Slow-Speed Drives. Because slow-speed drives are not
usually enclosed, adequate lubrication is difficult. Heavy oil applied to the outside of
the chain seldom reaches the working parts; in addition, the oil catches dirt and grit and
becomes abrasive. Soak exposed-type chains in a recommended lubricant to restore
lubricating film. Remove excess lubricant by hanging the chains up to drain. Do not
Dust and grit combine with lubricants to form a cutting compound that reduces chain
life. Do not lubricate underwater chains that operate in contact with considerable grit.
If the water is clean, lubricate the chain with the recommended lubricant with a brush
while the chain is running.
Medium-Speed Drives. Continuously lubricate medium-
speed drives with a drip- or sight-feed oiler. The lubricant type depends on
High-Speed Drives. High-speed drives should be
completely enclosed in an oil-type case and the oil maintained at proper level. Oil type
depends on temperature conditions. Drain the oil and refill the case to the proper level
according to the manufacturer's recommendations.
Clean and Inspect
On enclosed types, flush the chain and enclosure with
kerosene. On exposed types, remove the chain. Soak and wash it in kerosene. Clean
the sprockets, install the chain, and adjust the tension.
Note and correct abnormal conditions before serious
damage results. Do not put a new chain on old sprockets. Always replace old
sprockets when replacing a chain. Old, out-of-pitch sprockets cause as much chain
wear in a few hours as years of normal operation.
Troubleshooting. A troubleshooting checklist for chain drives is
included as Table 48.