Maharashtra HSC Mechanical Maintenance (Bifocal) case studies
Maharashtra HSC Mechanical Maintenance (Bifocal) · Put your knowledge to work in context.
The Maharashtra HSC Mechanical Maintenance (Bifocal) is a vocational higher secondary credential awarded by MSBSHSE. It pairs general HSC subjects with a bifocal trade component that prepares students for technician-level work in manufacturing plants, workshops, and maintenance departments, and for further study in polytechnic or engineering programmes. The Maharashtra HSC Mechanical Maintenance (Bifocal) case studies are 5 cases and about 4,188 words.
1Oversize Dowel Pins: Instrument Error or Real Rejects?
A trainee inspector in a press-tool shop is checking 50 hardened EN8 dowel pins, drawing size Ø12 h6 (0 / −0.011 mm), with a 0–25 mm outside micrometer. The micrometer was zeroed against its setting standard in the air-conditioned stores at 20 °C, then carried to the shop floor beside a heat-treatment furnace where the ambient is 34 °C.
824 words, about 4 min2Soft Shafts After Hardening and Tempering
A heat-treatment bay must supply 40 splined shafts, Ø30 × 220 mm, made from EN19 (AISI 4140) bar with a mill certificate showing 0.40 % C, 1.05 % Cr and 0.20 % Mo. The drawing calls for 40–45 HRC after hardening and tempering, with 0.30 mm radial grinding allowance left on all diameters.
763 words, about 4 min3Taper, Chatter and Rising Rejects on a Centre Lathe
An operator is turning 200 plain-carbon shaft blanks (0.35 % C) from Ø45 mm to Ø40 mm over a 300 mm length between centres on a centre lathe, using a coated carbide insert, 600 rpm, 0.2 mm/rev feed and 2.5 mm depth of cut per pass. The insert was indexed 18 pieces ago; supplier data suggests about 40 pieces per edge at these conditions.
815 words, about 4 min4Confined-Space Entry Into a Fuel-Oil Day Tank
A three-man crew is to clean sludge from a 6 m³ rectangular steel fuel-oil day tank, 2.2 m deep, entered through a 500 × 400 mm manhole. The tank was drained two days ago and flushed with diesel.
889 words, about 4 min5Repeated 6316 Bearing Failures on an Elevator Motor
A 75 kW, 4-pole TEFC motor (1475 rpm) drives a bucket elevator through a V-belt. Its drive-end bearing is a single-row deep-groove ball bearing 6316 (80 × 170 × 39 mm), grease-lubricated in a cast-iron housing with a relief plug.
897 words, about 4 min