If you have a 319, here is a
pull down and rebuild guide from Miriam. Very picture heavy.
Here's
another thread started by Great White who had just acquired a 319.
If you have a 320, 319, 306 or 206, do not use ordinary domestic (15x1, 2020, 705) needles. They are too long and may strike the bobbin case when using heavier fabric. The latter three machines use different bobbin cases. The 306 and 319 look almost identical but they are different in many ways. The 319 and 320 use the same bobbin case.
Looking for a manual?
319K manual from Singer
306 manual from Singer
206 manual from Singer
206K25 manual from Singer
Singer is quite generous with manuals for their older machines and allows free downloads provided they have it as a pdf. These are printable yourself or they can send you one for a fee (type the model number into
their search page).