Machine Design
If d is the normal diameter of a bolt in mm, then the initial tension in kg in a bolt used for making a fluid tight joint as for steam engine cover joint is calculated by the relation

168 d
124 d
151 d
138 d

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Machine Design
Jam nut is a locking device in which

One smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming
Through slots are made at top and a cotter pin is passed through these and a hole in the bolt, and cotter spitted and bent in reverse direction at other end
A slot is cut partly in middle of nut and then slot reduced by tightening a screw
A hard fibre or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip

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Machine Design
A woodruff key is

Fitted in pairs at right angles
All of these
Capable of tilting in a recess milled out in the shaft
A tapered key with head at one end

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