Question

If the distance between two consecutive threads of screw in $1mm$, the pitch of the screw is
A) $0.5cm$
B) $1mm$
C) $0.1mm$
D) $0.5mm$

Answer 1

Hint: Pitch of a screw refers to the distance from the crest of a screw thread to the crest of an adjacent screw thread. A screw thread refers to a ridge wrapped around a cylinder or a cone in the form of a helix.

Complete answer:
Most of us would have wondered how a screw works. When we apply a rotational force on the flat end of a screw, the screw tends to move inwards or outwards a surface, depending upon the direction of rotation. A screw does this with the help of threads or screw threads present in it. A screw thread is a helical structure, which is used to convert between rotational and linear movement or force. It is nothing but the stripe-like structure we see below the flat end and along the axis of a screw.

There are many measurable quantities in a screw like thread angle, pitch, lead and starts. Out of these, lead and pitch are closely related. Lead refers to the distance covered by the screw in one complete rotation i.e. It is the distance covered by the screw when the screw is rotated by $360{}^\circ $.
Pitch of a screw refers to the distance from the crest of a screw thread to the crest of an adjacent screw thread. It can also be defined as the distance between the crests of two consecutive screw threads. Mathematically, pitch of a screw is defined as the ratio of the distance covered by the screw to the number of rotations given. If a single rotation is given, pitch of the screw is equal to the distance covered by the screw. Hence, both lead and pitch of a screw are closely related.

Pitch = distance covered/number of rotations.
If number of rotations = 1, pitch = distance covered = lead
The distance between two consecutive threads is nothing but the distance between the crests of two consecutive screw threads. From the question, we are provided that the distance between two consecutive threads is equal to $1mm$. This is nothing but the distance between the crests of two consecutive screw threads or the pitch of the screw.

So, the correct answer is “Option B”.

Note:
Since lead and pitch of a screw are closely related, there is always a confusion among the two. In most of the screws available in the market, lead and pitch of the screws are the same. Students need not get confused with the terms provided in the question. All they need to understand is that pitch, lead, distance between screw threads and distance between crests of two consecutive threads of a screw, are the same.