USD $159
M.H. Mear Gas Flow Calculator Circular Rule (new/mint)
Stock: 1
USD $59
Coast Navigation Simex Course Converter (new/mint)
Stock: 1
USD $85
Fearns W25 Castings and Forging Weight Calculator Circular Rule (new/mint)
Stock: 1
USD $85
Fearns-Mear Machining Time Calculator Circular Rule (new/mint)
Stock: 2
USD $159
M.H. Mears Pipe Flow Calculator for Liquids & Gases (new/mint)
Stock: 1
USD $135
Concise No. 380 Radio Converter Circular Rule (new/mint), includes case and instruction manual.
Stock: 2
USD $85
Earns W28 Steelwork Weight Calculator Circular Slide Rule
Stock: 1
USD $59
Do you need to measure fallout radiation from a nuclear detonation? This is what you need to do that! I’m sure there are other ways, but this way will absolutely not fail you (doesn’t need batteries), so long as you are sufficiently far away to safely be able to operate the rule.
Stock: 3
USD $125
4 1/2″ Binary Pocket Circular Rule (in green)
(21 Scales !)
Front: – C, CI, A, K, L, Log Log (1.0015-1,000,000), fractions, fractions, drill/thread, mm
Back: degrees, sines, tans, degrees, sines, tans, degrees, sines, tans, Fractional Conversions
Stock: 1
USD $125
5.5″ Circular Aviation Slide Rule
Constructed with one rotating film disk, and rotating cursor on each side. A very sophisticated and beautiful flight computer for doing altitude, pressure, wind drift, time, temperature, and fuel problems.
The rule gives simultaneous solutions in both metric and US/Imperial units, without being cluttered or hard to interpret, an outstanding mechanical and artistic design. Still in demand today among many pilots, but very hard to find.
Made of ‘Aristopal’, comes complete with zippered leather pouch. We have had many requests for this rule from all over the world, this set is in very good condtion, except for a few case scuffs.
Stock: 1
USD $275
5.5″ Circular Aviation Slide Rule
Constructed with one rotating film disk, and rotating cursor on each side. A very sophisticated and beautiful flight computer for doing altitude, pressure, wind drift, time, temperature, and fuel problems.
The rule gives simultaneous solutions in both metric and US/Imperial units, without being cluttered or hard to interpret, an outstanding mechanical and artistic design. Still in demand today among many pilots, but very hard to find.
Made of ‘Aristopal’, comes complete with zippered leather pouch. We have had many requests for this rule from all over the world, this are the first 618’s we have ever had available for sale, all in excellent condition. The similar 617 has an additional rotating wind arrow on the back face, not present on these models. The earlier 616 does not have the red reciprocal degrees printed on the rear compass rose, or the wind arrow.
(22 scales on front, Wind scales on rear)
Stock: 1
USD $95
Fearns A8 Metric Weight Converter, includes case and manual, one side converts imperial to metric, and the other metric to imperial.
Stock: 1
USD $165
5.5″ Circular Aviation Slide Rule
Constructed with one rotating film disk, and rotating cursor on each side. A very sophisticated and beautiful flight computer for doing altitude, pressure, time, temperature, and fuel problems.
The rule give simultaneous solutions in both metric and US/Imperial units, without being cluttered or hard to interpret, an outstanding mechanical and artistic design. Still in demand today among many pilots, but very hard to find.
Made of ‘Aristopal’, comes complete with zippered leather pouch.
Stock: 1
USD $125
4 1/2″ Binary Pocket Circular Rule
(21 Scales !)
Front: – C, CI, A, K, L, Log Log (1.0015-1,000,000), fractions, fractions, drill/thread, mm
Back: degrees, sines, tans, degrees, sines, tans, degrees, sines, tans, Fractional Conversions
Stock: 1
USD $69
Concise Type E Pocket Circular Slide Rule w/Conversion Tables, includes original manual.
Scales: D, C, CI, A, K
Stock: 1
USD $165
nPK-69 Russian Dual Circular Slide Rule w/Chart – RARE.
Stock: 1
USD $179
Originally made by Gilson but sold under a number of different marques (e.g. Post, Dietzgen, Tavella, etc), this 21 scale rule is recognized for its high visibility alternating yellow and white rings.
The rule has unique fractional ‘binary’ scales that permit operations directly with fractional numbers, and also drill size scales. Rotating dual cursors with a slip clutch on one side, and a single cursor on the other.
This specific rule and its case are in above average condition.
Scales include:
Front – C, CI, A, K, L, Log Log (1.0015-1,000,000), fractions, fractions, drill/thread, mm
Back – degrees, sines, tans, degrees, sines, tans, degrees, sines, tans, Fractional Conversions
Stock: 1
USD $149
Originally made by Gilson but sold under a number of different marques (e.g. Post, Dietzgen, Tavella, etc), this 21 scale rule is recognized for its high visibility alternating yellow and white rings.
The rule has unique fractional ‘binary’ scales that permit operations directly with fractional numbers, and also drill size scales. Rotating dual cursors with a slip clutch on one side, and a single cursor on the other.
This rule is in good condition, and the case is in acceptable condition with some fraying and marking.
Scales include:
Front – C, CI, A, K, L, Log Log (1.0015-1,000,000), fractions, fractions, drill/thread, mm
Back – degrees, sines, tans, degrees, sines, tans, degrees, sines, tans, Fractional Conversions
Stock: 2
USD $215
This is a single sided circular slide rule operated by using the two knobs on the top of the rule’s all metal casing. Some details on using these style of calculators can be found here. The Long Scale version of this calculator is specifically designed for use by engineers, draughtsman, and science students.
The designation of “long scale” (also some times called “magnum”) refers to this calculator being 1.5″ larger than the standard Fowlers Calculator, allowing for much finer gradation on the scales, and allowing calculations of four or five significant digits.
Stock: 1
USD $249
This is a very rare 4″ pocket circular rule, that comes with both the original factory box and manual in very good condition.
Scales include: A, C, CI, Log, Log-Log, Binary, S,
Stock: 1
Sphere Research Corporation