Question

A metal disc of $20$ mm diameter is to be punched from a sheet of $2$ mm thickness. The punch and the dia clearance is $3$%. The required punch diameter is

• A. $19.88$ mm
• B. $19.94$ mm
• C. $20.06$ mm
• D. $20.12$ mm

Answer 1

The correct option is A $19.88$ mm

Given, punched diameter,
$d=20$ mm
Sheet thickness,
$t=2$ mm
Clearance: $c=3$% of t
Punch diameter
$D=d-2c$
$=20-2\times \frac{3}{100}\times 2$
$=19.88\text{mm}$