Question
Download Solution PDFThe hole opening which is required for screwing conical or tapered necked screws is ______
This question was previously asked in
VSSC ISRO Technician B Fitter Official Paper held on 22 Dec 2012
Answer (Detailed Solution Below)
Option 2 : Counter Sinking
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ISRO Technician B: Fitter Full Test 1
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Download Solution PDFConcept:
Counter boring: Already existing holes in the components can be further machined by counter boring as shown in the figure. In counter boring operations, the hole is already enlarged with a flat bottom to provide proper seating for the bolt head or a nut, which is flushed from the outer surface.
Counter sinking: It is also similar to counter boring, except that the additional machining done on a hole is conical to accommodate the counter sunk machine screw head. Again the depth of counter sinking should be large enough to accommodate the screw head to fully flush with the surface.
A drilling jig is used for drilling holes in a large number of components on an interchangeable basis. In practice, a large variety of drilling jigs are used.
- Template Jig
- Plate Jig
- Vice-type Jig
- Diameter Jig
Jig boring: It is a single-point cutting operation used to produce a precise internal cylindrical surface by enlarging an existing opening in a workpiece. The tool is rotated and advanced parallel to the axis of the hole in the workpiece. Jif boring machines are designed to establish the location of holes in surfaces to the highest level of accuracy possible with a machine tool.
Latest ISRO Technician B Fitter Updates
Last updated on May 28, 2025
-> ISRO Technician Fitter recruitment notification 2025 has been released
->Candidates can fill ISRO Fitter application form from June 2 to 16.
->A total of 20 vacancies are announced for ISRO recruitment 2025 for Fitter.
->Candidates must have passed SSLC/ SSC/ Matriculation and should have NTC/ITI/NAC in ->Fitter Trade Certificate from an NCVT recognized by the government to satisfy the ISRO Technician B Fitter Eligibility Criteria.
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