Maharashtra SSC Engineering Drawing ITI flashcards
Maharashtra SSC Engineering Drawing ITI · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- First-angle projection arrangement
- In first-angle projection the object lies between observer and plane, so the top view is drawn below the front view and the left side view is drawn on the right.
- Isometric scale factor
- True isometric projection foreshortens all three axes equally by about 0.816. Isometric drawing uses full scale along the axes, so the isometric scale is roughly 0.82 of true length.
- Tolerance formula
- Tolerance is the difference between the upper and lower limits of a dimension, equal to the maximum limit minus the minimum limit, and is always a positive quantity.
- Hole basis system
- A system of limits and fits in which the hole has zero fundamental deviation (designation H) and the shaft letter fixes the type of fit.
- Development of a cone
- The unfolded lateral surface of a right cone is a sector whose radius equals the slant height and whose angle equals 360 degrees times base radius divided by slant height.
- Ribs not hatched
- When a cutting plane passes lengthwise through a rib, web or bolt, the feature is shown in outline but not hatched, so the section does not appear misleadingly thick.
- Cutting plane line
- A chain thick line with arrows at the ends showing the direction of sight, labelled with capital letters that match the title of the sectional view.
- Sunk key
- A key seated partly in a keyway cut in the shaft and partly in the hub, used to transmit torque and prevent relative rotation between them.
- Flange coupling
- A rigid coupling in which two flanged hubs, keyed to the shaft ends, are bolted together; it transmits torque and requires accurate shaft alignment.
- Freehand sketching technique
- Draw light construction lines to fix proportions, then darken final outlines; judge lengths against a chosen unit and keep pencil strokes short and relaxed.
- Drawing scale ratio
- Scale is the ratio of drawing length to actual length. A scale of 1:2 means the drawing is half size; 2:1 means it is twice full size.
- Concentric-circle ellipse method
- Draw circles equal to the major and minor axes, divide both into the same number of equal sectors, and project intersections to obtain points on the ellipse.
- Tangent from external point
- Bisect the line joining the external point to the circle centre, then draw a semicircle on that line; its intersections with the circle give the tangent points.
- Dividing a line equally
- Draw an auxiliary line at any angle, step off the required number of equal divisions, join the last division to the line end, and draw parallel lines through the divisions.
- Regular hexagon construction
- For a hexagon, the circumradius equals the side length, so stepping the side around a circle of that radius gives the six vertices.
- Hidden line style
- Hidden edges use short dashes about 2 to 3 mm long separated by gaps of about 1 mm, drawn thinner than visible outlines.
- Dimension line rules
- Dimension lines are thin continuous lines with arrowheads at both ends, placed outside the outline where possible, with the numeral above the line.
- Lettering height ratio
- IS 9609 single-stroke lettering uses a height-to-stroke-width ratio of 14:1 for style A and 10:1 for style B, with standard heights from 2.5 to 20 mm.
- Point projection distances
- The front view's distance from the XY line equals the point's height above HP; the top view's distance equals its distance in front of VP.
- Line perpendicular to HP
- A line perpendicular to the horizontal plane appears as a point in the top view and shows its true length in the front view.
- True length of inclined line
- A line inclined to both planes shows no true length in either view; true length is found by rotating the line parallel to a plane or by the auxiliary-plane method.
- Solid resting on HP
- A solid resting on its base on HP shows the true shape of the base in the top view and a rectangle or triangle in the front view.
- Cone slant height formula
- For a right cone, the slant height equals the square root of the sum of the squares of the base radius and the axis height.
- Auxiliary-plane method
- A new reference line is drawn parallel to the edge view of an inclined face, and the view projected on that plane shows the true shape of the face.
- Cylinder development
- The lateral surface of a right cylinder unfolds into a rectangle whose width equals the circumference, 2 times pi times radius, and whose height equals the cylinder height.
- Triangulation development
- A method for developing oblique solids and transition pieces by dividing the surface into triangles, finding true lengths of all sides, and laying them out in sequence.
- Non-isometric lines
- Lines in an isometric drawing that are not parallel to the three isometric axes; their true lengths and angles cannot be measured directly and must be located by coordinates.
- Cabinet oblique projection
- An oblique projection in which the receding axis is drawn at half scale, usually at 45 degrees, while the front face is shown in true shape.
- Clearance fit
- A fit in which the shaft is always smaller than the hole, so the minimum clearance is positive and the parts can move relative to each other.
- Woodruff key
- A semicircular disc key seated in a matching milled keyway in the shaft; it transmits torque and is often used in machine tools and automotive assemblies.
- Tap bolt versus through bolt
- A tap bolt passes through a clearance hole in one part and threads into the other; a through bolt passes through both parts and is secured with a nut.
- Drawing title block
- A block, usually at the bottom right of the sheet, giving part name, drawing number, scale, material, projection symbol and the signatures of those who drew and checked it.