Types of Hacksaw Blade & Hacksaw Frame
What is Hacksaw?
Types of Hacksaw Blade & Hacksaw Frame :- A hacksaw is a fine-toothed saw, originally designed to cut metal whereas a bow saw is the equivalent saw for cutting wood. Hacksaws are hand tools used to cut metal that is too thick or hard for the cutters.
A Hacksaw consists of basically two main elements:
1) A frame with a handle
2) A blade.
Hacksaw blades are usually classified as either flexible or hardened; the variations in terms of coarseness, teeth pitch and length also have to be taken into consideration when you are choosing the proper hacksaw for your task.
Hacksaw Design
Most of the hacksaws are a type of handsaws with a C-shaped walking frame to hold the blade under tension. Such type of hacksaws usually has a handle, mostly a pistol grip, having pins for joining a narrow disposable blade. To accommodate blades of different sizes the frames may also be adjustable. A screw or some other mechanism can be used to put the thin blade under tension.
In most of the frame saws the hacksaws, the blade could be installed on the teeth having its face towards or away from the holder which is used in cutting operation whether on the push or the pull stroke. Normally for cutting vertically downwards the hacksaw blades are set to be facing forwards with work held in a bench vice.
Parts of Hacksaw
Following are given the main part of a hacksaw:-
1) Hacksaw frame
2) Hacksaw blade
3) Adjustable wing nut
4) Adjustable screw
5) handle
6) stud
1. Hacksaw Frame
Its shape is like the English letter “C” of the English language. On one of the ends of these arms, there is a handle is fixed and on the other end, there is a pin is fixed. A hacksaw blade is first fitted on these pins and then it is tightened according to need with the help of a flying nut or the wing nut. Mainly there are two types of hacksaw frames which are as follows:
Types of Hacksaw Frame
Following are given the two main types of hacksaw frames: the first one is the Fixed Hacksaw Frame and the other one is the adjustable Hacksaw frame
1) Fixed Hacksaw Frame
To make this type of hacksaw frame, a portion of the flat iron strip is bent at the right angle. In this kind of frame, the hacksaw blades having a specific size can be fixed neither of the short size or long size. There are two types of handles that are used here:
1- Straight handle
2- Pistol type handle
2) Adjustable Hacksaw Frame
In an adjustable type of hacksaw frames, the structure is a little different from a fixed frame. The frame of the adjustable hacksaw is made in two parts. These components can be adjusted at various lengths. Due to this in this hacksaw, big and small hacksaw blades of the different types can be used.
There are sufficient numbers of pin and channels to pull, adjust and set them. These types of handles are used in this hacksaw:
1- Straight handle
2- pistol-type handle
3- Tubular type handle
4- Flexible Blades
2. Hacksaw Blade
The standard hacksaw blade lengths are 10 to 12 inches (250 to 300 mm). Blades can vary in size and be as small as 6 inches (150 mm). Powered hacksaws generally use large blades in a variety of sizes, or small machines use the same hand blades for small operations.
The pitch of the teeth can be from 14 to 32 TPI (teeth per inch) for a hand blade, with nearly 3 TPI for a large power hacksaw blade. The thickness of the material which is to be cut decides which blade is to be used, with a minimum of three teeth in the material. As hacksaw teeth are so small in size, they are placed in a “wave” set. As for the other saws they are placed from side to side to provide clearance or kerf when sawing, but the set of a hacksaw changes generally from tooth to tooth in a curve, rather than alternate teeth set left and right.
‘Low Alloy’ Blades
Types of Hacksaw Blade: – Hacksaw blades are normally very brittle, so care needs to be taken by the operator to avoid brittle fracture of the blade. Early blades which were made of carbon steel are now termed as ‘low alloy’ blades and are relatively flexible and soft. They prevent breakages, but also wore out rapidly. Except where cost is a major concern, this type is now rarely used and considered as out of date. ‘Low alloy’ blades are the only type available for the junior hacksaw, which results in the limited usefulness of this otherwise popular saw.
For several decades now, high-speed steel has been used for the teeth of hacksaw blades, providing greatly improved cutting and tooth life. In beginning, these blades were first accessible in the ‘All-hard’ mode which cut perfectly but it was very weak. This resulted in their limited practical use to bench work on a work piece that was firmly held in a vice. A softer form of the high-speed steel blade was also available, which wore better and resisted breakage to an extent, but was less stiff and so less preferred for accurate sawing.
