ProDrill™ DTH Hammer's repair kit ( E-Kit ) including top sub , external cylinder, guided sleeve, drive chunk, Generally speaking, the external cylinder can be replaced after it is worn out, but we do not recommend replacing the external cylinder. Replacing the outer cylinder is very troublesome. Because our DTH hammer is not so high cost , one set of E-Kit cost is 50% of one new dth hammer , it is more cost-effective to buy the new one hammer directly.
The efficiency and power of replacing the external cylinder are slightly worse. The drilling speed of replacing the external cylinder is not as fast as the original one. There are other uncertain factors, such as the time to disassemble DTH hammer and the time to clean it. this is what we have to explain it to our client at time of their buying and using Repair Kit ( E-Kit ) .