I really love the Hemmi bamboo slide rules (they have my vote for the best overall construction and “feel"), and I’ve collected a number of them. Many of them have a model number prominently displayed somewhere, and are therefore very easy to identify. For the rest of them, the main resource I have is Paul Ross' magnificent Hemmi catalog — with which I’ve been able to positively identify almost all of my Hemmis.
This is one of the exceptions (click on the thumbnail at right to get a large 300 dpi scan). The scales are identical to a Model 1 and Model 47, but it has some of the characteristics of each. For instance, it has pins at the ends of the stators and the slide, like the Model 1. It has a cursor of the same general style as the Model 47, except it’s considerably wider. Like them, it has 250mm scales.
It’s entirely possible that the slide rule originally had the model number on the paper glued to the back. Unfortunately, that paper has been rather completely destroyed. So I’m left mystified, a state that my wife would tell you I’m all too familiar with.
One strange note: the former owner of this slide rule decided to add a few gauge points of his own. Look closely at the C scale and you’ll see 'em…
If anyone can identify this, please leave me a comment here…