In building the Bentley BR2, one comes upon components like the crankshaft, and maneton shaft which feature mating tapers. In the more general workshop context, these are frequently useful for applications such as tool location, also for taps for coolant or gas. Often in the past, various esteemed authors have recommended that for such workpieces, the topslide should be set, and both the internal and external taper features machined without disturbing the setting. This is of course an ideal approach, which will ensure that the mating parts do indeed fit. I felt that as one of the lesser mortals, it was highly likely that my job planning would be imperfect, and that Murphy would intervene (and he did), forcing the topslide to be reset for another job between making the mating components. The question then became one of how to set over the topslide to a specific or at least accurately repeatable angle. I recalled reading two letters to Scribe a Line, dealing with the subject of quickly setting a milling vice square to the table. One came from Mr John Wilson (issue 93) the other, I have not been able to identify. In each case, the vice, gripping a bar or setting tool, was moved until contact was made with stops which ensured correct positioning. I also considered the approach advocated by Will Bells (issue 106 page 12 ) which employed a DTI check at spaced marks on the topslide, but on balance felt that the time spent in making the gadget given here would probably be repaid in speedier setting. Given that most machine shop devices had been pretty well thought out by about by the year 1900, it is unlikely that something similar has not been concocted before, its just that I haven't seen it.
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