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Fig. 16.1 shows a precision steel roller chain to be installed
on drawworks transmission. These are manufactured in single,
double and multiple widths and a variety of chain pitches.

Figure 16.1 – 1. Outer plate, 2. Inner plate,
3. Pin, 4. Bushing, 5. Roller

Lubrication of roller chain, as shown on the API graphs,
becomes more critical as speed increases. On most high speed
drilling rig drives it is advisable to provide force-feed lubrication
to the chain from the inside of the drive so that centrifugal force
will throw the lubricant through the chain and not off the chain.
Some designs now introduce the lubricant into the sprocket
through the shaft and thence out the root diameter of the sprocket
into the chain. Actual lubrication is extremely important to good
chain life and the recommendations of the manufacturer should be
followed as closely as possible. Particularly troublesome have
been such items as the incorrect oil; lack of oil, or clogged lines
resulting from dirty filters, and sludge or rags and soft rope getting
into the system.
During installation the alignment of roller chain .drives
should be rechecked. Also some slack should be allowed on one
side of the chain, preferably the lower side. A pretensioned drive is

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