Above and at left, we have a Nikkei 200 ( the top rule in both scans) and the very same above 260. Note that these rules use a metal back, with 12 pins, fully covering the bamboo underneath. Totally unlike Relay rules. Also note that instead of having labels glued to the backs of the rules, the tables are printed directly on the metal backs in black ink.
These tables differ greatly between the two rules, that at top above, on the "folded" scale type, listing many conversions with the center index of the CF scale set to a number on DF. The 260 has a more normal table on it. Also note that the trig info differs as well.
These 8 inch rules are a handy length, but are very light in weight and rather thin. Not a feeling of flimsiness, but nearly so. Perhaps this is one reason that not many exist today. They smack of inexpensive construction, and here I mean inexpensive, but not necessarily cheap. They work, and these few have survived.
One interesting side note: the manuals both give info on scale usage, but clearly state that rules with folded scales have them folded at PI. But our 200 here has sq. root of 10 folded scales, an older style. Wonder why? Me too. Also, the manuals make no mention of any log-log or special hyperbolic scales, odd since one of the manuals came with a 510!! |
