Faber-Castell 1725


Logo on the back


Length 34 cm
Number of scales 7
Country of origin Germany
Country of manufacturing Germany
Year of manufacturing 1950
Status of the slide rule Normal signs of use
Material of the slide rule Plastic
Type of cursor Clear plastic with metal pointer
Status of the box Normal signs of use
Status of the manual None
Collection number 163
Further comments This is a very unusual slide rule. I have not been able to find the type 1725 in any list, book or website.

According to Dieter von Jezierski, THE expert in the area of Faber-Castell slide rules, it is not a real slide ule but a socalled "Bruchgrenzenmaßstab". A calcualtion device used in the mining industry to compare dates for limits of breaking with various angles of inclination.


 Last updated: 04-09-2009