Proper lubrication of the P1 HDD hammer is the most important and least expensive maintenance item on the hammer and drill rig. Testing hammers without lubrication has proven that in less than one minute of drilling , temperatures of the piston surface can exceed 1400º F (752ºC) and temperatures on the bit splines can reach close to these same temperatures. These excessive temperatures generate heat cracks (fine cracks) on the surface finish of the piston and bit splines that may spread through impact and cause piston and or bit breaking.
This also occurs as a result of high temperatures which greatly reduces the tensile strength of the material allowing fractures to initiate.
Air, water and most of the drilling fluids and polymers are all corrosive.
Rinse the hammer thoroughly upon completion of the bore. The most detrimental type of corrosion encountered in a hammer is oxidation cavitationfinite notches in the material surfaces) this happens when the hammer is in storage and has not been well lubricated. When finished drilling with polymer /foam mix, it is necessary to rinse the entire hammer inside and out with fresh clean water and lubricate properly. Prolonged exposure to the atmosphere creates a corrosive reaction between the steel and polymer/foam mix. Corrosion stress is a common cause of drilling tool failures.
Contamination from foreign material entering the hammer is the second most common cause of hammer and bit failure. Foreign material enters the hammer from water that is not filtered, dirty drill rods, dirty water tanks and contaminated air filters on compressor. When water that is used from any source especially a natural body of water it needs to be filtered,water tanks need to be inspected and rinsed out, if the air filters on the compressor are dirty replace immediately.
Naturally occurring micron particles are present in all streams of water and originate from rocks and sediment in streams through natural decomposition and also industrial, agricultural, and domestic activities around streams of water. If water from a stream is used in a hammer it needs to be filtered as fine as possible. The microns can have a sand blasting effect on the internal parts of the hammer resulting in sever worn parts and possible failure of those parts, this is known as high velocity erosion. If possible use water from a public source (hydrant) and you should filter it also.
Clean Air Delivery
The hammer relies on a supply of clean lubricated air to operate reliably. The hammers piston has a close tolerance fit with the case bore and cycles around 2500 blows per minute. Failure to ensure that a clean lubricated air supply is being provided may result in overheating, material pick up, seizure or failure. Hose ends should be covered when not in use and the hose from the support pack to the drill should be used only for that due to to oil residue in the hose.
Clean Drill Rods
Drill rods can become contaminated when used with drilling fluids, even in a short period of time. These can usually be blown out prior to completing make up, just be sure to cover the end of the other drill rod that is in the vise prior to blowing them out. Drill rods that have been sitting for a while may need to be brushed out using a small round steel wire brush, by pushing and pulling it back and forth through the drill rod.