Original Item: We have found a few very scarce tools for the Lewis Mk I Light Machine Gun as used in the First and Second World Wars. "Spanner," in American English, means "wrench," of course. This tool was designed to perform either two or three functions, depending on which model spanner. The first model was intended for removing the barrel mouthpiece, which is a funnel-like piece that was critical to pulling cool air over the radiator cooling fins. This spanner was also used to unscrew the gas chamber from the barrel band.

Very soon after the gun and spanner were introduced, the spanner was recalled and a notch, 0.25 x 0.125 inch, was cut in the handle end of the tool. This notch functioned as a wrench to remove a tiny square piece called the locator stud from the barrel casing clamp. Since this notch was a tight fit into the clamp ring, some spanners were modified by beveling the handle on both sides of the notch. This gave more clearance and made the tool easier to use.

Although all spanners were supposed to be recalled for the modification, a few of them were missed. IMA has some of these and also some of both modified versions. All spanners are clearly marked with the BSA logo of three stacked Martini-Henry rifles with bayonets.