IWA 1312 Forrester timber tree cutting slide rule 1960 Germany

This is a later model Forster slide rule, that takes the Nestler timber trader slide rule to a whole new level. Besides providing insights into the amount of wood a tree would yield it also calculates for different types of timber with different grain and a bigger amount of branches, etc. For this it uses not one but 2 slides and a cursor. This IWA 1312 was an important tool to the Forster in the 1960-1980’s and is only seldom seen. It is in good overal condition with some signs of normal use. It comes in an oversized sleeve that is probably not the original (priced accordingly). The rule measures ca 25 cm or 10 inches wide. Check the attached video on how to work your vintage man tool : slide rule operation instructions!