30th April 2020, Period 7, Class 12, Engineering Graphics, Machine Parts - Square Headed Bolt - 1

Dear Students,

Good Morning and a warm welcome to today's class.

It feels really nice to meet up for yet another class this morning.

Recall that in our last class, we had learnt about Hexagonal Headed bolt and its projections. 

Let us now proceed further and learn about Square Headed Bolt and its orthographic views.


Square Headed Bolt

It is another commonly used bolt. The head of the bolt is in the shape of a square prism (or slab). The outer part of the head of the bolt is chamfered at 30 degrees just like the nut. Refer to Fig 1 below. The square bolt comprises of the following lengths just like a hexagonal headed bolt.




Fig 1: A square headed bolt

a. Shank length = The Shank length is the total length of the cylindrical part of the bolt excluding the thickness of the height of the head. It is the sum of the threaded length and the unthreaded length.

b. Threaded length = It is the length of the bolt on which threads are available.

c. The thickness of the head = 0.8 d

Orthographic Views of a Square Headed Bolt

1. For the purpose of constructing the orthographic views of the bolt, we place the bolt on the HP so that its axis is parallel to both the HP and the VP.

2. We start with the LH or the RH Side View (as the question requires). First we construct the square with '1.5 d' diameter. Then the Chamfer circle, the crest circle and the root circle

3. Take the projections to construct the FV of the bolt.

Exercise - Square Headed Bolt - 1 

Position 1

Q 1. Draw to scale 1:1, the Front View and LH Side View of a Square Headed Bolt of nominal diameter 30 mm, placed with its axis parallel to both the HP and the VP.