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Before beginning to drill, there are several factors that must be taken into consideration in order to select the appropriate down hole hammer. Consider the following:
- Hole Size: In most instances, the outside diameter of the hammer closest to the hole size being drilled should be used for most efficient drilling. This reduces the instance of hole collapse and makes cleaning the hole easier. One needs to take into account that there must be sufficient annular area around the hammer to pass the drilled cuttings. This normally will supply the most efficient operating conditions. The Hammer Selection chart below displays Numa hammers and their corresponding bit range
- Air Consumption: The amount of compressed air available must be taken into consideration when using a down hole hammer. Some hammers perform better than others on specific air packages. Be sure to refer to the Air Consumption chart or your maintenance manual for the proper air consumption for each hammer.
- Rig Capacities: The larger the bit and hammer, the greater the rotational torque and feed/pull back requirements become. Do not exceed the drill rig's capacity. Please consult your drill rig manufacturer with any questions on rig capacity.
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