GATE 2024 Mechanical Engineering: Important basic concepts in Machine Design for GATE 2019 Part-3

The present article (Part-3) contains the important basic concepts in Machine design and related machine drafting technology in Mechanical Engineering. Note down each concept which might help in GATE 2019 Mechanical.

Spiral gears are suitable for transmitting small powers
As pump speed increases its NPSH (Net Positive Suction Head) requirement increases
If pump NPSH requirements are not satisfied, it will be cavitated
Bush roller chain is used in a motorcycle.
The working load for a chain for crane application is expressed in terms of the diameter of the link in cm and given by 500 multiplied by the square of the diameter.
If a square key and shaft are to be of the same material and or of equal strength, the length of the key would be 1.23d, d=diameter of shaft
In a standard coarse thread bolt, the stress concentration is maximum at the root.
Fatigue strength of a surface may be increased by polishing the surface
The maximum deflection allowed in gantry girders is L/1000
The maximum size of the fillet weld that can be used at 3 mm
The maximum size of fillet weld that can be made in a single pass in 6 mm
A rolled steel flat designated as 50 ISF 8 means the flat is 50 mm wide and 8 mm thick.
The column splice is used for increasing length of the column
The minimum thickness steel member exposed to weather and accessible for painting is 10 mm
For determination of allowable stress in axial compression, IS: 800-1962 has adopted secant formula
For accurately, cut gears operating at velocities up to 20 m/sec, the velocity factor v, is given by 6/6+v
Zero axial thrust is experienced in herringbone gears
In order to realize the advantage of fluid friction, it is essential to have parallel oil film in bearing
A Shaft rotating in the anti-clockwise direction at slow speed inside a bearing will be towards the left side of bearing and making metal to metal contact
Bearing characteristics number relating Z-absolute viscosity of lubricant, N-speed of a journal and p-bearing pressure on a projected bearing area is ZN/p