Railways NTPC (Technical Ability) Tool Engineering Question Bank Tool Engineering

  • question_answer
    A strip is to rolled from a thickness of 30 mm to 15 mm using a two-high mill having rolls of diameter 300 mm. The coefficient of friction for unaided bite should nearly be:

    A) 0.95                             

    B) 0.5

    C) 0.25                             

    D) 0.07

    Correct Answer: A

    Solution :

    Bite angle, \[\alpha ={{\tan }^{-\,1}}\mu \] \[\cos \alpha =\frac{150-7.5}{150}\] \[=\frac{142.5}{150}=0.95\]


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