USD $11
Great for the business person on the go, or anyone concern with turning a profit. Usage instructions printed on reverse side.
Stock: Lots
USD $25
Despite the prevalence of smart phones, some times you need a classic. Produced in 2015, is this universal date finder circular slide chart, with usage instructions printed on the back.
Y2K compliant!
Stock: 3
USD $10
4″ Pocket Date Finder Circular Slide Chart
Stock: Lots
USD $8
A purpose built circular slide chart for selecting lens size based on CCTV sensor size, vertical and horizontal object dimensions, and object distance. Usage instructions included on the reverse side of the calculator.
Stock: 17
USD $8
Usage instructions printed directly on the chart, used for selecting duct sizes based on desired air flow.
Stock: 1
USD $8
Coen Emissions Calculator Slide Chart, used for calculating standardized emission outputs from conventional combustibles (oils, gas, coal, etc).
Stock: 1
USD $8
Metalaire Electric Duct Heater Slide Chart, user instructions printed directly on the slide chart. One side handles wattage magnitude conversion, single and three-phase amperage-to-voltage requirements, and duct area to heat density calculation.
The reverse side calculates airflow, and duct sizing based on diameter / cross-section.
Stock: 1
USD $8
Features conversions for multiple distance units, weight, liquid/dry volumes, temperature, and area.
Stock: 1
USD $12
Boonton Electronics Slide Rule for Reactance / Q / Dissipation Factor, includes operating instructions.
Stock: 1
USD $75
Solid steel body slide rule used for metabolic calculations. Instructions printed on reverse side of rule.
Stock: 1
USD $10
“Puts old heads on young shoulders,” which we can assume does not fix back pain, but instead gives a convenient and ingenious slide chart for calculating angles and sides for triangles.
Stock: 1
USD $8
Easy slide chart for converting length, mass, area, temperature, and volume. Additional reference data and usage instructions on the reverse side.
Stock: 1
USD $35
Convenient an easy to use trigonometric slide charts for solving a variety of volume and area equations.
Stock: 1
USD $55
“Back in my day we had it all memorized!”
The truth is unveiled! They had convenient trig slide charts, complete with instructions!
I’ll be the walk to school wasn’t uphill both ways, either…
Stock: 1
USD $8
One side is used for calculation of resonant frequency problems, and the other for calculating capacitive and inductive reactance.
Stock: 1
USD $10
Continental Equipment Co – Butterfly Valve Sizing Slide Rule CE-V (Very good condition)
Stock: 1
USD $40
Novotni Weight Slide Rule, used for calculating mass based on metal type and volume. General discoloration to body, significant wear around edges. In working condition, and includes original manual.
Stock: 1
USD $8
Profit Calculator 5″ Circular Slide Rule
Stock: 1
USD $10
This convenient pocket rule uses distance, voltage, and current to determine wire/cable gauge. Instructions are printed directly on the front of the rule, and the reverse side contains a reference table of copper wire data.
Stock: 1
USD $10
PS 69 Proportional Scale 5″ Circular Slide Rule, usage instructions printed directly on the front side of the rule.
Stock: 1
USD $15
Williams Decimal & Metric Equivalent Pocket Circular Slide Rule
Stock: 4
USD $15
A useful pocket metric/imperial pocket converter that does weights, volumes, and temperature on one side, and area and length on the reverse side.
Stock: 1
USD $45
This is a very thorough and intuitive conversion set created by Pickett which uses interchangeable discs secured by a thumb screw to modify the rule for different unit conversions. The rule also features C & D scales for multiplication and division.
The original packaging is included, which features detailed and easy to understand operating instructions.
Stock: 1
USD $55
This is a desktop / countertop conversion tool that uses three dials to convert mass and volume, and a scale for temperature. Originally meant for use in the kitchen, but just as good for other purposes.
Stock: 1
USD $49
What’s it do? Not entirely sure, but it is in very good condition with no marking or fading. Features plastic standoff feet for desk operation.
Stock: 1
USD $169
This is a Mark 5 Pilot Balloon Slide Rule manufactured around 1968. It measures 63cm[24.75in] long, 6.3cm[2.5in] wide and 12mm[0.5in] thick. The printed scales are engraved in the plastic faces. The slide rule has 4 captive cursors that ride in slots on the top and bottom edges. Each can be moved independently of one another. Steel knobs at both ends of the slide facilitate movement of the slide. These were made for and used by UK Government agencies, and not individuals. The Met.(meteorological) Office of the United Kingdom designated at least 6 different Pilot Balloon slide rule models. The first model in appearing 1915 made of wood by J.J. Hicks with two slides and introduction of the final, MK 5 model in the Late 1960’s.
Made in England by Blundell Harling Ltd – Weymouth, England.
Stock: 1
USD $24
12″ / 10″ plastic body Slide Rule
LATE MODEL, made by Sterling (later Borden which bought out both Acumath and Sterling Plastics, and continued to sell under those names). Includes instructions, black engraved and filled scales, and yellow contrasting color slide. Can do 16 metric conversions from US standards to Metric units and vice versa. Front slide for distance and area, reversible slide for weight and volume conversions. An inexpensive and practical rule for any science students, cooks, or anyone needing to work in both unit systems. Made in USA. These rules come new, still sealed in their original packaging.
(16 Conversions)
Front – [ Inches/cm, m/feet, m/yards, miles/km, sq. in./sq. cm, sq.m/sq. ft x10, sq. m/sq yards, sq. miles/sq. km ]
Back – [ cu. in./cu cm x10, cu m/cu.ft.x10, cu. m/cu. yards, l/qt., oz./g x10, kg/lbs, metric tons/short tons, gal./l]
Stock: 3
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 $119
Stephenson-Pfahl Hardenability Slide Rule
Stock: 1
USD $85
Fearns W25 Castings and Forging Weight Calculator Circular Rule (new/mint). One with a green case and one with a brown case.
Stock: 2
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 $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 $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 $255
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 $225
This special late production Foxboro flow rule is used to calculate flow parameters and rates for liquids, steam or gas. This is the version custom made for Foxboro by Hemmi of Japan, and has red, blue and black engraved and filled scales.
Pipe schedules are color coded for easy operation. The unusual design uses many dedicated scales sets on both sides, and includes the fitted factory box and manual, and gold embossed leather case, all in MINT condition!. It’s a rule you will really enjoy in your collection, or on the job doing steam or hydraulic pipe fitting.
Stock: 2
USD $25
A double sided slide chart used for frequency calculations. Includes original instruction sheet in German.
Stock: 1
USD $25
This star finder and identifier is more versatile than many others, as it comes with 10 different latitude overlays ensuring this star-finder is useable in many different areas.
Includes manual, 10 latitude overlays, double-sided circular map/chart, and protractor.
Stock: 1
USD $25
Made from two durable acrylic discs with one half having a star map, and the other having the field of view and time of day, this star finder is easy to use and very popular.
Stock: 1
USD $35
Clear and easy to use, this star finder has two concentric rings on one side for lining up the chart to your surroundings, and easy to understand directions on the reverse side.
Stock: 2
USD $150
Don’t be caught in the cockpit without this device! Set comes complete with case, manual, multiple charts, and double sided circular slide rule.
Provides arithmetic and vector solutions for for aircraft speeds of 90 to 2 000 knots, with consideration of errors due to aircraft acceleration. Dead reckoning capability of a plotting board.
Stock: 1
USD $15
If you’re still refusing to use the metric system, and don’t want to do your calculations using fractional lengths of football fields, then this circular slide chart will be very useful. On the inner ring it provides calcualtions in both fractional and decimal quantities.
Stock: 1
USD $35
This ruler uses temperature responsive liquid crystals to read-out room temperature in C/F. It also features metric and imperial measures on the upper and lower edges, and a slide in the center for completing metric/imperial conversions for mass, volume, and distance.
Stock: 1
USD $15
The Sterling “Add-It” machine uses an included stylus to allow a user to add and subtract. Usage directions printed on the front of the device.
Stock: 1
Sphere Research Corporation