Ingersoll made a simple twist filler designed to be inexpensive. The original ones were metal, but still managed a gold nib. The simple and cost effective filling system was a twist filler. The sac far end is cut off to make the sac a tube. A small plug of hard rubber is inserted into the far end that has been cut off. At the end of the barrel is a small hole. A standard furniture tack is passed through the hole and into the hard rubber plug. Now you can twist the sac in either direction and around and around all you want!
Shown is a celluloid version. Some of the larger celluloid versions had a blind cap to cover the tack, but most were just exposed with no cover and no locking mechanism.
I owe my readers pictures of a disassembled Ingersoll. For now, the tack on the end will have to do.
