As with builders’ screws, the primary function of coffin screws was to secure key elements of the coffin together. But unlike builders’ screws, coffin screws had decorative heads that were designed to be exhibited, rather than hidden.
Coffin screws had a traditional iron screw shank with a large slotted head used for tightening. The length of the shank on these screws normally ranged from between 1¼ inches to 2½ inches. Newman Brothers sold them by the gross. See catalogue image below for the range of coffin screws produced at the manufactory.
As Thumbscrews had the added bonus of giving leverage when tightening, as well as providing assistance with moving the coffin, they were often favoured in place of coffin screws.