Industrial chain

Pitch is the distance from the centre of one pin to the centre of the next. Measure it with callipers. 12.7 mm means 08B or 40, 15.875 mm means 10B or 50, 19.05 mm means 12B or 60, and 25.4 mm means 16B or 80.

They share the same pitch but differ in roller diameter and inner width. The A series (40, 50, 60 and so on) is the American ANSI standard; the B series (08B, 10B, 12B) is the European ISO/DIN standard. A sprocket cut for one will not seat properly on the other.

When it has stretched. Measure ten pitches and compare with the nominal length; at about 2 to 3 percent elongation it is time to replace it. A stretched chain rides up on the teeth and takes the sprocket with it.

No. Stainless is only needed where moisture, cleaning chemicals or food come into contact with the chain. Its tensile strength is lower than carbon steel and it costs more.

Breaking load, the force that parts the chain, rises roughly in proportion to the number of strands. Allowable power in continuous duty does not: the load never splits perfectly evenly between strands, which is why the standards apply a factor of about 1.7 for duplex and about 2.5 for triplex.