to prevent springing the jaws and the reading is taken. For making a measurement of internal dimensions, the job is placed outward between the fixed and the movable jaws meant for measuring inner dimension.
The micrometers are commonly employed for measuring small dimensions with extreme accuracy of 0.01 mm. They may be of the three kinds
(a) External micrometer for measuring external dimensions,
(b) Internal micrometer for measuring internal dimensions, and
(c) Depth micrometer for measuring depths.
For measuring a dimension in external micrometer, the work piece is held between the fixed anvil face and the spindle face of the micrometer. The spindle of the micrometer is allowed to move linearly towards the work by rotating thimble. When the spindle will touch the work piece properly, the ratchet will give its sound. The small locking lever is then rotated to clamp the spindle so that reading can be taken more accurately. Outside micrometers are used for measuring the outside dimensions of jobs, such as diameter of a bar, rod and thickness of plate. Generally, until and unless they are provided with the vernier attachment, the former can read up to 1/1000 or 0.001 inch and the latter up to 0.01 mm. The former are known as inches micrometers and the latter metric micrometers, which are gradually replacing the former due to the introduction or adopting of metric system.
18. VERNIER HEIGHT GAUGE
Fig. 19.20 illustrates the vernier height gauge, which is employed for measuring the height of parts and in precision marking work. It consists of a heavy base, an accurately finished bottom, a vertical bar mounted square to the base, carrying the main scale, a sliding head with vernier, an auxiliary head with fine adjustment screw and nut and a bracket attached to the sliding head. This bracket is provided with a clamp by means of which interchangeable jaws can be fixed over there. The jaws can be fixed for measuring height or replaced by scribing jaws according to requirement or need.
Divider, instrument for measuring, transferring, or marking off distances, consisting of two straight adjustable legs hinged together and ending in sharp points. It is used principally in drafting for the accurate transfer of dimensions from a measuring scale and in machine shops for scribing lines on surfaces, usually machined, with dimensions taken from a ruler.
Calipers are generally of two types inside and outside to make internal or external
measurements. They do not have direct scale reading. They transfer the measurement from
jobs to scale or vice versa. Fig. 19.16 shows a simple outside caliper. The caliper is held in
a rule as shown in Fig. 19.17 to read the size. It is used to make external measurement such
as thickness of plates, diameter of rods.
Several commonly used types of pliers are shown in Fig. 7.
FIG. 7. TYPES OF PLIERS.
Side-cutting pliers are used principally for holding and bending thin material or for cutting wire. Adjustable combination pliers have a slip joint that permits the jaws to be opened wider at the
hinge for gripping large diameters. They are used principally for holding and bending flat or round stock. The various lengths and shapes of flat-nose, round-nose, and needle-nose or long-nose pliers make it possible to bend or form metal into a variety of shapes, to hold objects in tight spots, and to make delicate adjustments. Needle-nose pliers are helpful when recovering a washer or nut from a place where it is hard to reach. They also make it easier to remove and install such things as valve-spring retainer pins. They are not of heavy construction, however, and should not be forced beyond their capacity. Their jaws are comparatively weak, and are easily broken or sprung.
Avoid using pliers on a hardened surface, as such use dulls the teeth and causes pliers to lose their gripping power. Do not use pliers for loosening or tightening nuts, as the flats of the nuts will become damaged.
Diagonal-cutting pliers have short jaws with blades at a slight angle, as shown in Fig. 8. This tool is valuable when removing and replacing cotter pins, and can be used not only to cut the
FIG. 8. DIAGONAL-CUTTING PLIERS.
pins to the desired length but to spread the ends after the pins are in place. They are also handy for cutting the soft wire which is passed through small holes in nuts and bolt heads to "safety" them, or prevent them from working loose. When diagonal-cutting pliers are used, the cut should be made with the throat of the jaws, not with the points, as the latter use would increase the tendency to spring the jaws apart. Once the jaws are sprung, it is difficult to cut fine wire.
22. FEELER GAUGE
A feeler gauge is a tool used to measure gap widths. Feeler gauges are mostly used in engineering to measure the clearance between two parts. They consist of a number of small lengths of steel of different thicknesses with measurements marked on each piece.
Feeler gauge available in no. of the blade like 10,13,20 and 28. With a step of 0.05 and 0.10 mm. The thicknesses of the blades are in fractions of mm and inches, usually ranging from 0.03 mm to 1mm.
23. PITCH GAUGE:
Pitch Gauge is a effective and fairly accurate instrument used to identify or check the pitch of the threads cut on different threaded items. It consists of a case made of metal carrying a large number of blades or threaded strips which have teeth of different pitches, cut on their edges and markings corresponding to these pitches on their surfaces. This gauge can be commonly used to measure or check the pitches of both external and internal threads.
24. WIRE GAUGE
Wire gauge is a measurement of a wire, either its diameter or cross-sectional area. The gauge of a wire determines how much current can flow through the wire. The gauge also determines the resistance of the wire and its weight per unit of length.
Desired lengths of bar stocks, rods, tubes, iron flats and metal sheets, etc. are always required to be cut in fitting shop. Hack-saw is a common tool used for this purpose. It consists of a metal frame, fitted with a wooden handle, carrying metal clips with wing-nut at its end to hold. The clip carrying the wing nut is threaded so as to stretch the blade to the desired extent. The frame can be either of fixed type, which can accommodate the same length of blades or adjustable type which is capable of accommodating different lengths of blades.
Hack saw blades are made of high carbon steel or low alloy steel. Hack saw blade is the main part. Push type blades, those which cut in forward stroke only, are generally used. In these, the teeth always point away from the operator. The blades in common use are generally 0.7 mm thick, 12.7 mm wide and 20 cm to 30 long. About 5 to 7 teeth per cm length of blade from the course group and 8 to 12 teeth per cm from the fine group of teeth.
sphere and cylinders. Fig. 19.18 shows the standard spring
joint outside caliper.
Files of different types are the principal hand tools used by a fitter. All the files, irrespective of their shape, size and grade, essentially consist of two main parts, viz., a toothed blade and a pointed tang, which is fitted in a handle. Files are generally forged out of high carbon steel, followed by cutting of teeth, hardening and tempering etc. Common shapes of the files available are flat, hand, square, pillar, round, half round, triangular, knife edge, etc.
These files are manufactured in different varieties and their classification is governed by the following factors: effective length- i.e. excluding the length of tang, shape or form of the cross-section, depth, spacing and cut of teeth
Length of the files varies according to the need but the most commonly used lengths range from 10 cm to 30 cm and they cover almost all sorts of filing work done by hand.
Length between 10 cm and 15 cm are generally used for fine work, between 15 cm and 25 cm for medium sized work and above 25 cm for all general and large sized jobs.
Square file which carried double cut teeth on all the four faces and is normally made tapered for about one-third of its length near the end opposite to the tang.
Triangular file which normally carries single cut teeth on all the faces and is made tapered towards the end for about two-third of its length near the tip. The cross-section is an equilateral triangle.
There are many verities of chisels used for chipping work by a fitter. Some very commonly used forms are Flat, Cross-cut, Round nose and Diamond point.
All the chisels are forged from bar stock of carbon steel, to the desired shape and the cutting edge ground to the correct angle.
The forging operation is followed by annealing, hardening and tempering to make chisel body tough and obtain a sharp cutting edge.
Full length of the chisel is never hardened, only a small length about the cutting edge (say about 20 to 30 mm) is hardened.
A flat chisel is a general purpose chisel which is most widely used in cutting work, chipping large surface, cutting metal sheets, rods, bar stocks and similar other purposes. Since it cuts the metal in cold state it is also frequently known as cold chisel.
A round nose chisel is used for drawing the eccentric hold back to correct centre which has run off-centre during drilling operation. Another specific use of this type of chisel is in cutting oil grooves and channels in bearings and pulley bushes and cleaning small round corners.
A cross cut is a comparatively narrow chisel having its cutting edge slightly broader than the blade. It is made to keep the blade free when the chisel is used to cut deep groove into the metal. Normal widths of the cutting edge vary from 3 mm to 12 mm. This chisel is used to cut parallel grooves on large surfaces, before chipping by means of a flat chisel, cutting key ways, etc.
A diamond point chisel is a special purpose chisel used for chipping rough plates and cutting cast iron pipes, cutting ‘V’ grooves, chipping sharp corners, squaring up corners of previously cut slots and cleaning angles.
The hammer is one of the most widely used fitter’s tools. It is used for striking chisels in chipping and cutting and the punch in marking.
All the hammers used in a fitting shop are similar in construction to the smith’s hand hammers, such as ball peen, cross peen, straight peen, etc. The only difference lies in weight. Hammers used in fitting work are comparatively lighter in weight than the smith’s hand hammers. They normally weigh from 0.45 kg to 0.7 kg.
Ball peen hammer is the most commonly used hammer. The peen is ball shaped. It is used for riveting, chipping, drawing and laying out. The weight of the hammer varies from 0.11 to 0.91 kg (as per IS standards).
Fig. 2.8 Hammers
Cross peen hammer resembles the ball peen hammer in shape except that its peen is in wedge shape and at right angles to the eye. This hammer is used for bending and hammering in the corners.
Straight peen hammer has a peen in line with the handle and is used for peening or stretching the metal.