The last thread on this is too old to post in. Thought that I would revive the subject though.

Cory made their Rubberless coffee makers in three sizes. The DNG Petite Rubberless 4 cup using DNU upper and DNL lower. The DCG Royal Rubberless 8 cup Royal Rubberless using DCU and DCL glass parts and the DIG Imperial Rubberless 12 cup using DIU upper and DIL lower glass. Based on advertisements they appeared after the war rather than being a war time attempt to save rubber. The earliest advertisement I have seen for them is 1947ish and the last from a 1955 wholesale catalog.

I have working units in all three sizes. Recently there has been some glass parts on ebay but be aware that the carafe neck is a unique size so clamp bands for the handle to carafe mounting is also unique so far as I know. Standard Cory clamp bands as used on their rubber gasket sealing vacuum coffee makers are too large in diameter for the neck of the rubberless units.

Currently I am seeing complete 8 cup rubberless units frequently go for less than the cost of a Bodium or Yama similar size vacuum pot. Some of the best buys are from units poorly listed by people who are selling items they know little about so they fail to mention the "Rubberless" word. The 4 and 12 cup sizes are a lot rarer generally than the 8 cup brewer. The Yama all metal screen filter for the 8 cup Yama stove top unit will work with these old Cory's as will the Silex ceramic Flavor-Guard filter among others. Many Hario filters are too large in diameter as they are designed for flatter funnel bottoms and shorter vacuum tubes than are found in an 8 or 12 cup Cory Rubberless brewer.

I also like the old all stainless steel Nicro vacuum brewers as they are virtually indestructible and do a very good job IMO. No worry about glass breakage.

The BAHarris site shows a 1941 patent drawing for the "Rubberless" brewer and claims that the patent was submitted in 1942 here: http://baharris.org/coffee/History.htm

Here's a picture of the Cory "Royal" Rubberless: http://baharris.org/coffee/Vintage/CoryRubberless.jpg

The BAHarris Vac Pot page remains a valuable resource. http://baharris.org/coffee/VacuumCoffeePots.htm