letter scale

The maker of this stately chrome letter scale mounted on a beautifully cut glass plate is unknown to me. I guess this scale comes from Germany, but it could also be England. A brass version of this scale model, together with a stamp humidifier and stamp box mounted on a black glass plate, has been shown before, see here and bottom right of this page. That copy has the ROWENTA brand name on the bottom of the back. Presumably the Rowenta letter scales were purchased elsewhere and provided with the brand name ROWENTA [name taken from RObert WEiNTrAud]. There is only one own design letter scale known from Weintraud and patented, see this one Weintraud.
The mechanism has a rack and pinion that moves a gear or pinion on the pointer axis. The mechanism has two tension springs. The pointer can be set to zero with the rotary knob on the left side, turning the knob tightens the left tension spring more or less and thus changes the position of the parallelogram mechanism and the gear rack attached to it, which in turn changes the position of the pinion, thus the position of the pointer changes slightly. The dial has a stripe for every five grams. The weighing range is 500 grams, indicated here in German with GRAMM. After a long search I found an image of this model in an advertisement in a newspaper from the Netherlands Indies, namely in De Sumatra Post of September 26, 1927, see bottom of this page. That specimen weighs up to 16 ounces (= 453.6 grams).
The letter scale was disassembled, cleaned, dedusted and the rust was removed, and reassembled. The letter scale is visibly refurbished, the chrome is shining again. The glass plate is 10.3 x 5.7 centimeters, the scale housing measures 7.4 x 3.4 x 10.0 cm, the scale is 15.0 cm high. The diameter of the letter tray is 6.6 cm. Below are some more images of this rare letter scale.