Slide rules HOME page COLLECTION 5" RULES
Make Un-named, Germany (Promotional slide rule for Specialloid pistons)
Model Rietz

1. Although there is no indication of maker on the rule it is a Faber Castell.
2. The rule has a scale of centimetres in the well. Using this tells you the distance from the left hand end of the stock to the right hand end on the slide.
3. Comparing this with the Nestler 0123 shows the difference in interpretation of the word "Rietz". The Nestler has K, CI and L scales in addition to the ones on this rule.
4. Rear of slide rule has marks on stock to allow use of trigonometrical functions without need to remove slider.
5. Table of conversions on rear

Front view
0504-specialloid-01.jpg (14976 bytes)
Detail - front left
0504-specialloid-02.jpg (11548 bytes)
Detail - scale in well
0504-specialloid-03.jpg (25663 bytes)
Detail - back right
0504-specialloid-04.jpg (22404 bytes)
Manufacturing date c 1950
Length 5"
Material Plastic on laminated mahogany
Scales K,A [B,C/ S,ST,T]: D,L
Gauge points p: 3.14: A,B,C,D
r' : 3438 : C,D
r" : 206255 : C,D
c : 1.13: C,D
c': 3.57: C,D
r11 : 6.37: C,D
Cursor Plastic with complete metal frame
Hair lines None
Documentation None
Condition Complete in cardboard box.