A mahogany and celluloid Keuffel & Esser slide rule. A 'Polyphase', type N4053-3. Similar to the Rietz system, but with small differences on arrangement and how the S and T scales are done. The S is linked to the A scale rather than D scale and the mantissa scale L is at the back of the slide instead of the front.
Complete with its 4053-3S leather protective case and including the instructions on adjusting. This adjustment mechanism with screws is what the patent number on the stock is about. The metal strip protecting the edges of the strap has US patent number 2,000,337 stamped on the edge. Now without that hint, would never have spotted the ingenious locking strips for the tongue underneath.
These K&E are probably very common across the pond, but relatively rare here. Curious for this one and it looked clean in the pictures, so went for it. It indeed is clean, however the plastic slideblocks of the cursor are cracked and the spring very rusty. This seems to be a standard fault with these, the celluloid disintegrates with time. The lower slideblock was also warped a bit, skewing the cursor a little. The cursor screws are corroded and won't budge, but some shimming with strips of thin adhesive paper label inside the slideblock brought it back perpendicular to the scales.
The top cursor slideblock also notes it is patented. Reading the claims, patent protection for rounded corners also happened back in the thirties.
Another unexpected item was that the sine scale is half a millimeter or so off. The celluloid window for the S&T scale on the slider is a bit loose or perhaps warped. Other than all that; it is still straight and serviceable!
It's rather short and light, compared to e.g. some German slide rules. The cursor even partially slides off the ends at the index positions. Single line cursor also and no C markings. Clean and compact.
From online resources, the serial number puts this slide rule as produced in 1943. (The amount of resources online on sliderules is astonishing, by the way. On the internet, there really is no subject so 'niche' that it doesn't have its collectors society.)
How does a '43 slide rule end up in Holland? Come to that, hadn't realized that slide rules continued to be produced throughout the war - essential tools. (Not consuming too much important raw materials either, may have counted as well.)
Did this little engineering tool come over with allied forces? Or was it perhaps part of Marshall plan items sent over? Or was it just simply exported and sold here after the war from stock. (The here more common makes were not producing much right then, I suspect...)
Analog technology and again a snippet of history :)
Yay, slide rules! That's an attractive one - much older than the ones I've found. That bit about "no niche too small" is very, very true :DReplyDelete