Piston Groove Top Nut Piston nuts are made of various materials, depending on their strain and purpose. We can manufacture piston nuts for various piston rod sizes and designs. You May LikeCompressor Piston RodReciprocating Compressor CylinderPeek Valve PlateCompressor Discharge ValveCrosshead PinReciprocating Compressor CrankshaftConnecting Rod Bearings