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detrimental to both chain and shaft bearings. However, excessive
slack is also harmful due to chain whip and possible tooth
disengagement. On long drives it is sometimes possible to remove
a link to shorten the drive if stretch-wear provides excessive slack.
The chain should, of course, be kept as clean as possible and
washed with solvent if it should be subjected to grit or dust; after
washing, the chain needs to be relubed.
Worn sprockets should be replaced, if possible, or reversed
so that the chain is not hooked by workteeth. If it becomes
necessary to use less strands of chain on a drive designed for a
greater number of strands it will be necessary to replace or reverse
the sprockets when the full multi-strand chain can he obtained and
installed. This requirement results from uneven tooth wear and the
resulting unequal load on the multi-strand chain.

Silent Chain

Silent chain types of drives combine some of tin-features of
both roller chain and gear drives. In comparison to roller chain the
silent chain-type now utilizes gear teeth-type sprockets and a semi-
articulating mesh action.
Along with their quieter operation, silent chains may be
considered to be adaptable to higher speeds than roller chain
drives. However, silent chains require very good shaft alignment
and very rigid installations. As they also require a tighter drive
with less slack than roller chain it is often necessary to utilize take
up type installations on long drives.
The general maintenance lubrication procedures mentioned
in regard to roller chains are applicable to silent chains. However,
one trouble with such chain is its lack of standardization and, as a
consequence, each chain manufacturer should be consulted in
detail for the lubrication and maintenance instructions concerning
his specific product.

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