SINGER 6610 - Manual (Page 46)

Lubricatìngi the machine
How often you need to lubricate the machine
depends on how often you use it and where
you keep it. The following general guidelines
assume that you will be sewing several times
a week. But if you use your machirie more
frequently, lubricate it more often than the
guidelines suggest.
Approximatiey once a year, lubricate all
moving connections, as shown, to ensure
freedom of movement and to protect metal
parts from excessive wear.
To determine which connections move and
need lubrication, turn the handwheel slowly,
by hand, while face plate is removed.
When lubricating, apply only SINGER* oil at
the points shown. SINGER oil is specially
prepared and does not contain harmful
deposits that can interfere with the smooth
action of precision parts.