Full service of a very nice example of the Waltham Vanguard Model 1908.
Some may wonder what was meant by the “TERMINAL HAIRSPRING” wording in the winding wheel. This refers to the extra room or “air” around the first turn of hairspring around the center (see picture below). This was meant to improve the watches performance throughout the 24 hour wind. The mathematical theory was sound, although it may have been more of a marketing idea (especially as it was conspicuously marked on the movement). The actual improvement probably was minimal.