# Frequent question: How do you find the minor diameter of a screw?

Contents

The minor diameter can be determined by direct measurement on an optical comparator or by measuring the depth of the thread with a depth micrometer and subtracting twice the measured depth of thread from the major diameter.

## What is the minor diameter of a screw?

The minor diameter is the diameter of an imaginary cylinder that just touches the roots of an external thread and (or) the crests of an internal thread. The crest of a thread is the prominent part of a thread, whether internal or external.

## How do you find the minor diameter of an internal thread?

Minor Diameter ‐ The lower extreme diameter of the thread. The height of the thread = (Major ‐ Minor) / 2. The minor diameter of an internal thread is it’s inside diameter. The minor diameter of an external thread can be measured with GO and NOGO gages or directly with an optical comparator.

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## What is major and minor diameter of threads?

Major Diameter: The largest diameter of the thread of the screw or nut. The term “major diameter” replaces the term “outside diameter” as applied to the thread of a screw and also the term “full diameter” as applied to the thread of a nut. Minor Diameter: The smallest diameter of the thread of the screw or nut.

## How do you measure screw diameter?

To measure the diameter of screws and bolts, you measure the distance from the outer thread on one side to the outer thread on the other side. This is called the major diameter and will usually be the proper size of the bolt.

## How do you find minor diameter?

Identifying Minor Diameter

The minor diameter can be determined by direct measurement on an optical comparator or by measuring the depth of the thread with a depth micrometer and subtracting twice the measured depth of thread from the major diameter.

## What is meant by minor diameter?

: the smallest diameter of a screw thread.

## How do you find the major and minor dia of a thread?

According to page 1528 of The Machinery’s Handbook (29th Ed.), that formula is given as A_S=(π/4)*((d_m+d_p)/2)^2 where the pitch diameter is d_p=d−0.649519×P, and the minor diameter is d_m=d−1.299038×P. I was trying to understand where the definitions of d_p and d_m come from.

## What is major DIA and minor dia?

Major Diameter is the largest diameter of a screw thread. Whereas, Minor Diameter is the smallest diameter of a screw thread.

## What is minor diameter of thread?

The minor diameter is the lower extreme diameter of the thread. Major diameter minus minor diameter, divided by two, equals the height of the thread. The minor diameter of a nut is its inside diameter.

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## What is the minor diameter of a 10 32 thread?

10-32 screws have a diameter of 3/16″ (4.8mm) where as 12-24 screws have a diameter of 7/32″ (5.6mm).

## What is Major Minor and pitch diameter of screw?

a) MAJOR DIAMETER: The largest diameter of a screw thread; measured from the crests on external threads and the roots on internal threads. b) PITCH DIAMETER: The imaginary diameter equal distance between the major and minor diameters.

## What diameter is a #6 screw?

American Screw Sizes

Size Nearest Fraction Millimeter
#6 9/64 3.3
#8 5/32 4.2
#10 3/16 4.8

## What diameter is 12g screw?

For gauge to MM conversion

Self Tapping Screw Gauge (g) Size (mm)
6 3.5
8 4.2
10 4.8
12 5.5

## How do you identify a screw?

Measuring Bolts and Screws

Most commonly, screws and bolts are identified by diameter (of the threaded portion), thread pitch, and length. Length is measured from the point at which the head sits flat with the surface, to the tip of the threads.