Question 1

Manufacturing terminology — exterior blends Which term denotes a rounded exterior blend between two surfaces on a part drawing or CAD model?

Accepted Answer

Introduction / Context: Engineering drawings distinguish between interior and exterior corner treatments to avoid ambiguity in fabrication and inspection. Two of the most common are fillets and rounds, which reduce stress concentrations and improve handling and aesthetics. Given Data / Assumptions: We are asked specifically about an exterior blend. Standard drafting conventions apply (ASME Y14 series). The options include fillet, round, taper, and chamfer. Concept / Approach: A round is a radius applied to an outside (convex) corner. A fillet is an inside (concave) corner radius. A chamfer removes material at a straight angle rather than a curve. A taper gradually changes thickness or diameter along a length. Correct terminology helps machinists select the right tools and inspectors apply correct gauges and tolerances. Step-by-Step Solution: Identify the corner condition: exterior.Match the term: “round” equals exterior radius; “fillet” equals interior radius.Conclude that “Round” is correct. Verification / Alternative check: Check CAD features: many systems label exterior edge blends as “Round” and interior ones as “Fillet,” although some software uses “Edge Blend” generally; drafting notes maintain this distinction for clarity. Why Other Options Are Wrong: Fillet: interior, not exterior. Chamfer: straight bevel, not curved blend. Taper: longitudinal change in section, not a corner treatment. Common Pitfalls: Omitting the radius value; always specify size (for example, R3). Mixing “round” and “edge break”; an edge break may be small and unspecified, whereas a round is dimensioned. Final Answer: Round

Question 2

Preventing rotation on shafts — attachment features Which combination is commonly used to attach parts to a cylindrical shaft so they do not rotate relative to it?

Accepted Answer

Introduction / Context: Rotary power transmission often requires positive mechanical engagement between a shaft and a hub (gear, pulley, or coupling). Designers choose features that prevent slip under torque while enabling assembly, disassembly, and alignment. Given Data / Assumptions: The part must not turn on the shaft. Standard machine elements are considered. Terminology: keyway (groove in hub), keyseat (groove in shaft), key (inserted element). Concept / Approach: A key transmits torque by bearing shear and compressive forces between the shaft keyseat and hub keyway. This positive drive is common, standardized, and easy to service. Alternatives include splines for higher torque or precision timing applications and interference fits plus set screws for light duty. Knurls increase friction, not positive drive. Bearings support rotation; they do not lock components to the shaft. Step-by-Step Solution: Identify the requirement: prevent relative rotation.Select the standard solution: key + keyseat/keyway interface.Confirm suitability across common applications (pulleys, gears, couplings). Verification / Alternative check: Review machine design texts: keys and keyways are fundamental for torque transmission with standardized sizes (for example, Woodruff, square, or rectangular keys) per standards like ISO or ANSI. Why Other Options Are Wrong: Lugs and bearings: lugs are attachment bosses; bearings permit rotation, not prevent it. Keyseats and bearings: bears same flaw—bearings allow rotation. Knurls and keys: knurling alone does not provide positive drive; the essential pair is key with keyway/keyseat. Common Pitfalls: Failing to specify fit, length, and material for the key, leading to fretting or failure. Relying only on set screws for high-torque applications. Final Answer: Keys and keyways/keyseats

Question 3

Hole features — naming the conical recess What is the correct term for a conical-shaped recess around a hole, most often used to seat a flat or oval head (tapered) screw flush with a surface?

Accepted Answer

Introduction / Context: Mechanical drawings specify hole features to accommodate different fastener head forms and functional needs. Correctly distinguishing between counterbore, countersink, spotface, and boss ensures that the part is machined and assembled as intended. Given Data / Assumptions: The recess is conical in shape. It is used to receive a tapered screw head so that it sits flush or slightly below the surface. Standard drafting and machining terminology is used. Concept / Approach: A countersink is a conical recess, typically at standard included angles (for example, 82 degrees or 90 degrees depending on regional standards). A counterbore is a cylindrical, flat-bottom enlargement for socket head cap screws. A spotface lightly faces a small circular area to create a flat seating surface. A boss is a protruding cylindrical feature, not a recess. Step-by-Step Solution: Identify the shape: conical indicates countersink, not counterbore or spotface.Match to usage: tapered screw heads require a conical seat.Select the correct term: countersink. Verification / Alternative check: Compare standard hole callouts: “Ø6 CSK 82° for flat head screw” denotes countersink; “Ø6 C’BORE Ø10 x 5 deep” denotes counterbore—clearly different geometries and tools. Why Other Options Are Wrong: Boss: protrusion, not a recess. Spotface: shallow facing for flatness, not conical. Counterbore: cylindrical enlargement with flat bottom. Common Pitfalls: Specifying the wrong angle for the fastener standard, leading to poor seating or damage. Confusing countersink symbols with counterbore symbols in CAD annotations. Final Answer: Countersink

Question 4

Edge treatments on cylindrical parts — ease of handling and assembly Which term describes an angled surface applied to the end edge of a cylinder to remove the sharp corner and make handling or insertion easier?

Accepted Answer

Introduction / Context: Edges on cylindrical parts are often modified to improve safety, assembly, and performance. Selecting the correct term ensures machinists apply the intended geometry and inspectors verify the correct feature. Given Data / Assumptions: The feature is applied at an edge to ease handling or insertion. The modified surface is angled, not curved. The context is standard mechanical drafting terminology. Concept / Approach: A chamfer removes the sharp edge by cutting at a specified angle and length (for example, 1 x 45 degrees). It is common at the ends of shafts for easier bearing insertion or to prevent burrs from interfering with assembly. A fillet creates a curved interior corner; a round would be the exterior curved corner. A taper changes diameter gradually along a length, not just an edge. A lug is a protruding tab used for attachment, unrelated to edge treatment. Step-by-Step Solution: Confirm the geometry: angled edge removal.Match to term: chamfer equals angled edge treatment.Conclude the correct term is “Chamfer.” Verification / Alternative check: Typical callouts like “CHAMFER 0.5 x 45°” appear on shaft ends and holes for lead-in; CAD tools include chamfer features to create this geometry quickly and consistently. Why Other Options Are Wrong: Fillet: interior curve, not an angled edge. Taper: long gradual diameter change. Lug: protruding attachment tab. Common Pitfalls: Failing to specify both size and angle, causing ambiguity in manufacturing. Using a round when clearance requires a straight chamfer. Final Answer: Chamfer

Question 5

Attachment features — identifying protrusions Which term refers to a flat or rounded tab that protrudes from a surface, usually provided to allow attachment by bolts or other fasteners?

Accepted Answer

Introduction / Context: Designers often add localized protrusions to enable mounting, lifting, or alignment. Using precise terminology on drawings prevents confusion during casting, machining, and assembly, and guides inspectors on acceptance criteria. Given Data / Assumptions: The feature is a protruding tab intended for attachment. It may be flat or rounded in plan. Common alternatives include bosses and pads with different purposes. Concept / Approach: A lug is a protruding tab, frequently with holes or slots for fastening. A boss is a raised cylindrical feature, typically used to reinforce a hole, provide a bearing surface, or accept a fastener or insert. A chamfer is an edge modification, while a spotface is a shallow facing operation to create a flat seating surface around a hole. The description given matches “lug.” Step-by-Step Solution: Identify intended use: provide a place for attachment hardware.Match geometry: protruding tab on the exterior is a lug.Confirm that other terms do not describe tabs for attachment. Verification / Alternative check: Inspect casting and forging drawings: lugs are common for lifting eyes, hinge points, and bracket attachments, while bosses are circular and often centered on holes to thicken material locally. Why Other Options Are Wrong: Boss: typically cylindrical and centered on a hole for reinforcement rather than a tab. Chamfer: edge bevel, not a protrusion. Spotface: small machined flat around a hole, not a protruding tab. Common Pitfalls: Using “boss” and “lug” interchangeably; shape and purpose differ and affect machining and tooling. Failing to specify thickness and hole details on the lug, leading to inadequate strength. Final Answer: Lug

Question 6

Machine elements — protective sleeves and guides Which term denotes a hollow cylindrical component commonly used as a protective sleeve, guide, or plain bearing between a shaft and housing?

Accepted Answer

Introduction / Context: Rotating assemblies often include a sacrificial or replaceable element that provides low-cost wear resistance and guidance between two components. Identifying and specifying this element correctly is essential for reliable operation and maintainability. Given Data / Assumptions: The part is hollow and cylindrical. It functions as a sleeve, guide, or bearing surface. Typical applications include shafts rotating in housings with moderate loads and speeds. Concept / Approach: A bushing (also called a plain bearing or sleeve bearing) is a cylindrical insert that reduces friction and wear. Materials include bronze, PTFE-lined composites, polymers, or sintered metals. Bushings are inexpensive, compact, and often self-lubricating. A lug is a protruding tab for attachment, a chamfer is an edge bevel, and a knurl is a surface texture to improve grip or press-fit retention. Step-by-Step Solution: Identify geometry and function: hollow cylinder acting as sleeve/bearing.Map to standard machine element terminology: bushing/plain bearing.Select “Bushing.” Verification / Alternative check: Consult component catalogs; bushings are specified by ID, OD, length, and material, with options like flanged ends or lubrication grooves, confirming the definition and usage. Why Other Options Are Wrong: Lug: attachment tab, not a sleeve. Chamfer: edge feature. Knurl: surface pattern, not a separate component. Common Pitfalls: Confusing bushings with bearings with rolling elements; bushings are plain bearings without balls or rollers. Neglecting lubrication or material compatibility, leading to premature wear. Final Answer: Bushing

Question 7

Terminology check in 2D representation: Is a keyway a circumferential groove cut around the diameter of a shaft, often where it changes diameter, or is that description incorrect for a keyway?

Accepted Answer

Introduction / Context: Mechanical drawings rely on precise terms. A keyway is an axial slot cut along a shaft to accept a key that prevents relative rotation between the shaft and a mating hub. A circumferential groove around a change in diameter is a different feature (e.g., relief/undercut), not a keyway. Given Data / Assumptions: Keys fit into keyways to transmit torque. Keyways run longitudinally (axially) along the shaft surface. Circumferential grooves serve other purposes (stress relief, snap-ring seats). Concept / Approach: Map function to geometry. Torque transmission requires an axial slot aligning with the hub keyseat. A groove around the diameter does not locate a rectangular key and does not serve the locking function of a keyway. Step-by-Step Solution: Identify the required geometry for a key/keyway pair (axial slot).Contrast with a circumferential groove (encircles shaft, different function).Conclude the statement equating a circumferential groove to a keyway is incorrect. Verification / Alternative check: Standards for keys/keyways specify width, depth, and axial position; relief grooves and snap-ring grooves have distinct standardized callouts. Why Other Options Are Wrong: References to tapered shafts, Woodruff keys, or fillet reliefs do not convert a circumferential groove into a keyway. Common Pitfalls: Confusing undercuts or ring grooves with keyways; misdimensioning orientation (axial vs circumferential). Final Answer: Incorrect

Question 8

Conventions for small blends: Are “runouts” used as small curves to depict how fillets blend into plane surfaces that are tangent to cylinders in orthographic views?

Accepted Answer

Introduction / Context: Orthographic drawings use conventional breaks and runouts to show how curved features such as fillets and rounds blend into adjacent surfaces. A runout is a short curved transition indicating the smooth tangential merge of a radius into a plane or another curved surface, improving readability without over-detailing. Given Data / Assumptions: Fillets/rounds are tangential transitions, not sharp intersections. Orthographic projection simplifies depiction using conventions. Runouts shorten and clarify the representation at edges. Concept / Approach: Use runouts to visually indicate continuation of curvature where a full geometric construction would clutter the view. This matches drafting standards that favor clarity while preserving intent about tangency and blend. Step-by-Step Solution: Locate the fillet where a cylindrical surface meets a plane.Sketch a small curved runout to show how the fillet meets the plane tangentially.Avoid excessive arc construction lines; keep the cue compact.Annotate radius if necessary in dimensions/notes. Verification / Alternative check: Compare with detailed CAD sections; the physical blend is smooth. The runout convention communicates this efficiently in 2D views. Why Other Options Are Wrong: Limiting runouts to chamfers, perspective, or isometric sketches misstates their orthographic drafting role. Common Pitfalls: Overdrawing the runout or misplacing it so it implies a non-tangent junction; omitting necessary radius callouts elsewhere. Final Answer: Correct

Question 9

Sheet layout reality: Is it true that, due to space and clarity constraints, it is not always possible to keep every orthographic view strictly aligned on a single drawing sheet?

Accepted Answer

Introduction / Context: Orthographic projection emphasizes alignment: top above front, right side to the right, etc. In practice, crowded sheets, scale limitations, and additional views (auxiliary, sections, details) may force deviations while maintaining clarity and correct dimensioning. This item probes practical layout awareness. Given Data / Assumptions: Standard alignment is preferred for comprehension. Sheets have finite space; scale and view count vary. Clarity and readability override rigid alignment when necessary. Concept / Approach: Apply the hierarchy: correctness and clarity first, conventions second when they conflict. Additional arrows, labels, and view references can preserve intent if strict alignment cannot be maintained due to constraints. Step-by-Step Solution: Lay out principal views at suitable scale.Add auxiliary/section/detail views as needed.If space prevents strict alignment, place views logically and reference them clearly.Maintain consistent dimensions, datums, and identifiers. Verification / Alternative check: Check that centerlines, projection symbols, and view labels remove ambiguity even when a view is shifted. Peer review for readability confirms adequacy. Why Other Options Are Wrong: Restricting the statement to specific view types ignores the broader layout challenge across disciplines. Common Pitfalls: Breaking alignment without adequate references; scaling views inconsistently; overcrowding a single sheet when multiple sheets would be clearer. Final Answer: Correct

Question 10

Handed parts: Are right-hand and left-hand parts mirror images that are intended to be interchangeable, or are they opposite-handed and therefore not interchangeable?

Accepted Answer

Introduction / Context: Handedness describes mirror-image counterparts (right-hand vs left-hand) in parts such as threads, levers, brackets, and housings. Recognizing that handed parts are not interchangeable prevents assembly errors and ensures correct function and ergonomics. Given Data / Assumptions: “Right-hand” and “left-hand” imply mirror symmetry across a plane. Assembly interfaces often depend on handed geometry (mounting holes, flanges). Interchangeability requires identical geometry, which mirror parts do not have. Concept / Approach: Mirror images are congruent only after reflection (an operation not available in physical assembly without re-machining). As-manufactured parts preserve handedness; attempting to substitute the opposite hand usually misaligns features or reverses motion (as in thread direction). Step-by-Step Solution: Identify whether the part's function depends on handedness (e.g., lever direction, thread lead).Compare mating features (bosses, holes) on RH vs LH versions; they do not overlay without reflection.Conclude that RH/LH are not interchangeable by design. Verification / Alternative check: Assembly drawings and BOMs list separate part numbers for RH and LH components, underscoring non-interchangeability. Why Other Options Are Wrong: Claims that shims, bilateral tolerances, or “symmetric features only” restore interchangeability ignore the fundamental mirror reversal of geometry. Common Pitfalls: Ordering the wrong hand; flipping drawings without updating part numbers; assuming symmetry where it does not exist. Final Answer: Incorrect

Question 11

2D Drawing Representation — Definition Check In technical drawing terminology, is a counterbore defined as a cylindrical recess around a hole that is machined to seat a bolt head or nut flush below the surface, typically specified by symbol, diamete…

Accepted Answer

Introduction / Context: A counterbore is a common feature in mechanical drawings and shop practice. The purpose is to allow a bolt head, socket head cap screw, or nut to sit below or flush with a part surface to avoid interference with mating parts, sliding surfaces, or safety covers. This question checks whether the definition that a counterbore is a cylindrical recess around a hole used to receive a bolt head or nut is accurate. It also tests recognition of the way such features are specified on drawings using standards compliant notation and dimensions. Given Data / Assumptions: The base hole is already present or will be drilled through to allow the fastener shank to pass. The recess is cylindrical with a flat bottom and a diameter larger than the shank hole. Dimensioning normally includes counterbore diameter and depth, sometimes symbolized with the counterbore mark. Concept / Approach: A counterbore differs from a countersink. A countersink is a conical recess used for flat head screws, while a counterbore is a cylindrical pocket for hex heads, socket heads, or nuts. The definition in the stem matches the cylindrical, flat bottom geometry and the intended function of seating hardware below the surface. Step-by-Step Solution: 1) Identify geometry: cylindrical recess with flat bottom concentric to the through hole.2) Identify purpose: to clear and seat a bolt head or nut so that the top surface remains unobstructed.3) Check standards usage: drawings specify counterbore symbol, diameter, and depth along with the hole diameter.4) Compare with alternatives: countersink is conical; spotface is shallow planar cleanup around a hole. Verification / Alternative check: Handbooks and drafting standards show callouts such as: hole diameter, counterbore symbol, counterbore diameter, and counterbore depth. Shop practice for socket head cap screws routinely uses counterbores for clearance and safe assembly. Why Other Options Are Wrong: Incorrect conflicts with standard definitions. Partially correct and Context-dependent add qualifiers that are not necessary for the core definition. Not enough information is inapplicable because the geometric description is complete and unambiguous. Common Pitfalls: Confusing counterbore with countersink; forgetting to specify depth; omitting tolerance or finish requirements for the recess bottom when needed. Final Answer: Correct

Question 12

Edges and Intersections — Concept Check When a curved surface meets a plane surface on a part, does their intersection create a real edge line that should be represented in orthographic views when it is visible?

Accepted Answer

Introduction / Context: Understanding when edges appear is fundamental for reading and creating accurate orthographic drawings. A real edge occurs where two surfaces intersect and form a change in surface orientation. This item asks whether the intersection between a curved surface and a plane surface produces an edge that should be shown on views when visible and not hidden by other geometry. Correct edge representation prevents ambiguity during manufacturing and inspection. Given Data / Assumptions: One surface is curved, such as a cylindrical or spherical region. The other surface is planar, such as a machined face. Projection is orthographic using standard third angle or first angle conventions. Concept / Approach: Edges are loci of points where two surfaces intersect. If the intersection is real, it generates a line in the view where it projects as an outline or visible line. When the intersection is tangent, there is no abrupt change of surface normal, so a true edge line is not drawn. The statement in the stem refers to an intersection, not tangency, therefore a visible edge is correct when the line is in view and not obscured. Step-by-Step Solution: 1) Determine whether the two surfaces actually intersect rather than merely touch tangentially.2) If they intersect, identify the curve of intersection and its projection in each principal view.3) Draw the edge as a visible line where not hidden; use hidden lines where appropriate.4) Omit edge lines at purely tangent transitions, replacing them with smooth contours only. Verification / Alternative check: Compare with standard drafting rules: real intersections create edges; tangencies do not. Section views and auxiliary views confirm the presence and shape of the edge when needed. Why Other Options Are Wrong: Incorrect denies true intersections. Partially correct and Only in section views add limits that do not apply. Only if dimensioned confuses representation with annotation. Common Pitfalls: Mistaking tangency for intersection; drawing edges where a fillet actually blends surfaces instead of forming a sharp intersection. Final Answer: Correct

Question 13

Conventional Breaks and Symbols — Economy and Clarity May simplified conventional representations that deviate from exact orthographic geometry be used on drawings to improve clarity and speed, provided the meaning is standardized and unambiguous?

Accepted Answer

Introduction / Context: Engineering drawings use a shared graphic language. Exact geometry for every feature can be time consuming to draw and may even reduce legibility. Conventional representations use agreed symbols, breaks, and simplified outlines to convey complex features quickly without sacrificing meaning. This question checks whether such simplifications are permitted to enhance economy and clarity when they are standardized and properly annotated. Given Data / Assumptions: Standards define thread symbols, break symbols, knurl conventions, and repetitive feature abbreviations. Manufacturing and inspection personnel are trained to read these conventions. Deviations from true exact projections remain faithful to design intent. Concept / Approach: Conventional representation is a codified shortcut. A threaded shaft is drawn with symbolic lines instead of every helical profile. Long uniform parts are broken with a zigzag to save space. Springs are drawn with simplified turns. The key is standardization so that the reader always interprets the symbol consistently, preserving function and tolerance information. Step-by-Step Solution: 1) Identify features that are complex to render exactly (threads, gears, knurls, springs).2) Replace literal geometry with standard symbols and notations that are widely recognized.3) Ensure that critical dimensions and tolerances are still fully specified.4) Verify that no ambiguity results and that manufacturing can meet intent. Verification / Alternative check: Compare time to draw and clarity of reading for a fully detailed spring versus a conventional symbol. The conventional version is faster and often clearer while remaining unambiguous. Why Other Options Are Wrong: Incorrect denies established drafting practice. Only for threads or Only for springs is too narrow. Only for academic drawings ignores widespread industrial use. Common Pitfalls: Inventing personal symbols that are not standard; omitting necessary dimensions under the assumption that a symbol implies them automatically. Final Answer: Correct

Question 14

Edges on Contoured Surfaces — Representation Rule If a plane cuts a contoured surface on a part, should a line representing their real intersection be drawn on the view when it is visible, rather than omitting any edge entirely?

Accepted Answer

Introduction / Context: Readers rely on edge lines to understand where surfaces meet. The statement claims that when a plane intersects a contoured surface, no line is drawn. That is contrary to standard practice. When a true intersection exists, its projection is represented as an edge in visible or hidden form as appropriate. Omitting the line would conceal important geometry and can lead to misinterpretation in manufacturing and inspection. Given Data / Assumptions: The plane truly intersects, rather than merely touching tangentially. Orthographic projection rules for visible and hidden lines apply. No fillet is blending away the abrupt change of surface orientation. Concept / Approach: A line appears in the view wherever there is a discontinuity in surface direction that projects to the viewer. A real intersection between two surfaces creates such a discontinuity. In contrast, tangency produces no visible edge because the surface normal changes smoothly without a sharp break. Therefore, a plane cutting a contoured surface yields an intersection curve that should be drawn to show the real edge when visible. Step-by-Step Solution: 1) Confirm that the relationship is intersection, not tangency.2) Determine the shape of the intersection curve and its projection on each view.3) Draw the line as visible where unobstructed and as hidden where occluded.4) If a fillet blends the surfaces, omit a sharp edge and show only the smooth contour. Verification / Alternative check: Section views and auxiliary views often reveal the intersection directly and justify the corresponding edge representation on principal views. Why Other Options Are Wrong: Correct would endorse omitting a true edge. The other distractors restrict a general rule without justification because edges are drawn regardless of whether they are dimensioned or only in auxiliary views. Common Pitfalls: Drawing edges for tangent contacts; failing to update hidden lines when visibility changes due to viewpoint or additional features. Final Answer: Incorrect

Question 15

Feature Terminology — Boss on a Part In mechanical terminology, is a boss a short raised protrusion that stands proud of a part surface, often used to provide extra thickness for a hole, thread, or bearing seat?

Accepted Answer

Introduction / Context: Many parts include localized thickening to support functional features such as threaded inserts, alignment pins, and bearing seats. This thickening is commonly called a boss. Recognizing the correct term and its purpose is important for clear communication between design, tooling, and manufacturing. The question asks whether a boss is a short raised protrusion above a part surface used to house or reinforce a functional feature. Given Data / Assumptions: The protrusion is integral to the part and provides local material buildup. Typical uses: threaded holes, dowel alignment, mounting pads, bearing lands. Geometry is generally cylindrical or rounded but may be shaped by design needs. Concept / Approach: A boss is distinguished from a lug and a flange. A lug is an ear like projection used mainly for attachment, often with a transverse hole. A flange is a rim or collar that extends to provide mounting or increased stiffness around an opening. A boss is specifically a localized thickening that often centers on a hole axis to provide engagement length or load spread. Step-by-Step Solution: 1) Identify the raised feature and its functional role.2) If the aim is local thickness for threading or bearing, classify it as a boss.3) If the projection serves as an attachment ear, classify as a lug.4) If it is a collar like rim around an opening, classify as a flange. Verification / Alternative check: Common standards and design handbooks show bosses with callouts for hole size, thread designation, and fillet radii at the base to reduce stress concentration. Why Other Options Are Wrong: Incorrect contradicts standard usage. Partially correct understates the definition. Only for plastic parts and Only for decorative use impose false limits, as bosses appear in metals and composites for structural reasons. Common Pitfalls: Confusing boss with flange or lug; omitting fillets at the boss base which can create stress risers; ignoring draft angles in molded parts. Final Answer: Correct

Question 16

Planes and Contours — Contact Possibilities Is the claim that a plane surface cannot intersect or be tangent to a contoured surface accurate, or can a plane both intersect and be tangent depending on geometry and positioning?

Accepted Answer

Introduction / Context: Design and inspection often use planes to evaluate or generate features on complex contoured surfaces. The assertion that a plane surface cannot intersect or be tangent to a contoured surface is contrary to basic geometry. This question checks the understanding that a plane can have several relationships with a curved or contoured surface, including intersection along a curve and tangency at a single line or point depending on the specific shape. Given Data / Assumptions: Contoured surfaces include cylinders, cones, spheres, and freeform profiles. A plane can be oriented arbitrarily in space relative to the part. Standard projection rules apply for representing the resulting line or contact region. Concept / Approach: When a plane intersects a curved surface, the set of all points common to both is a curve, for example an ellipse on a cylinder or a circle on a sphere under special conditions. When a plane is exactly tangent, the surfaces meet without cutting, sharing a common tangent direction at the contact locus, and no sharp edge line is drawn in orthographic views. Therefore the absolute negative claim in the stem is incorrect. Step-by-Step Solution: 1) Visualize relative orientation between the plane and the curved surface.2) For most orientations, the plane cuts the surface producing a true intersection curve.3) For the special tangent orientation, the plane just touches with matched slope and forms no sharp edge.4) Represent intersection with visible or hidden edges; represent tangency with smooth contour only. Verification / Alternative check: Classic examples include slicing a cylinder or sphere with a plane. CAD section tools show the resulting curves and confirm basic geometric relationships. Why Other Options Are Wrong: Correct repeats the false statement. Only tangent but not intersect and Only intersect but not tangent impose artificial limits. Context-dependent is unnecessary because the general geometric possibilities are known. Common Pitfalls: Drawing an edge at a tangent contact; misidentifying section curves due to projection distortion in non principal views. Final Answer: Incorrect

Question 17

Feature Terminology — Lug vs Flange vs Boss Is a lug best described as a flattened collar or rim around a cylindrical part for attachment, or is a lug more correctly an ear like projection used for fastening, distinct from a flange or boss?

Accepted Answer

Introduction / Context: Clear feature vocabulary avoids confusion during design reviews and fabrication. Lug, flange, and boss are related but distinct. The statement claims that a lug is a flattened collar or rim around a cylindrical part used for attachment. That description aligns more closely with a flange. A lug is typically an ear like projection that extends from a body to accept a bolt, pin, or clevis connection. This question distinguishes these commonly mixed terms. Given Data / Assumptions: Lug: projection with a hole or slot for fastening or alignment. Flange: collar or rim around a cylinder or opening for mounting and stiffness. Boss: localized thickening, often cylindrical, to support a hole or bearing. Concept / Approach: Terminology depends on geometry and function. A collar like rim encircling a cylindrical feature is a flange, not a lug. An ear like single sided projection that facilitates attachment is a lug. A local thickened pad used to host a thread is a boss. Classifying correctly leads to accurate callouts, procurement, and tooling decisions. Step-by-Step Solution: 1) Examine geometry: rim around a cylinder indicates flange; protruding ear indicates lug.2) Check function: attachment via a discrete projection with a bolt hole is a lug.3) If the aim is local thickness for threading, it is a boss.4) Apply consistent naming in drawings and bills of materials. Verification / Alternative check: Catalog and standards references show flanges as ring like collars and lugs as bracket like ears. Many castings include lugs for mounting to frames where flanges would be impractical. Why Other Options Are Wrong: Correct would equate lug with flange. Partially correct admits confusion but does not fix the mislabel. Context-dependent is unnecessary because the definitions are widely used. Not enough information does not apply because the geometric cues are explicit. Common Pitfalls: Drawing a flange but calling it a lug; dimensioning a lug without adequate fillet radii or thickness for load path strength. Final Answer: Incorrect

Question 18

Surface Textures — Knurl Function and Representation Is knurling a patterned texture formed on a surface to improve grip or provide additional surface area for press fits, adhesives, or decorative cues, typically shown by a conventional symbol on dr…

Accepted Answer

Introduction / Context: Knurling is a widely used manufacturing operation that rolls a patterned texture into a cylindrical or flat surface. The primary goals are improved hand grip, indexing markers, and increased effective surface area for certain assembly methods. This question checks whether the stated definition captures both function and representation on drawings using standard conventions rather than literal depiction of every ridge. Given Data / Assumptions: Knurled patterns include straight, diamond, and diagonal forms. Drawings usually use a conventional symbol and a note specifying pitch, pattern, and coverage. The feature is produced with a knurling tool on a lathe or knurling rollers in other processes. Concept / Approach: The textured geometry increases friction for hand interface and can improve retention in press fits or bonding. Conventional representation avoids clutter by showing a simplified hatch or symbol while specifying critical parameters in notes, ensuring repeatable manufacturing without redrawing every tooth. Step-by-Step Solution: 1) Identify the need: grip enhancement, tactile feedback, or decorative requirement.2) Specify pattern type, pitch, major diameter before and after knurl, and length of coverage.3) Use the standard symbol or simplified hatch to indicate knurled area.4) Confirm that tolerances and edges adjacent to the knurl are appropriately protected to avoid burrs. Verification / Alternative check: Compare the usability of a smooth knob with a knurled knob in oily environments. The knurled version provides better grip and safety without additional components. Why Other Options Are Wrong: Incorrect contradicts industry practice. Only decorative ignores functional benefits. Only for aluminum is false since knurling is applied to many metals and some plastics. Partially correct understates the role and representation. Common Pitfalls: Failing to specify pitch and pattern; placing knurls on surfaces that must mate with tight tolerance components without accommodating texture height. Final Answer: Correct

Question 19

Fillet vs Round — Interior and Exterior Blends Is a fillet correctly defined as a rounded exterior blend between surfaces, or is a fillet specifically an interior concave blend while the exterior convex blend is called a round?

Accepted Answer

Introduction / Context: Precise naming of blends is critical in design, machining, and inspection. The term fillet is often used loosely, but in drafting and manufacturing terminology it has a specific meaning. The stem claims that a fillet is a rounded exterior blend. That is not correct. Fillet refers to an interior concave blend between intersecting surfaces. The matching exterior convex blend is a round. Correct use of these terms avoids miscommunication when specifying radii and surface transitions. Given Data / Assumptions: Two surfaces meet either internally or externally. Blending replaces a sharp corner with a radius to reduce stress and improve flow or safety. Drawings must call out radius values and tolerances. Concept / Approach: Interior corner: use a fillet. Exterior corner: use a round. This convention is widely taught and supported by drafting standards and CAD tools. The rationale is clarity: different machining or molding operations may create interior versus exterior blends, and inspection points differ accordingly. Step-by-Step Solution: 1) Determine whether the corner is inside (concave) or outside (convex).2) If inside, specify a fillet with its radius value; if outside, specify a round with its radius.3) Ensure that fillets at boss bases and pocket bottoms are sized to reduce stress concentration.4) Verify clearance for mating parts when rounds are applied to external edges. Verification / Alternative check: CAD commands and CAM toolpaths typically label features as fillet for interior edges and round for exterior edges, reflecting shop floor practice. Why Other Options Are Wrong: Correct repeats the incorrect definition. Partially correct or Context-dependent suggests ambiguity where the standard usage is precise. Not enough information does not apply because interior versus exterior is clearly stated. Common Pitfalls: Using fillet generically for all radiused corners; forgetting that large rounds may interfere with assemblies or reduce sealing land width. Final Answer: Incorrect

2D Drawing Representation Questions