Workshop Technology — Part 1 MCQs with Explanations

A slightly oxidizing flame is used in torch brazing of steel and cast iron. A stronger oxidizing flame is used in the welding of brass or bronze.

Gimlet is a small tool for boring holes, consisting of a shaft with a pointed screw at one end and a handle perpendicular to the shaft at the other

In TIG arc welding, The weld area and electrode is protected from oxidation or other atmospheric contamination by an inert shielding gas argon or helium

In sheet metal blanking, shear is provided on punches and dies so that Press load is reduced

The correct answer is (C) 46 mm . Here's why: In drawing operations, we start with a flat, round piece of metal (the blank) and form it into a desired shape, like a cup. To determine the initial blank size, we need to consider that the volume of material remains approximately constant during the drawing process. Imagine flattening out the cup. The area of that flattened-out material (the blank) must equal the surface area of the finished cup. A simplified way to estimate this for a cylindrical cup is: 1. Calculate the surface area of the cup (bottom circle + side wall). * Area of the bottom circle: π * (diameter/2)^2 = π * (25/2)^2 ≈ 490.87 mm 2 * Area of the side wall: π * diameter * height = π * 25 * 15 ≈ 1178.10 mm 2 * Total surface area ≈ 490.87 + 1178.10 = 1668.97 mm 2 2. Calculate the blank diameter : the area of the blank circle is equal to the total surface area of the cup. * Area of the blank circle = π * (diameter/2)^2 * π * (diameter/2)^2 = 1668.97 mm 2 * diameter/2= sqrt(1668.97/π) = 23.05 * diameter = 2 * 23.05 = 46.1 mm Therefore, the blank size is approximately 46 mm . In practice, a few more factors might influence the *exact* size (like material properties and thinning during drawing), but this gives a good estimate.

Option A: Hold the round bars during marking A scribing block is not meant to hold workpieces. Its design includes a heavy base and a scriber, but no clamping mechanism. For holding round bars, a V-block or other holding fixture is used. Therefore, this option is incorrect. Option B: Check the trueness of flat surfaces While a scribing block can be moved across a surface plate to detect variations in height, this is not its primary or most accurate function. Dedicated tools like surface plates, straight edges, or dial indicators are used to check the trueness of flat surfaces. Hence, this option is misleading and not correct in the context of its main purpose. Option C: Locate the centres of round bars This is the correct function. A scribing block, often used along with a V-block , is ideal for locating and marking the centre lines on cylindrical workpieces . By adjusting the scriber and rotating the bar, accurate centre marking can be achieved, which is essential for machining operations. Option D: Check the surface roughness Surface roughness is determined using roughness comparators or profilometers , not a scribing block. A scribing block has no capability to measure or compare the surface finish quality, so this option is incorrect. Conclusion: After evaluating all options, it is clear that the primary and correct use of a scribing block is to locate the centres of round bars . Therefore, the correct answer is Option C.

The cutting edge of a chisel should be Hardened and tempered A chisel is a tool with a characteristically shaped cutting edge of blade on its end, for carving or cutting a hard material such as wood, stone, or metal by hand, struck with a mallet, or mechanical power.

A welding torch head is used to weld metals those are difficult to weld by using electrode. It can be identified by having only one or two pipes running to the nozzle, no oxygen-blast trigger, and two valve knobs at the bottom of the handle letting the operator adjust the oxygen and fuel flow respectively. For gas welding, the pressure desired at the welding torch for acetylene is 7 to 103 kN/m 2 .

In metalworking, a fuller is a tool used to form metal when hot. The fuller has a rounded, either cylindrical or parabolic, nose and may either have a handle or a shank. The shank of the lower fuller allows the fuller to be inserted into the hardy hole of the anvil.

Ring gauge, is a cylindrical ring of a thermally stable material, often steel, whose inside diameter is finished to gauge tolerance and is used for checking the external diameter of a cylindrical object.

A lap joint or overlap joint is a joint in which the members overlap. Lap joints can be used to join wood, plastic, or metal. Lap joints are employed on plates having thickness Less than 3 mm

Thermit welding is a welding process that employs molten metal to permanently join the conductors. The process employs an exothermic reaction of a thermite composition to heat the metal, and requires no external source of heat or current. Thermit welding is often used in replacing broken gear teeth, repairing broken shears and joining rails, truck frames and locomotive frames etc.

Materials are limited to ductile materials because the threads are cold formed. . Also, materials with good deformation characteristics are necessary for rolling; these materials include softer (more ductile) metals and exclude brittle materials, such as cast iron.

Cope and Drag refer to the two halves (top and bottom, respectively) of a Pattern or Mold that is used in the Green Sand Casting Method.

Materials used. Typically, materials used for pattern making are wood, metal or plastics. Wax and Plaster of Paris are also used, Sugar pine is the most commonly used material for patterns, primarily because it is soft, light, and easy to work

A riser, also known as a feeder, is a reservoir built into a metal casting mold to prevent cavities due to shrinkage. Most metals are less dense as a liquid than as a solid so castings shrink upon cooling, which can leave a void at the last point to solidify.

Submerged arc welding (SAW) uses a pool of molten metal that is formed beneath a blanket of granular flux. The flux covers the arc and molten pool, preventing contamination from atmospheric gases like oxygen and nitrogen. This method provides deep penetration, high quality, and efficiency in welding thick materials. Carbon arc welding , TIG welding , and MIG welding also involve an arc, but they do not use the same submerged molten pool process as SAW. Hence, the welding method that uses a pool of molten metal is Submerged arc welding .

A casting defect which occurs due to improper venting of sand is known as Blow holes

The correct answer is (C) Steel. Here's why: What is a Riser? A riser is a reservoir of molten metal connected to the casting. Its main job is to compensate for shrinkage that happens as the metal cools and solidifies. Why different materials need different sized risers: Different metals shrink by different amounts when they cool down from liquid to solid. The greater the shrinkage, the bigger the riser needs to be to feed the casting and prevent voids (holes) from forming inside. Why Steel needs the biggest riser: Steel has the highest shrinkage rate among the given options (Aluminum, Cast Iron, Copper). This means it shrinks the most when it solidifies. Cast iron actually expands slightly during solidification, making it need the smallest riser. Aluminum and Copper shrink, but less than steel, so they require risers smaller than steel's. In short: Because steel shrinks the most as it solidifies, it needs the largest riser to supply enough extra metal to prevent defects in the final casting.

A hacksaw blade is primarily identified and ordered by its length. Think of it like buying a piece of wood – you need to know how long it is! Here's why the other options are less important for initial specification: Option B: Material: While the material (like high-speed steel) is important for performance, it's usually a secondary specification. Option C: Width: The width is generally standardized, and not the first thing you'd use to specify a blade. Option D: Number of teeth: The number of teeth (or TPI - Teeth Per Inch) is also important for the type of material you're cutting, but again, length is the primary identifier. So, when you go to buy a hacksaw blade, you'd typically ask for a "12-inch blade" (length) first, then specify the type of material and TPI depending on your needs.

The welding process used in joining mild steel shanks to high speed drills is Flash butt welding

For cutting brass, the hacksaw blade should have 14 teeth per 25 mm.

Arc welding is a fusion welding process where heat is generated to melt and join metals. The electric arc is created between the electrode and the workpiece, which produces intense heat. Voltage is responsible for initiating and maintaining the arc gap between the electrode and the workpiece. Flow of current provides the energy required to sustain the arc and generate heat for melting the metal. Contact resistance at the point of initial contact helps in momentarily generating heat, which assists in the arc initiation. Therefore, all these factors — voltage, current flow, and contact resistance — contribute to producing the electric arc in arc welding. Hence, the correct answer is Option D: All of these.

A file removes the metal during Forward stroke

Lancing is the operation of Cutting a sheet of metal through part of its length and then bending the cut portion.

Notching is the operation of Removal of metal to the desired shape from the edge of a plate

Upper Limit = 20.000 + 0.035 = 20.035 Lower limit = 20.000 - 0.025 = 19.975 Tolerance = Upper Limit - Lower limit = 20.035 - 19.975 = 0.06

In forehand welding, the weld is made From right to left

A diamond pointed chisel is used for cutting V-shaped grooves

Spot welding is used for welding Lap joints in plates having 0.025 mm to 1.25 mm thickness

Thermit which is used in Thermit welding is a mixture of Iron oxide and aluminium

For smoothing and cleaning out depressions in the mould a Lifter is used. A slick is used for repair and finishing the mould surface after the removal of pattern. It is a double ended tool having a spoon on one end and a flat on the other end. A lifter is used for picking up the unwanted dust and damaged parts of the mould. It is a L- shaped steel tool with long holding shank and a small toe. It is available in thin sections of various width and lengths, according to the shape of the mould. A swab is used for moistening the sand around the edge before the pattern is withdrawn. It consists of soft hair brush to hold water at one end, and a rubber build at the other end. A gagger is used for reinforcing the moulding sand in the cope part of the moulding box. These are the iron rods or thick wires bent at one or both the ends. The bottom end of the gagger must be kept 5 to 8 mm away from the embedded pattern.

In order to produce uniform packing of sand in the moulds a Sand slinger is used.

In a squeeze machine, there is a squeezer head or a plate which is used as a pressing board to force the sand inside or compress it. This machine is mostly used for shallow patterns. These machines are classified as, squeeze machine, sand slinger, jolt-squeeze machine and sand slinger.

When a hole or cavity to be cored is not in line with the parting surface, then a drop core is used.

In casting, a sprue is the passage through which a molten material is introduced into a mold, and the term also refers to the excess material which solidifies in the sprue passage. In sand casting, the sprue is formed by a dowel, which is removed from the sand to make the hole into which the metal is poured.

In welding magnesium with TIG arc welding, direct current with Reversed polarity is used The preferred polarity of the GTAW system depends largely on the type of metal being welded.

For welding plates of thickness more than 12.5 mm, its edges Should have a double-V or U-groove on both sides

A rip saw is a wood saw that is specially designed for making a rip cut, a cut made parallel to the direction of the wood grain.

A jolt machine is used to Ram the sand harder at the pattern face with decreasing hardness towards the back of the mould