Because the original spring-loaded screws (as seen in photo) are so often missing or displaced from the old Singer Pinking Attachments, we now have available a special-sized screw that has proper length and fit and can be used as a replacement. To attach the Pinker securely to the machine’s presser bar, a small tightening wrench is included. Because of the abnormal thread pattern Singer used for all of their machine products and screws, standard screws from hardware stores do not fit properly. It has taken several years of searching, but April 1930’s has finally found a proper-fitting screw with the same thread-pattern and pitch to be used as a replacement for the Pinking Attachment.
A proper thumb or presser bar screw is necessary, whether it be the original spring-loaded thumb screw that accompanied all Singer Pinking Attachments, or one of these properly-fitting after-market screws with tightening wrench. The attachment is quite heavy and a proper screw helps maintain the balance for appropriate fit. You can see the difference in design of the original Pinking Attachment screw versus a normal thumb screw in one of the photographs above - you do not want to use a regular thumbscrew because it is not long enough to support the attachment properly.