What Should You Know Before Buying Air Chisel Bits About Type & Size?

An air hammer / air chisel used with air chisel bits is a powerful, high-impact combination. It uses compressed air to drive an internal piston, striking the back end of the chisel thousands of times per minute. This allows cutting, breaking, and separating work that would be difficult to do by hand to be completed much faster.

Tien-I mainly produces air chisel bits in two shank sizes: 0.401" and0.496". The main reason for these two sizes is the difference in working load and energy transfer requirements.

Below are the key differences between these two specifications:

0.401" Shank
This is the most common standard size and is suitable for most light- to medium-duty applications. Because the shank is smaller, it is better suited for transferring high-frequency, medium-impact energy.

0.496" Shank
This size is designed for heavy-duty applications. When the air hammer has a longer stroke and delivers higher impact force, a 0.401" shank may break due to metal fatigue under heavy load. The larger cross-sectional area of the 0.496" shank allows it to withstand stronger impact force and helps prevent damage under demanding working conditions.

In addition to shank diameter, the shape of the shank may also vary depending on user habits in different countries or specific application needs:

Round Shank
Allows the chisel bit to rotate inside the chuck, making it suitable for jobs that require frequent adjustment of the cutting angle.

Hex Shank
The 0.401" size is also available in a hex shank version. Its purpose is to lock the chisel bit in position and prevent it from rotating during operation. This is ideal for cutting applications that require accurate direction control, such as cutting sheet metal along a specific line.

Non-Turning Shank
Designed with special grooves or shoulders for quick-change retainers. This helps keep the chisel securely in place during operation.

In addition to the most common 0.401" and 0.496" sizes, air chisels — or more broadly, pneumatic breakers and rock drills — are also available in other sizes. These specifications are usually determined by tool size, impact energy, and industry standards.

Type	Shank Diameter	Common Shape	Main Application
Micro	0.300"	Round	Detail work, adhesive removal
General Purpose	0.401"	Round / Hex	General auto repair, sheet metal work
Heavy Duty	0.496"	Round	Heavy machinery, industrial teardown
Industrial Grade	0.580" / 0.680"	Hex	Rivet removal, casting cleanup
Pavement Grade	1-1/8" 以上	Hex	Road breaking, construction demolition

In addition, Tien-I focuses the durability development of its air chisel bits on theshank / collar end, rather than only on the working tip of the chisel.

Below is a detailed explanation based on the information shown in the image:

1. Shifting the Stress Concentration Point

From the color comparison in the image:

Traditional Design
The collar area of the chisel is designed with a 90-degree or near-right-angle shoulder. When the air tool impacts at high speed, stress becomes concentrated at the sharp corner marked in red. This is known asstress concentration. Under repeated impact, this area is the most likely to develop micro-cracks and eventually break.

 

New Design — Air Chisel 2.0
Tien-I redesigned the collar area with a sloped, rounded profile. This allows the impact energy to spread more evenly across a larger surface area, shown in the green area of the image. The stress heat map shows a more balanced energy distribution, greatly reducing the risk of fatigue failure at a single point.

Why is the shank end more important than the chisel tip?

The chisel tip, or working end, will naturally wear down over time. This is considered normal wear and can often be repaired by grinding.

However, if the shank end breaks, the entire chisel bit becomes unusable immediately. It may also damage the air tool itself. Broken pieces left inside the bushing are very difficult to remove and may cause damage to the air hammer. This also increases safety risks. At the moment of breakage, the broken part may be ejected due to the high-speed reciprocating motion, potentially causing injury to the operator.

In addition to improved durability, Tien-I also produces air chisel bits with a wide range of tip shapes. Below is a comparison of common chisel tip types and their functions:

Chisel Type	Visual Feature	Main Function
Flat Chisel	Flat cutting edge	General cutting, scraping, bolt removal
Spot Weld	Special concave cutting edge	Separates automotive spot welds without damaging the base metal
Tailpipe Cutter	Double cutting edges with a guide groove	Quickly cuts round tubing in a circular motion
Pickle Fork	Two-prong fork shape	Removes ball joints and tie rods from automotive chassis
Punch	Slim round pointed tip	Drives out pins, rivets, or marks positions

To better understand how air chisel bits are used in real applications, please refer tothis YouTube tool demonstration video.

In addition to the chisel tips listed above, Tien-I also manufactures many other types of air chisel bits.Please visit the official website for more information.