Maharashtra HSC Workshop Science & Calculation case studies
Maharashtra HSC Workshop Science & Calculation · Put your knowledge to work in context.
Workshop Science & Calculation is a Vocational stream subject in the Maharashtra State Board HSC curriculum, taken by students who pair shop-floor trade practice with the theory that supports it. It suits candidates who intend to move into machining, fitting, fabrication, maintenance or a small manufacturing enterprise, and who need to read a drawing, choose a material, set a machine and cost a job with confidence. The Maharashtra HSC Workshop Science & Calculation case studies are 5 cases and about 3,765 words.
1Rough and finish turning of a C45 shaft on a geared-head lathe
A 320 mm long bar of C45 (black, Ø62 mm) must be turned to Ø56 h6 over its whole length on a geared-head centre lathe. The headstock gives 63, 90, 125, 150, 200, 250, 315 and 400 rpm; the feed gearbox gives 0.10, 0.15, 0.20 and 0.25 mm/rev.
799 words, about 4 min2Set-over taper and M20 × 2.5 thread on a centre lathe
An adapter is turned from Ø60 mm MS bar on a centre lathe: a 1:10 taper on diameter over a 120 mm length (Ø60 down to Ø48), followed by an M20 × 2.5 external thread on the small end. The lathe has a 6 mm-pitch lead screw, a change-gear set of 30, 40, 50, 60, 80, 100 and 120 teeth, a compound rest graduated in degrees and minutes with 90 mm of slide travel, and a tailstock set-over of up to 20 mm on a 300 mm bed length.
772 words, about 4 min3Dowels specified in inches, measured with the wrong micrometer
A batch of 60 dowel pins is turned from EN8 bar to a drawing size of Ø 0.5000 in, tolerance +0.0005 in / −0.0000 in, surface finish Ra 0.4 µm. The shop floor is at 34 °C; the inspection room and the micrometer were calibrated at 20 °C.
706 words, about 4 min4Loading, energy and power factor on a small workshop distribution board
A fabrication shop is fed from a 415 V, 3-phase, 50 Hz supply through one distribution board. The loads are: a lathe motor rated 7.5 kW output, η 88%, pf 0.82; an air compressor rated 2.2 kW output, η 80%, pf 0.78, running about 40% of the shift; and 1.2 kW of single-phase lighting and fans spread evenly over the three phases (240 V phase-neutral).
747 words, about 4 min5Quoting 120 MS flanges from bar stock
An order for 120 MS flanges is to be quoted from Ø80 mm bright MS bar at ₹68/kg (ρ = 7850 kg/m³). Each flange finishes 22 mm long; a 2 mm facing allowance is left on each end, and the hacksaw removes a 3 mm kerf per cut.
741 words, about 4 min