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.
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 a minor diameter?
Minor Diameter: The smallest diameter of the thread of the screw or nut. The term “minor diameter” replaces the term “core diameter” as applied to the thread of a screw and also the term “inside diameter” as applied to the thread of a nut.
What is the major and minor diameter of threads?
The major diameter of a thread is the diameter of the imaginary co-axial cylinder that just touches the crest of an external thread or the root of an internal thread. 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.
How do you find the minor diameter of a metric thread?
Metric thread root form is defined in ISO 965-1 standard….Metric Thread Formulas:
| Parameter | Equation |
|---|---|
| Thread basic pitch diameter [d2 , D2] | d2=D2=d−2×38H=D−2×38H |
| Thread basic minor diameter [d1 , D1 ] | d1=D1=d−2×58H=D−2×58H |
Which method is suitable for measuring minor diameter of internal thread?
floating carriage diameter measuring machine
The minor diameter is measured by a comparative method by using floating carriage diameter measuring machine and small V pieces which make contact with the root of the thread. These V pieces are made in several sizes, having suitable radii at the edges. V pieces are made of hardened steel.
How do you find the minor diameter of a tap?
Calculate the minimum diameter of the tap drill (cut-off diameter for re-grinds) as ddr-min = d1-min – srmin. The minimum run-out can be zero in the most conservative case. For M6 × 1 thread ddr-min = 4.997 – 0.000 = 4.997 mm.
How do you calculate tap drill size?
As a rule of thumb, for Metric threads, the tapping drill can be calculated by subtracting the pitch from the diameter of the thread. eg for an M5x0. 75 thread the tapping drill is 5-0.75mm = 4.25mm. For Imperial (inch) threads the tapping drill size is calculated in the same way, diameter minus pitch.