Known Bloch Schnellkalulators
| Serial Number | Patent Data | Ownership | Picture | Reference |
| 327 | DRPa | ? |  | Rechnerlexikon |
| 478 | DRPa | ? | Rudowski1 | |
| 1049 | DRP | ? |  | Sold by http://Antikma.de 2011 |
| 1144 | DRP | Wolfgang Irler |  | Rechnerlexikon |
| 2178 | DRP | Jim Falk |  | Calculant |
| 3211 | DRP | Werner Rudowski | Rudowski | |
| 3318 | DRP | Instituto Montani |  | Museo Virtuale |
| 6197 | French | ? |  | Sold by “Wormel” on ebay, June 2012 |
Very rough dating
On the issue of dating, from the above we can identify that serial numbers 327 and serial number 478 (mentioned by Rudowski) are stamped “DRPa” (Deutsches Reichs-Patent applied for) whereas serial number 1049 (sold by Antikma.de in 2011) is stamped DRP (with the patent now approved).
All subsequent serial numbers including 1144, the present Calculant object (serial number 2178), one owned by Rudowski (serial number 3211) and serial number 3318 are stamped DRP. One designed for the French market (serial number 6197 and sold by Wormel on ebay in June 2012) is clearly much later. One other was sold on ebay in 2008 but details are not yet available.
Assuming a reasonably slow startup in demand, assuming that production began when the first patent was applied for (since it cannot be earlier), and knowing that the patent was granted in 1922 gives as a guess the table below which is at best suggestive of a date for this machine (Nr 2178) of around 1924–6
| Date | Sold | Highest Serial number | |
| 1919 | 20 | 20 | DRP Applied For |
| 1920 | 100 | 120 | |
| 1921 | 300 | 420 | |
| 1922 | 450 | 870 | DRP Granted |
| 1923 | 650 | 1400 | |
| 1924 | 800 | 2220 | |
| 1925 | 1000 | 3220 |
1 Werner H. Rudowski, “The Schnellkalkulator ‘System Bloch’ ”, The Journal of the Oughtred Society, vol. 14, no. 1, spring 2005, pp. 46–52 (↑)
Pages linked to this page
This work by Jim Falk is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License Click on the logo to the left to see the terms on which you can use it.