1. When the hammer drill bit gets stuck in concrete or masonry, the tool to start twisting which might cause operator’s hands to be sprained.

2. It requires different impact rate in drilling and chiseling, drilling works requires high-frequency impacts converted from motor power for better efficiency.

3. Drilling works are sometimes performed in hot and humid conditions, which would require better cooling performance, in order to prevent motor from overheating damage.

1. Rock drilling works are usually performed in wild conditions, where voltage of power supply and environmental temperature are unstable, and rocks are usually very hard. Rotary hammers are required proper flexibility and adaptability to satisfy the needs.

2. Rock powder granules are very tiny, can easily invade device switches and oil seals, cause switch malfunction and oil leak.

1. Drilling and chiseling requires different impact capacity performances, chiseling work requires most motor power converted into impact power to achieve better demolition efficient.

2. Wall chiseling produces powder of which granules are very tiny, can easily invade device switches and oil seals, cause switch malfunction and oil leak.

3. Cylinder and chunk can be easily damaged in wall chiseling, since they are required to bear massive impact force and vibration, there linking parts can be easily damaged.

1. Large scale demolition chiseling hammers usually features low durability due to parts damage caused by heavy vibration at works.

2. Chiseling works are usually performed in hot and humid conditions, which would require better cooling performance, in order to prevent motor from overheating damage.