From alloyartifacts Blackhawk page 6
Early 6218 9/16 Nut-Holding Speeder Socket Wrench
Fig. 38. Early Blackhawk 6218 9/16 Nut-Holding Speeder Socket Wrench, with Inset for Markings, ca. 1919-1920.
Fig. 38 shows another early specialty tool of unusual design, a Blackhawk 6218 9/16 speeder socket wrench with a second socket on a sliding extension. As can be seen from the photograph, the basic tool operates as a fixed-socket speeder wrench, and the sliding extension carries an additional holding socket.
In use, the sliding extension was pushed out and slipped over the bolt head, and the spring then held it in place while the speeder loosened or tightened the nut.
What was the motivation for this tool? Certain service jobs required turning nuts on bolts that were not secured by other parts, so that the bolt would need to be held while the nut was turned. Since a speeder wrench really needs two hands for efficient operation, placing a bolt-holding extension on the shank allows the speeder to work, well, speedily.
The idea for this tool actually goes back to Walden-Worcester, who noticed that the rather obscure patent #1,164,815 for agricultural tools could be adapted to automotive use. Walden's version of this tool was built as an extension adapter that could be bolted onto a standard speeder, and an example can be seen as the Walden-Worcester 6418 Nut-Holding Extension. Incidentally, Blackhawk's copying of Walden's idea became one of the claims in a lawsuit filed by Walden.
The catalogs recommended this particular tool for Model T engine base bolts, but there were probably many other applications as well. Blackhawk also made a similar 6216 model with a 1/2 socket, which was recommended for Model T rear axle service jobs.
