Dietzgen was one of the major US drafting and related supply companies, second to Keuffel & Esser. Their slide rules were a bit unusual, as they sold their own brand of rules, as well as rules made by many different manufacturers but branded under the Dietzgen name. Their in-house rules closely resembled those of their main competitor, K&E, and can often be mistaken for them. In fact, I've often seen cases and cursors from one manufacturer adorning rules from the other. Most of their rules were made on a mahogany core with celluloid facings, although they frequently strayed into other kinds of wood. They also sold a number of plastic rules made by various US manufacturers and Faber Castell (plus at least one Aristo that I know of). They also sold a number of aluminum rules made by the German maker Ecobra (also known as Eco Bra). Apparently, Dietzgen was their major customer, and eventually acquired them around the end of the slide rule production era. Dietzgen is one of the few drafting supply companies that has survived to this day ... but as a specialized paper and film product company (sadly, no more slide rules). Their rules remain popular with collectors, as many were of very high quality.
An older version of one of Dietzgen's top of the line slide rules. This rule has a few nice adaptions, like the slightly worn down edges of the celluloid on the griping regions of the slider (hard to see on the scans). This particular rule also features Dietzgen's frameless cursor design, and has a cursor patent date of 1946. Frameless designs were always more prone to breaking, and so relatively few survive intact to this day. They also weren't made for very long ... certainly by the early 50's they had switched to the more substantial all-metal designs. The case is virtually identical to the K&E models of the same era, with a hard black textured particle board body and leather closing flaps bolted on. First one I've ever seen for a Dietzgen rule, though. Overall, the condition of the rule is excellent ... a very nice example of a hard to find model.
One Dietzgen's best rules, still in incredible condition! Dietzgen's high end rules are frequently compared to that other major U.S. slide rule maker, K&E, which had very similar offerings. This model in fact is very close in design to the top of line K&E N4081-3, with the addition of an inverted DI scale on the reverse side. Like that later model K&E, this Decimal Trig Log Log rule also features relieved wood edges, though without the labelled celluloid laminate strip the K&E models sport. In fact even their cases are almost identical, featuring black leather bolted on to a hard cardboard base. The patina of this rule remains exceptionally white, and the wood seems to be mahogany (typical in K&E rules, but Dietzgen seemed to use a variety of materials, as shown below). This rule also features an all metal cursor arrangement, and has a more substantial feel than the K&E rules, although it does seem a bit dated in style. Judging from the various patent dates, this rule probably stems from the mid to late 50's, like the equivalent K&E model. Also included with this rule is one of Dietzgen's laminated inserts featuring a slide rule conversion table and trig sheet cheat, as shown in the high resolution scans. Clearly one of Dietzgen's best rules ... although I must admit I'm still partial to my favourite K&E N4081.
Another one of Dietzgen's high end celluloid/wood rules. In fact, this Vector Log Log Rule is identical in scale design and arrangement to the K&E vector model, the 4083-3. However, despite the stunning similarities there are also a few difference between these two classic vector slide rules. For one, the wood used here is not mahogany as in the K&E offerings ... it's much lighter coloured, yet definitely not bamboo either. In fact, if anyone knows what it is, please drop me a line! Secondly, the cursor has a variation of the classic Dietzgen closed metal design, with a laminate piece between the two substantial metal frames. Unfortunately, one of the cursor glasses is cracked on this rule. The brown all-leather case is also very similar to the equivalent high-end K&E case, although a slightly darker shade in this instance. A beautiful rule, nicely done, and difficult to distinguish from the K&E model.
As previously mentioned, most of the high end Dietzgen rules are very similar to K&E's, although they also produced a few unusual ones like this aluminum German-made 1738. Presumably supplied by the German rule maker Ecobra, this model invariably invites comparison to the rules of the predominant U.S. all-metal slide rule maker, Pickett. Generally, this Decimal Trig Log Log rule stands up very well indeed. Although I like Pickett's eye-catching/saving yellow, the finish of this rule is smoother and more nicely done. It appears to involve a coating of enamel or lacquer over the aluminum, which gives it a very nice finish. It would also seem to resists nicks and corrosion better that simple aluminum designs. This Dietzgen rule also features self-documenting scales - a brilliant adaptation generally seen only on European rules like those from Faber. The leather case has the trademark Dietzgen closing flap, which is actually a good idea if a bit dated in style. A very nicely done metal slide rule ...
Another example of an all-aluminum Dietzgen rule, undoubtedly made by Ecobra. This pocket slide rule is very similar in size and shape to my Ecobra 1461, although here with a duplex cursor assembly. This rule also has a lot of nice extras, like the oversized slider, multi-colour scales, Pythagorean scale, and multiple hair-line cursor. Can't figure out why they didn't include that last feature on the 1738 above. The case is virtually identical in design to my Ecobra 1461, although this one is a stained a darker colour and has the name "Dietzgen" stamped on the front and "Germany, U.S. Zone" on the back, helping to date this rule to just after the Second World War. Probably one of the first Ecobra rules Dietzgen ever started carrying (see my Misc page for a discussion of a Ecobra's relationship with Dietzgen). A very nice and useful pocket model rule.