Pneumatic Tools Lubrication Methods

By 9 June 2018

There are three methods of lubricating pneumatic tools:
• Integral oil reservoirs and feed devices
• Air-line lubricators
• Manual oiling arrangements

The reservoir has to be topped up every shift and is therefore dependent on the human element, which is its main drawback; so it is recommended that, in addition to this kind of built-in lubrication, an air-line lubricator be used.

Manual oil arrangements are seldom satisfactory. They consist of merely pouring oil into the inlet connection and hoping that a sufficient quantity will find its way to the working parts. In practice there is either too much at the beginning or too little at the end. But there is a more fundamental objection to this kind of lubrication. For air lubrication to be satisfactory, the oil must be present in the form of mist particles, so that it can be carried along through the pipes and hoses. Particles larger than about 2 um tend not be carried along as a mist but are left deposited on the inner surfaces of the distribution system. So an ideal lubricator needs to inject fine droplets in the air stream, which are carried along with the air rather than deposited on the surfaces.

Irrespective of the method of lubrication chosen, an indication of the correct oil feed can be obtained by examining the exhaust air. It should be possible to see a faint oil mist at the exhaust port but no more. On a rock drill or breaker, the exposed portion of the drill steel should be covered with a thin oil film but no more. If the steel is wet with oil or if the outside body of the drill is covered, the amount of oil feed should be reduced.