Lesson No. 07 Week No. 04 Lesson Name Hacksaw Frame & Blade

 Use:- To cut the material like rod, pipes, plates, sheets of various thickness  Types:- 1. Solid Hacksaw frame:- Only a particular standard length of blade can be fitted to this frame. HACKSAW FRAME

2. Adjustable Hacksaw frame (Flat):- Different standard lengths of blades can be fitted to this frame.

3. Adjustable Hacksaw frame (Tubular):- This is the commonly used type. It gives a better grip and control, while sawing.

 Material:- Low alloy steel or High speed steel HACKSAW BLADES

 Types:- 1.All hard blades :- These blades are hardened to the full length between the pin holes. 2.Flexible blades :- For these types of blades, only the teeth are hardened. Because of their flexibility, these blades are useful for cutting along curved lines.  Pitch:- 1. Coarse – 1.8 mm 2. Medium – 1.4 to 1 mm. 3. Fine – 0.8 mm

 Pitch:- 1.Coarse (1.8 mm) :- For soft synthetic and plastic materials. 2.Medium(1.4 to 1 mm) :- For tool steel, medium hard steel, copper alloys. 3.Fine(0.8 mm) :- For thin work piece sections.

 Blade settings:- 1. Staggered set:- Alternate teeth or groups of teeth are staggered. This arrangement helps for free cutting, and provides for good chip clearance.

2. Wave set:- In this, the teeth of the blade are arranged in a wave form. This type of setting is done blades of fine grade and super fine grade.

QUESTIONS 1. Which type of Hacksaw frame are used in workshop ? 2. Which material are used in Hacksaw blade ? blade ?

CONCLUSION Student will understand Types, Material & uses of Hacksaw & Blade.