Profile of Metric Thread (External Thread)
This post explains shows the simple steps to draw the standard profile of metric external thread.
Metric thread system is created by Bureau of Indian Standards by adopting of ISO (an international organisation of standardisation).
In metric thread system, the shape of the external and internal thread varies.
Thus, this thread system also called as unified thread system.
The ISO metric system is designated as letter M followed by major diameter in mm multiplied by a pitch in mm.
For instance, in M50 * 6, the major diameter of the thread is 50 mm and pitch of the thread is 6 mm.
Let us draw, the standard profile of metric external thread to the scale 1:1 whose pitch is 40 mm. Provide other dimensions as per standards.
First, draw a number of vertical lines for a distance of P/2. i.e. 20 mm.
The distance of major diameter D is calculated by 0.866 × P.
That is D = 0.866*40 = 34.64 mm.
Draw the two horizontal thick line separated by distance D.
Draw a thin line at an offset distance of D/8 from a top thick line.
That is D/8 = 34.64/8 =4.33 mm
Draw another thin line at offset distance D/6 from the bottom line.
That is D/6 = 34.64/6 = 5.77 mm.
With respect to thick lines, draw a triangle by joining the intersection point as displayed on the screen.
The angle made between the flanks should be 60°.
With respect to a triangle, draw an arc at the root with any suitable method.
The crest is made flat.
Hatch the portion as displayed on the screen.
Complete the profile with the required dimensions.
Video Link:
This post explains shows the simple steps to draw the standard profile of metric external thread.
Metric thread system is created by Bureau of Indian Standards by adopting of ISO (an international organisation of standardisation).
In metric thread system, the shape of the external and internal thread varies.
Thus, this thread system also called as unified thread system.
The ISO metric system is designated as letter M followed by major diameter in mm multiplied by a pitch in mm.
For instance, in M50 * 6, the major diameter of the thread is 50 mm and pitch of the thread is 6 mm.
Let us draw, the standard profile of metric external thread to the scale 1:1 whose pitch is 40 mm. Provide other dimensions as per standards.
First, draw a number of vertical lines for a distance of P/2. i.e. 20 mm.
The distance of major diameter D is calculated by 0.866 × P.
That is D = 0.866*40 = 34.64 mm.
Draw the two horizontal thick line separated by distance D.
Draw a thin line at an offset distance of D/8 from a top thick line.
That is D/8 = 34.64/8 =4.33 mm
Draw another thin line at offset distance D/6 from the bottom line.
That is D/6 = 34.64/6 = 5.77 mm.
With respect to thick lines, draw a triangle by joining the intersection point as displayed on the screen.
The angle made between the flanks should be 60°.
With respect to a triangle, draw an arc at the root with any suitable method.
The crest is made flat.
Hatch the portion as displayed on the screen.
Complete the profile with the required dimensions.
Video Link:
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