I was recently consulted about a situation where the glass-reinforced nylon, rod guide-bush in a hydraulic cylinder was scratching the hard chrome plated rod. So in effect, the guide-bush was harder than the hard chrome plating. And this should NOT be the case. In other words, the hard chrome plating on the rod was soft. Or more correctly, not hard … Read more

Pipe threads are a lot like suction strainers in that they have no place in a modern, properly designed hydraulic system. HOWEVER, pipe threads are a legacy item, and as such, are still a feature of many (too many) hydraulic systems still in operation today. So every hydraulics user needs to know about them.

National Pipe Tapered (NPT – U.S.) … Read more

The term pilot ratio refers to the ratio of two, discrete areas of a piston, spool or poppet on which opposing pressures act. The pilot area, on which pilot-pressure acts, is always the larger of the two areas. Working or system pressure acts on the smaller, opposing area. This means a relatively small pilot-pressure can overcome a much larger working … Read more