Slide rules HOME page COLLECTION < SITE MAP >
Circular rules
The advantage of these rules was that they could provide long scale lengths, and hence increased
accuracy, in a small space. Their disadvantage was that it was difficult to fit in a full range of scales.
Maker Model Notes Origin
Circulator None given Made by a little known British manufacturer gb.gif (1306 bytes)
Fearns Circular slide rule Has an interesting spiral log log scale gb.gif (1306 bytes)
Concise 28N Carries "Time Life books" logo Original instructions. jp.gif (938 bytes)
Concise 4028 Another promotional rule from Concise jp.gif (938 bytes)
Concise CTCS-552 Carries "Shell" logo. jp.gif (938 bytes)
Concise 300B A duplex circular rule jp.gif (938 bytes)
Gilson Midget A rule with some good ideas and some strange scales Instruction for drill and thread scales. us.gif (950 bytes)
Gilson Binary A larger version of the above us.gif (950 bytes)
Aristo Nr 622 A fairly basic rule. de.gif (910 bytes)
Graphoplex Roplex Scales are turned by knurled knobs. Original instructions (in French). fr.gif (941 bytes)
Eckell Dial-O-Matic Very full selection of scales  
ALRO 200R Box doubles as desk stand for rule  
Fearns Trigonometrical Sepcially for trigonometrical calculations Original instructions gb.gif (1306 bytes)

Original instructions: scanned version of maker's original instructions
Full instructions: complete instructions based on book or similar.
Instructions: instructions based on my own research.
For some rules instructions are given for special scales only.