Gamma 2511Try It!

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The 10-inch Rietz rule typ 2511 was in production much less time than others, only manufactured in the Gamma plant. The rule was made of aluminium, the scales in two colors - ordinary scales in black, inverted scale and extensions in red - were painted with white background. The structure is very interesting, has similarities with wooden rules: the upper and lower half of the body were connected by metal sheets. There are more unusual things: the 3-index window made of plastic was framed in 3-direction, and on the frame there is a gamma-sign related to Gamma factory; on the back the rule has two holes make the rear trigonometric scales readable; the slide is trapesoid-like so it can't be inserted inversely. The machines required to produce this type of rule weren't moved to Vác, so the line was closed in 1951.

• Brief history of Gamma slide rules
• Slide rules in Hungary