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ray -- I'm pretty sure that the WB-in-a-Diamond trademark was that of Whitman & Barnes. The last I heard of Whitman and Barnes, they had gone from being a hand tool maker to a cutting-tool specialist, making drills, taps, and dies. I'm not sure if W&B is still in business or not. I don't have any idea about the Anchor & Circle mark. As the others have indicated, the sizes stamped on the wrenches are the sizes of the bolt (nominal thread diameter) that the wrench opening fits, and since the wrench opening must be slightly larger than the bolt head, and the bolt head must be quite a bit larger than the bolt thread, the openings will be significantly larger than the size. This sizing methodology was not only used for British Standard sizes, but for some old US standard wrenches also. Bolt heads are sized by a variety of formulae under a variety of different standards . . . here in the US before WWII, the common head sizes were (1.5 times thread diameter) for most fasteners and for US Heavy fasteners it's (1.5 time thread diameter plus 1/8 inch). The English used a different set of formulae, which I have forgotten, but it resulted in some sizes that seemed really odd to those of us familiar with the US standards . . . but the English did design their fasteners so that the same-size wrench OPENING could be used on different-series fasteners. Thus, you have a single wrench opening that fits both a 3/16 inch British Standard Whitworth fastener and a 1/4 inch British Standard Fine [thread] fastener. (I suspect that you've misread the wrench or that it has been damaged enough to make reading difficult; I'd just about bet that the "B5W" you cite is in reality "BSW".) During WWII the US, Canadian, and British government worked to develop a new standard thread system that would be used by all 3 countries for war goods. This standard, the Unified Standard, went into widespread use in the US for inch-sized fasteners, and is still used today. I believe that as a part of the Unifed Standard agreements, we modified our nut-and-bolt sizing system to increment larger head sizes in 1/16 inch steps rather than the earlier 1/32 inch steps. You may remember some of the now-oddball wrench sizes that were once common, 19/32 inch, 21/32 inch, 25/32 inch, and 31/32 inch come to mind almost immediately . . . and some of these sizes are still catalogued by the major US tool makers simply because there are still people working on pre-war equipment. To illustrate the head-sizing formulae, consider first a 3/8 inch bolt; the "normal" bolt-head and nut size is 3/8 inch X 1.5 = 9/16 inch, while the US Heavy nut is 3/8 inch X 1.5 + 1/8 inch = 11/16 inch. For a 1/2 inch bolt, the "normal" bolt head or nut is 1/2 inch X 1.5 = 3/4 inch; the Heavy head is 1/2 inch X 1.5 + 1/8 inch = 7/8 inch. I'd guess that the predominant application for the smaller sizes of US Heavy nuts today is in machine shops and larger manufacturing plants, where they are used extensively on "jigs and fixtures". The larger sizes of US Heavy nuts are used when making up bolted-flange pipe joints, and here I'd guess that refineries and process plants are the big users. More than you wanted to know, right? John
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