In this article, you’ll learn what is a hacksaw and How it is used in the workshop. with its Parts, Methods, Precautions and Types of hacksaw frame with PDF.
Hacksaw and Its Types
In order to cut metal, rods, pipes, plates or sheets of varied thickness a hacksaw is used. It can be operated by hand or with a hacksaw and the cut edges are cleaner than those cut with a chisel.
Parts of a Hacksaw:
Following are the main two parts of a hacksaw:
- Hacksaw frame
- Hacksaw blade
- Adjustable screw
- Adjustable wingnut
1. Hacksaw Frame
In shape, it looks like the English letter “C”. On one end of these arms, a handle is fixed and on the other end, a pin is fixed. A pin each is the fixed handle and sliding screw itself in which hacksaw blade is fitted. A hacksaw blade is fitted on these pins and then it is tightened according to need with fly nut or wing nut. Mainly hacksaw frames are of two types.
Types of Hacksaw Frame
Following are the main two types of hacksaw frame:
- Fixed Hacksaw Frame
- Adjustable Hacksaw
1. Fixed Hacksaw Frame
For making this type of hacksaw frame, one-piece flat iron strip or pipe is bent at a right angle. In these types of hacksaw frame, only hacksaw blades of a specific size can be fixed, not of the short size or long size. Two types of handles are used:
- Straight handle
- Pistol type handle
2. Adjustable Hacksaw
In these types of hacksaw frame, Its structure is a bit different from a fixed frame. The frame is made in two parts. These parts can be adjusted at different distances. Therefore in this adjustable hacksaw, big and small hacksaw blades of the different standard can be used.
There is adequate provision of pin and grooves to pull, adjust and set them. These types of handles are used. in this hacksaw:
- Straight handle
- Pistol type handle
- Tubular type handle
- Flexible Blade
These frames are generally made of flat strip or thin pipes and their handle are made of wood or aluminium.
2. Hacksaw Blade
On the basis of metal of the job, different types of hacksaw blades are used in a hacksaw. These are made of tungsten steel, high-speed steel and they are hardened and tempered. Their classification depends on three points:
- Size of the blade.
- The number of dents cut on the blade per inch.
- Nature of the blade.
Length of hacksaw blade is generally 8″, 10″ or 12″. Dents of four different grades are cut on them.
Types of Hacksaw Blades
Following are the main types of hacksaw blades:
- Course Grade Hacksaw Blade
- Medium Grade Hacksaw Blade
- Fine Grade Hacksaw Blade
- Superfine Grade Hacksaw Blade
- Ail Hard Blade
1. Course Grade Hacksaw Blade
Hacksaw blade of this grade is used for cutting thickness of mild steel, copper, aluminium and brass etc. It contains 14 to 18 teeth per inch.
2 .Medium Grade Hacksaw Blade
Hacksaw blade of this type is used for cutting all kinds of metals such as cast iron, tool steel, aluminium, brass, high carbon steel etc. From 20 to 24 teeth per inch are cut in this hacksaw blade.
3. Fine Grade Hacksaw Blade
This type of hacksaw blade is mainly used to cut thin pipes ,sheets, tubes etc. It has 24 to 30 dents per inch.
4. Superfine Grade Hacksaw Blade
For cutting extraordinary solid metals and thin metal sheets, thin type of hacksaw blade is used. There are 30 to 32 dents per inch in this type of hacksaw blade.
In all the hacksaw blades of various grades mentioned above, teeth are cut on one or both the edges. These blades are hardened in two different processes and on these depend their nature.
5. Ail Hard Blade
Blades of this nature are hardened and tempered only except the ends having holes. These are used for cutting articles cast iron or mould iron etc.
6. Flexible Blade
In blades of this nature only the cutting teeth and nearby part it hardened and tempered. But this process they become elastic and there is less risk of their being broken in the event of a shock. These blades are used for cutting thin sheets, pipes, curves etc.
Setting of Teeth
Teeth of hacksaw blade are also bent to left or right side as in the case of ordinary saw used for cutting wood. Bending of teeth is known as the setting of teeth. With this setting of teeth the hacksaw blade cuts a slot in the metal of slightly more thickness than that of the blade.
Therefore, because of this slot, the blade does not get stuck while operating it. If the setting is not done, there is a great risk that the blade would get stuck in the metal and get broken. The setting of teeth in a blade is done in three ways.
1. Regular or Single Setting
In this type of setting, one tooth is bent to the left and the next tooth to the right and every fifth tooth is kept straight. This tooth helps in cleaning the metal particles from the slot. This type of setting has been shown in fig.
2. Double Alternate Setting
In this type of setting, two teeth are turned to the right and two to the left and one dent between them is left straight, which performs the function of clearing the metal particles from the slot.
3. Zig-Zag or Wave Setting
In this type of setting a few teeth are bent to the right and a few to the left. Thus it looks like a wave. This type of setting is done on blades of fine grade and superfine grades. It has been shown in fig.
Methods of Using Hacksaw
For the efficient cutting the following points should be borne in mind:
- Selection of hacksaw blade should be done according to the metal for which it is to be used.
- While fixing the blade on the frame it should be ensured that its teeth should cut the metal when they are driven forward.
- The job should be held in the vice in such a way that its cutting lines are clearly visible.
- Before starting a cut with a hacksaw blade, the blade should be kept on the marking line, the left-hand thumb should be placed with its support as shown in fig. It would ensure that the blade would move only on the line there would be no risk of its slip.
- After marking with the support of thumb we should hold the handle with right-hand palm and fingers and with the left-hand palm and fingers, we should hold the other end of the hacksaw frame as shown in fig.
- You should stand on the left hand of the vice and keep your right foot backwards and the left foot a little ahead of the right.
- Contact between the blade and the job should be in such a way that at least two teeth should remain in contact with the surface of the job.
- The speed of operating hacksaw should be 40 to 50 strokes per minute.
- Pressure should be exerted on the forward stroke and it should be withdrawn on backward stroke.
- Before finishing cutting with a hacksaw the cutting speed should be slowed down.
Precautions of Using Hacksaw
Following are the precautions of using hacksaw:
- Hacksaw blade should be fitted on the frame very carefully. It should not be very tight nor very loose.
- The job which is to be cut should not be held in a vice much high otherwise there would be vibrations in it.
- While cutting thin metal sheet, packing of wood, plastic or any other appropriate material should be used in its front and back.
- Hacksaw blade should not be allowed to become slanting while using a hacksaw. If it becomes slating, there are chances that it may break.
- If the blade starts cutting in a slanting manner we should start a fresh cut. Operating a hacksaw in an old cut may break it.
- If a blade gets broken while working, then we should replace it with a blade which has been used almost for the same period rather than using a brand new blade. The new blade can break if it is operated in that old slot.
- If necessary, water should be used as a coolant.
- After using a hacksaw either its blade should be taken out or it must be made loose.
That’s it, thanks for reading. If you have any questions about “Types of Hacksaw Frame” you can ask in the comments.