Nestler 0321 Kanalbau system Kroll channel builder slide rule 1960 Germany

This is a very interesting model aid to the engineer for building channels. It is the model Kanalbau, system Kroll. You can find a copy of the manual here (in German). It has unique scales on the back of the slider as well as formulas and mathematical references on the back of the rule. It is an ca 1960’s model made in Anagit (plastic compound used by Nestler). This model was only produced between 1955 and 1965. There is some wear to the prints (Nestler name and company name on the back) where it was being held by the user. It comes in the original blue Nestler box and with the outer paper box.  Slide rule, sleeve, manual and cursor are in very condition the box is missing the side and shows clear signs of storage. The rule measures 29,5 cm or 11 3/4 inches wide. Check the attached video on how to work your vintage man tool : slide rule operation instructions!