Hemmi Slide Rule Catalogue Raisonné
Part II

Rules Without Known Model Numbers

Donations are
tax deductable

The Hemmi Catalogue Raisonne (both parts I and II) by Paul Ross of the SRTCo.us is being preserved at ISRM.

This part of the Hemmi Catalogue Raisonné lists Hemmi-made model number. These rules were given names ("Calorie," Real Estate") instead of model numbers or were made for other companies (SKF, Carrier, Foxboro) or made for the military. There are also some rules which probably were assigned Hemmi model numbers but it is unknown whatthat model numberwas--e.g., the 1938 "Astronavigation" rule

As of March 2015, The Hemmi Slide Rule Company Ltd was still in business in Tokyo. They are engaged in development and manufacturing of printed circuit boards, fluid control devices, semiconductor manufacturing equipment and several minor businesses -- one of which is the design and manufacture of custom slide rules of the style called a "slide chart." Hemmi has not manufactured logarithmic slide rules since about 1975. They have an English-language web site at https://www.hemmi-inc.co.jp/english/ .

Descriptions here are arranged by type of construction.

Paul Ross thanks D. Boone, Bill Lise, Atsushi Tomozawa, Hitoshi Nori and Wataru Tsuchihira for the help they have given.

Return to Part I of the Hemmi Catalogue Raisonné

Bamboo and Celluloid Closed-Body Rules

SKF Bearing Rule, 1930s

Designed and distributed by SKF.Implements various calculations related to bearings. Table on back explains scales and formulas ( Picture is modified from Herman van Herwijnen's Catalog.)

"System Haraguchi" Slide Rule for Weight/Volume Calculations of Metals. 1930s

Note unique "slide-within-a-slide" construction.

Designed by Susumu Haraguchi. The design first appeared in a 1925book by the inventor. I can't find any indication of a Hemmi model number for this rule but it was listed as item number 4496 in the 1932 Tamaya catalog. It was also shown (without a model number) in a 1930s Hemmi Japanese language general instruction manual. In those sources the rule was shown with an earlier "frameless" cursor. (The same illustration was used in both sources.)

Photo, and most of this information, from Hitoshi Nori. Nori estimates the dates of availability as 1930s to WWII.

Matsuda Tube Waterways Rule, 1930s - 1970s

Implements "Hazen & Williams formula" for calculating pressure loss due to friction in pipes. The picture shows a rule belonging to Wataru Tsuchihira. Its date code is "UE" (May 1970).

All-Plastic Tube Waterways Rule (1970s?)

Same scales as bamboo rule above but all-plastic closed-body using same cursor as Hemmi P280, P281, P283. No date code. Photo courtesyWataru Tsuchihira. (Click on picture to enlargeit.)

Ooiso Calorie Rule, 1930s

Click on picture to enlarge it.

There is an article about this rule dated 1939 (by Mr.Toshio Ooiso). I think this is a Calorie Slide Rule referred in "Development History of the SlideRule" by JisukeMiyazaki. Thereare instructions on conversion table on back (in Japanese).

This rule is quite rare; I am indebted to Wataru Tsuchihira for the picture and information.

Ratio Rule, 1938

The only known example of this rule is owned by Keiji Nakamura. The photograph is from his blog at https://knak69.blogspot.com/2023/03/hemmi-fishprice-and-ratio-rules.html. Construction is celluloid on bamboo. The rule is designed to calculate three ratios: Body Weight/ Height,Chest Circumference / Height,and Sitting Height / Height.

Conversion Slide Rule, Pre WWII

250 x 34 mm. The pictures are from a Japanese auction which ended February 5, 2008. Here is Atsushi Tomozawa's explanation ofthe scales: "The scales are captioned (from top to bottom) Year(G), Month(E), Month (F), Reverse(CI), Day(C), Day(D). The gaugemarkson M scale are various units of length and area, some Japanese and some European.It appearsthat this rule is designed especially for unit conversion." I can find no Hemmi documentation of this rule.

Artillery Rule, 1942

Jihei Miyazaki [Development History ofthe Slide Rule, May 1956] and Katsunori Kadokura [Chronology of Japanese Slide Rules, Journal of the Oughtred Society, vol.1, no. 2, August 1992.] both list an "Artillery" rule as being introduced in 1942. The rule pictured here belongs to D. Boone. It came in a box marked "Artillery" and "Science School #215;" its identification as the Artillery Rule of 1942 is tentative but the style of writing on the box definitely dates it before 1945..Scales on the pictured rule are: Upper slanted edge: Two linear scales 0-10 and 600-0. Face: L1, DF [ CF, L2-L1, CI, C]D, A. Bottom edge:0-20cm. Body rear: 0-200 linear and 5 - infinity reciprocal. Slide rear: T1, T2, S2, S1. Trig functions seem to use a system wherein 1600 units equal 90 degrees.

See also LOGA 6400 below.

Nishiki, 1942

Top, slanted edge carries a 0-50 cm scale. All four scales on face of rule are identically divided linear scales (0.4 mmper unit) which means the rule is for addition and subtraction--not multiplication and division. Scale on upper stator is 200-0-200, 160mm long in center of rule. Upper scale on slide is 0-500, 200 mm long at left end of slide. Lower scale on slide is linear 100-1350 offset by 50 units from upper scale on slide. (Total length 500 mm) Scale on lower stator is same as scale on upper stator except placed at right end of rule. Hairline on left cursor extends over upper two scales only; hairline on right cursor extends over lower two scales only. Face width 34 mm.

Triangulation Rule, ca 1940

This 50-cm rule has only one magnifying cursor; the picture shows two cursors because it is stitched together from two scans. Function of rule is unknown; "triangulation" is just a guess. I suspect it may be the Altitude Correction/Height Adjustment Rule above but my friend Atsushi Tomozawa suspects it was used by airplane navigators or for aerial surveying. Front scales are e [L, N1/3, N1/2, T,N]X and a partial-length unlabeled scale belowthe X scale. The e, N, and X scales are three-cycle logarithmic: e runs from 10cm to100m, N and X runfrom 1 to 1000. The N1/3 and N1/2 scales are the cube and square rootsof the N (and X) scale. The N (X) scale gives the tangentofangles which are engraved onthe right end of the N1/2 scaleand the full length of the T scale. The range of angles is6o to 89o57'. (Compare tousualrange of6o to45o.) The unlabeled scale on the bottomof the rule ismarked 1' to 17'; each graduation is 1/60 of the graduation on the X scale.

There are three scales on the back of the slide: S ranges from 500m to20km; log S ranges from 2.7 to 4.3; a ranges from 3' to 90o.

There are several tables of formulas on the back. The following isa paraphrase ofTomozawa'a explanation ofthose tables: One is definitely related to distance (height) estimation using triangulation. The secondtable consistsoftriangle formulas. The third tablecontains three items: (1)Indirect method oflevel estimation; (2) Levelmeasurement bybarometer; (3) Earth parameters. The fourthand fifth tables are related to map reading. The sixth setof formulas is titled"Westward inclination ofearthmagnetic field." Seventh: (1) Formulas for photographic surveying; (2) Angleconversion factors. Eighth table contains various constants such as 1 mile = 1,609 meter.

Picture provided by D. Boone.

"Byoutou," 1944

//Closed body||. 250 x 34 x 11 mm. (Same body asHemmi 50W.) Calculating scales onfour surfaces (front, back of slide, top slanted edge,and bottom vertical edge). Top, slantededge carries a non-linear scale labeled "V" near left end and a 0 - 10 cmscale at right end. Face of rule carries eightfull-length non-linear scales labeled simply (1) - (8). Bottom edge of rule carries non-linear scales (9) and (10). Labels (11), (12) and (13) appear at the right ends of scales (2), (3) and (6). Labels (14) and (15) appear at the right endsof scales (6) and (5)but upside down--as if the user were to reverse the rule when using them.Non-linear scales (16), (17) and (18)areon the back of the slide.Special cursor with flexible tabextending from top edge; cursor must be reversed when usingscales onbottomedge of rule. It is possible that some operations were tobe performed with the rule upside down, with the slanted edge toward the bottom. There is a plastic table on the back with settings for the C and D scales and trigonometry formulas; none of whichseems to relateto this slide rule.

The following information is from Atsushi Tomozawa: The name "Byou-tou" comes from two Chinese characters "byou" and "tou" ona box containing a specimen of this rule in the Hemmi Offices in Tokyo. Thefirst character translates to sprout, bud or shoot ofa young plant; the second means "head." "Shooting Heading"is not animpossible translation. "Development History of the SlideRule" by Jihei Miyazaki states that the Byoutou rulewas introduced in 1944 but does not mention what function the rule served. Another book, "Historyof the Slide Rule," written for the Royal Navy Military Schools in 1944explains how to use the rule to calculate a correctionangle for firing at moving ships; thecorrected angleis called "corrected byoutou."

It is possible that this rule is an improved version of the Artillery Rule of 1942, above.

These rules are relatively common but cursor is usually missing.

6400 Ao/oo Topo (Swiss Army Artillery Rule) 1952

This slide rule is mentioned in conjunction withthewell-knownLOGA TOPO 6400 Ao/oo circular stadia rule in a Swissarmy publication"Instruments for Measuring and Observation in the Artillery"published 1952. The label on the slide reads "6400 Ao/ooTopo" which impliesthat the rule was intended for use in conjunction with the Loga rule. Thepicturedspecimen is in the Swiss Army Museum. (Information from Jacques Perregaux, photo courtesy of Stiftung HAM, Thun, Switzerland, www.stiftung-ham.ch.)

CJ-805-3B Engine Performance, 1967

GE jet engine CJ-805 powered the Convair 880 and Convair 990 airliners. The pictured rule belongs to D.Boone; datecode is "RD."

Meteorological Slide Rule?

eBayauction 6248834536, Feb-05-06. Wonby "Waynesworld." Here is theseller's description:
"A 10 inchbamboo baseSunHemmi rule, no model number, andnot listed in the catalogs available. The face scales are:Pressure in mmHg, B, CI, Height(same as C scale) ABS Temp (-50 to +200C). The reverse side scales are:Height in Km, Pot. Temp. Coef. (mmHg.mb), and Temp. Fact. (-60to +40 C). Therule has a 10 inch scale onthe lower edge and a 0-27cm scale on the upper edge. Possibly used for barometric calculations and othermeteorological purposes."

Carrier Ductuler (Bamboo), 1961.

Bamboo and celluloid. Fordesign of airconditioning ducts. Date code"LC"= March1961. Predecessortothe all-plasticCarrier Ductuler.(See section on all-plastic rules below.)

Unknown Materials

This section lists rules mentioned in various non-Hemmi sources. They may not actually exist. The original source may bein error or I may have misunderstood what was being described orHemmi mayhave changed their minds before actuallyproducing them. If they existed they wereprobably closed-body rulesmade of bamboo and celluloid similar to the devices listed above.

Astronavigation Rule, 1938

Jihei Miyazaki [Development History of the Slide Rule, May1956] and Katsunori Kadokura [Chronology of Japanese Slide Rules, Journalofthe Oughtred Society, vol. 1, no 2, August 1992.] both list an "Astronavigation" rule as being introduced in in 1938.

Ratio/Percentage Rule, 1939

Jihei Miyazaki [Development History of the Slide Rule, May1956] lists a "Ratio" rule as having been introduced in 1939. Katsunori Kadokura [Chronology of Japanese Slide Rules, Journal ofthe Oughtred Society, vol. 1, no 2, August 1992.] translates the same item as "Percentage" rule.

Air Navigation Rule, 1939

Jihei Miyazaki [Development History of the Slide Rule, May1956] and Katsunori Kadokura [Chronology of Japanese Slide Rules, Journalofthe Oughtred Society, vol. 1, no. 2, August 1992.]list an "Air navigation"or "Navigation" rule as being introduced in in 1939. Both list it in addition to the 1938 Astronavigation rule, above.

Communications Engineering Rule, 1939

Hideaki Hirano, in his book titled "History of the Slide ruleDevelopment,” gives the date for this rule as1939. JiheiMiyazaki [Development History of the Slide Rule, May 1956]and Katsunori Kadokura[Chronology of Japanese Slide Rules, Journal of the Oughtred Society, vol.1, no. 2, August1992.] both list a "Communications Engineering" rule as being introduced in 1943.It is not impossible that rule shown asHemmi model 120 MIGHT in the Hemmi Catalogue Raisonne, Part I, is, in fact,this Communications Engineering Rule.

Merchant's Slide Rule

400 mm x _. The only information I have on this rule is the name from Bill Lise.

Altitude Correction/Height Adjustment Rule, 1943

Jihei Miyazaki [Development History of the Slide Rule, May1956] lists an "Altitude Correction" rule as having been introduced in1943. Katsunori Kadokura [Chronology of Japanese Slide Rules,Journal of the Oughtred Society, vol. 1, no. 2, August 1992.] translates the same item as "Height Adjustment."

Transmission Rule, 1943

Jihei Miyazaki [Development History of the Slide Rule,May 1956] and Katsunori Kadokura [Chronologyof Japanese Slide Rules, Journal of the Oughtred Society, vol. 1, no.2, August 1992.] both list a "Transmission" ruleas being introducedin in1943.

Power Load Rule, 1955

Jihei Miyazaki [Development History of the Slide Rule,May 1956] says a "Power Load Rule" was developed in 1955 for KyushuElectric Co

All-Plastic Closed Body

YS-11M-A Aircraft Load Adjusting Rule 1964-74

||Closed body|| All-plastic. English language. Load adjuster for NAMC (Nihon Aircraft Manufacturing Co.) YS-11 twin-engine turboprop. Plane was manufactured from 1964 to 1974;rulepresumably dates from that period. Picture copyright by Bill Lise.

Real Estate, 1964

All-plastic ||closed body|| in twosizes: 200 x 28 x 5 mm and 120 x 25 x 3 mm. Front scales: To,m2 [Ken, m] m, Ken. Rear scales: Blank. Japanese language. Known date codesOJ, OK. Instructions printed 1965.

Carrier Ductuler (All-Plastic), 1965

All-plastic ||closed body|| 200 x 28 x 5 mm. For design ofair conditioning ducts. Probably predecessor toHemmimodel P141. Date code of rule shown is "PC" = March 1965.

There was an earlier bamboo version of this rule. See the "Carrier Ductuler (Bamboo)" in the "Bamboo and Celluloid Rules" section of this Catalogue II.

Yazaki Aroquicker, 1967

Yazaki Corporation is a diversified manufacturer of gas, air conditioning and solar equipment. I don't have any idea what this slide rule calculates.Date code "RH" = August 1967. Photo supplied byWartaru Tsuchihira.

Electrician's Rule, ca 1965

12.5-cm all-plastic closed body. Scales seem tobeoriented toward selection ofwire gaugeand calculation of voltagedrop and power loss. Rear of slidecarries three scales. Possiblysame as Power Load Rule (1955) described above.
Picture courtesy D. Boone; therulecarries nodate code.

Accumulator Slide Rule

An accumulator seems to be a device for "storing" hydraulic pressure. Manual is in English and Japanese. Pictures and information courtesy D. Boone.

Hydraulic Rule, 1967-1975

There are at least two versions of this slide rule. The earlier version is celluloid on bamboo. The specimen shown here isdated "RH"(August 1967).

The later version is all-plastic. The specimen shown here is dated "ZC" (March 1975).

Click on picture to enlarge.

Scale length for both of these rules is 180 mm.
There arethree logarithmic scales which runfrom0.1 to 10,000 (five cycles).

Allinformation from Wataru Tuschihira whoownsthe specimenspictured.

Hydraulic Flow Rule 1971

Another hydraulic flowrulefromHemmi. This specimen is dated"VG" (July1971).Front ofrule (upper picture) implements theHazenand Williams formula; rear (lower picture) implements the Manning System.The specimen pictured belongs to Wataru Tsuchihira.

Dr Won's Hydraulic Slide Rule

Click on picture to enlarge it.
A similar slide rule was sold on eBay January 15, 2017 by "daboyryan" for $213.50. The only information provided bythe seller was "This slide was invented byProf. DrTae-Sang Won and is made for Pipe Lines." I have notbeen able to getany information on Korean patent 1743 or Japanese patent 165131.

Yokohama Kogyo Sekkei / Hemmi Flow Rules, 1972-73

Click on picture to enlarge it.

There are two versions of this slide rule. The scales on the longer rule have an unusual length of 278 mm (10.9 in) whereas the scales on the shorter rule are the common 125mm (4.9 in). Both specimens shown here are owned by Wataru Tsuchihira whokindlyprovided the picture. The previous owner toldhimthat the shorterrule was a promotional give-away from a company which designs wastewater system. The shorter rule has manufacturing date code "WK" (November1972); the longer "XD" (April 1973).

Body Weight Balance, 1972

200 x 28 mm (same blank as Hemmi P45D, P45K, P45S). Listed ina 1972 Japanese language flyer. Calculates "obesity" (similar to body mass index, BMI?),"Raurel Index," and "Carp Index" based onstudent's weight and height. Brochure specifically usesthe word "student."

Diver's Decompression Slide Rule, 2004

||Closed body|| 200 x 32 x 4.3 mm. All-plastic.(Same blank as Hemmi P135k.) Custom manufactured by Hemmi ca 2004. The pictured specimen was given to a group of Japanese slide rule collectors as an example of Hemmi's recent production; it is presently in the possession of Mr. Nori. Two of the phrases in red translate to "Body gas pressure" and "Dive depth;" I think it calculates decompression times for divers.

Lung Ventilation Calculator, 2010?

This device was sold on Yahoo Japan in May 2019. Used to calculate lung function. ("Rifadin" is an antibiotic used to treat tuberculosis and other deseases.) Construction is similar to other Hemmi rules known to be manufactured in early 21st century.

Thanks to Cliff Frohlich for bringing this to my attention.

Cardiothoracic Ratio Calculator, 2015?

||Closed body|| 200 x 32 x 4.3 mm. All-plastic. (Same blank as Hemmi P135k and Diver's Decompression Slide Rule above) I think this was a current Hemmi productin 2015. Picture supplied by Wataru Tsuchihira.Inset detail shows one of the springs which hold the slide in place.

Heart/Chest Rule 2018?

Transparent rule at top of picture is used to measure heart andchestdimensions on x-ray. Instruction are in Japanese. Photo and information from Cliff Frohlich.

Gas Calibration Rule

This specimen carries no date code but, judging from construction, it probably dates from the 1970s. Back of slide is blank. Pictures and information courtesy Wataru Tsuchihira.
"OVAL" Pneumatic Flow(?) Rule

This rule was discovered by Joshua Kanazawa. It's exact function is unknown but "OVAL" is a well-known manufacturer of pneumatic devices. Date code "KC" = March 1960.

Devices made of Folded Paper, Plastic Sheeting, etc.

Sawa's Exposure Reckoner A R S, 1936

Paper slide ruleforcalculating photographic exposures. Physical construction almost identical to Hemmi model 46. Instruction Manual dated 1936. "Sawa's Exposure Reckoner A R S" in English on box andcase but pretty much everything else is in Japanese. Photo and information courtesy Wataru Tsuchihira.

IJN 98 (Imperial Japanese Navy Maneuvering Rule, Type 98),1938-43

Handheld device for naval gunnery calculations. Type 98 means "type approved in imperial year 2598" (1938).

Left photo is from a June 2005 auction on Yahoo! Japan; right photo isfrom anAugust 2014 auction on TradeMe (New Zealand). Information is from Bill Lise who examineda museum specimen dated 1943 onits back.

Jitsumu Kyouiku Kenkyujo

An all-paper Hemmi slide rule discovered by Wataru Tsuchihira. Scales are 150 mmlong. Back isblank except for "JitsumuKyouiku Kenkyujo" in Japanese characters. The Hemmi logo in condensed black Arial type was used by Hemmi inthe 1950sand 60s. Jitsumu Kyouiku Kenkyujo isa foundation, still in business in2015, offering various correspondence courses. Areasonable surmise is that this slide rule was supplied to students. (All information from Wataru Tsuchihira.)

Chu 1 Jidai Furuku (1970)

Another all-paper Hemmi slide rulediscoveredby Wataru Tsuchihira. Distributed witha magazine for first-year junior high school students inFebruary 1970. Identical construction to Jitsumu Kyouiku Kenkyujorule above except for cursor and textonback of rule. (All information from Wataru Tsuchihira.)

Baseball, 1966 -

125 x 28 mm. Probably a promotional item from a professional baseball teambut listed inHemmi Catalog 6911 for a price of 120¥ (about $0.33 in 1969). Allfour scales are 1-cycle logarithmic but the upper scaleonthe slide is folded at0.9. Came with a fullsheetof instructions (in Japanese) plus abbreviated instructions on back of rule. Instructions use example data from 1965 baseball season.(Information andrulecourtesy Wataru Tsuchihira.)

Motoyama Valve Slide Rule

Air conditioning and refrigeration.

Miscellaneous Devices

Slide Projector Slide Rule, 1940s

Labeled "SUN HEMMI 'Projection Slide Rule (4)' (for simplex)". Manufactured by"NIHON KOGEI CO., LTD" for use with lantern slide projectors whichwere popular for technical presentation in the 1940s and 50s. Scales are identicalto Hemmi model 2662. Three sheets are superimposed: (1) Scales on face ofrule, (2) Scales on rear of slide,(3) cursor. More modern projection slide rules for overhead projectors use thesame three sheets.

Picture and all information courtesy Hitoshi Nori.

Planisphere (1940s)

Based on Kanji characters usedandhowdomestic Japan is referred toin the instructions on back, WataruTsuchihira thinks this planisphere was designed before end of World War II. He has also found references to it from as late as 1949.

Click on image to enlarge it.

Versor Electronic Calculators, 1976

In1976Hemmi teamed withBrother Industries to produce a a lineof electronic calculators. There were four models:Versor 804,814, 824and 834. (The pictured calculator is marked "Hemmi Versor 824.") This information is from Hitoshi Nori who is not aware ofany specimensin existence in 2009.

MR80 Electronic Calculator

This device is owned by Wataru Tusuchihira whosaysit is working finein June 2017. Manufactured by Brotheras model508AY.

PressMate, Late 1980s?

Calculates bending and shearing forces in machine presses. Back iscovered with tables and formulas. Scales are120 mmlong;body is 46 mmwide and uses same CP-280 cursor as P280, P281 and P283 slide rules. 16-page instruction manual. All Japaneselanguage except name "Pressmate" on box andsome labels like "(shearstrength)"on rule.No date codebuta date in the late 1980scan be inferred since thescales are silkscreen printed with thin transparent overlay like P135k (which was made in2004) and the device was distributed by "MISUMIShoji Co., Ltd." which used thatname only from 1963 to 1989. All information from Hitoshi Nori who also supplied the photograph.

Duplex Slide Rules

Pocket Versalog, ca 1957 - 68

Manufactured by Hemmifor the Frederick Post Co. ofChicago (Post model number 1461) and for the Hughes Owens Co. of Canada (Geotec 341 3050). Samescalesasfull-size Versalog (See Hemmi 258): LL0, LL/0, K,DF [CF,CIF, CI, C]D, R1, R2, L and LL/1, LL/2, LL/3 [TT, SecT ST, Cos S, C] D, LL3, LL2, LL1. 125 x 34 x 3.5 mm.

Onbothfull-size andpocket Versalogs, the COSscale was in navy blue until1960 when the color changed to green. The earlier rulesaregenerally identifiedas models IA, the latter asmodels IB.

Replaced by Pocket Versalog II (same model numbers) in November 1968.

Versatrig 1960 -

Manufactured by Hemmi as a cheaper version of the Post Versalog Slide Rule. Post Catalog Number 1450 until ca1972 after which it became Teledyne-Post 44CA-500. Soldin Canada as Geotec 341 3120. Available from about 1960 (Instructions copyright 1961) but did not appear in Post Catalogs until 1969. Scales K, DF [CF, CIF, CI,C] D, R1, R2 and L, A [TT,SecT ST, Cos S, C] D, DI. 250 mm x 1-5/8x 1/4 inch.

Pocket Electronics Rule

125 x 38 x 3 mm all-plastic closed body. The pictured rule carries no date code.

SMC Pneumatics Slide Rule, ca 1965-67

Plastic duplex. 250 x 46 x 5 mm, same blank as Hemmi P261, P262 which were made ca1965-67.

Foxboro Flow and Valve Rule, 1967

Plastic duplex. 250 x 46 x 5 mm. No date code but instructions are copyright 1967. No mention of Hemmi except"Hemmi Japan" embossed into cursor. There are two versions of this rule: "English Units" (upper picture) and "Metric Units" (lower picture.)

Yokogawa/Foxboro Flow and Valve Rule, 1967

Identical to Foxboro Flow and Valve Rule (metric version) except "@SUN@ HEMMI JAPAN" and "YEW" (Yokogawa Electric Works) in box added to left end of rule. Date code "RJ" (October 1967) on rule and "6809"(September 1968) on rear cover of Instruction book.

This specimen and it's instruction book belong to Wataru Tsuchihira.

Metal-Chemistry Rule I, 1967

Duplex, 500 mm x 1-3/4 x 1/4 in. Front scales: L,K,A,DF[CF, CIF, CI, C] DoK, LL3,LL2,LL1 Folded atp. Rearscales: Ch A~M, Ch N~Z, M1, Xw [X, M2, ToF, ToC, ToK] Patm, PmmHg, Tow, G.

This rule belongs to D. Boone; it is the only specimen ofthis variant known tome. It carries a datecode of "RA." See discussion of Metal-Chemistry Rule II below foradditional information.

Metal-Chemistry Rule II, 1968-

Duplex, 500 mm x 1-3/4 x 1/4 in. Front scales: L,K,A,DF[CF, CIF, CI,C] DoK, LL3,LL2,LL1 Folded atp. Rear scales: Ch A~M, Ch N~Z, M1, Xw [X, M2, TI, SI, G] Patm, PmmHg,ToF, ToC.

Two specimens of this rule are known; neither has a date code. Atsushi Tomozawa purchased the rule pictured here along with a Japanese language instructionmanual directly from Hemmi about 2004. The Hemmi employees he dealt with identified it as a "Metal-Chemistry" rule. (D. Boone owns the other specimen.) Basedupon its similarity to the Hemmi Chemistry rule (model 257L) it is possible that this rule was intended to be marketed as mode l277 but no such model number appears in anyknown Hemmi documentation.

Versalog II, 1968 -

The original Versalog was the same as Hemmi model 258 and is described under that model number on the main page of this Catalogue Raisonne. The Versalog II, introduced in November 1968, re-arranged the original Versalog scales and added an "A" scale. Scales:LL/0, K, A,DF[CF, CIF,CI, C] D, R1, R2, LL0and L, LL/1, LL/2, LL/3 [T T, SecT SRT, Cos S, C]D, LL3, LL2, LL1.250 mm x 1-3/4 x 1/4 inch. Sold in the United States by the Frederick Post Co. as model 1460 (Same number as original Versalog) until ca 1972 when it became Teledyne-Post model 44CA-600. Sold in Canada bytheHughes Owens Co as Geotec model 341-3012. Versalog IIs can be easily distinguished from original Versalogs by the presence of the "A" scale.

Pocket Versalog II, 1968-

Same scales as full-size Versalog II. 125 x 34 x 3.5 mm. Sold in the United States as Post model number 1461 until ca. 1972 when it became Teledyne-Post 44DA-610. Sold in Canada as Geotec model 341-3052.

Pocket Versatrig, 1969-71

Manufactured by Hemmi for the Frederick Post Co. of Chicago (Post catalog number 1451) and the Hughes Owens Co of Canada (Geotec Model 3413125). Scales K,DF [CF, CIF, CI,C] D, R1,R2 and L, A [T T, SecT ST, Cos S, C] D, DI (same as Versatrig). 125 x 34 x 3.5mm.

Appeared in only one Post Catalog (1971). All known Post specimens carry date code "SF"(June 1968) but the only Geotec specimen I'm aware ofhas datecode "TE" (May 1969).

Geotec 341-3670 All-Plastic Pocket Versalog II (c 1975)

Geotec 341-3670. All-plastic version of Pocket Versalog II probably made by Uchida Yoko Company expressely for Geotec. Definitely not made by Hemmi. The question is "Why does it carry the 'Hemmi' name if it was made by Uchida for Geotec?" Standard Versalog II scales: LL/o, K, A, DF [CF, CIF, CI, C] D, R1, R2, LLo and L, LL/1,LL/2, LL/3 [T T, SecTSRT, Cos S, C] D, LL3, LL2, LL1. Picture courtesy Ron Knapp.

Geotec 341-3690 All-Plastic Full-Size Versalog II (c 1975)

Hughes-Owens/Geotec sold the Hemmi 258/Post 1460 Versalog as Geotec model 341-3010 Versalog. The improved Versalog II was sold as Geotec model 341-3012. I can find no record of Geotec model 341-3690 except the specimen shown here which was offered for sale on eBay 1/5/2015 by "baja_ron" (Ron Knapp) with a minimum bid of $2999.99. Ron offered it again on 11/17/2018 and it sold for $435. The picture here is copied from that listing.

Rule is marked "VERSALOG 341-3690" and "HEMMI JAPAN" but I believe it was made by Uchida after Hemmi got out ofthe slide rule business ca1975. Scales are identical to Post/Geotec Versalog II(except COS scale is black, not green) but the all-plastic body and cursor appear identicalto Uchida rules of the same size.

Specimen did not have a case.

Machine Tool Endurance Estimation Rule, 1967-68 (Homma Metal Works)

12.5-cm duplex--same body as Hemmi 149A except solid plastic. Calculation of useful lifetime of bits used in metal turning lathes. Thisspecimencarries date code "RI" (August 1967). The six Japanese characters on the rear upper right say "Designed by Mechanical Testing Laboratory." (Atsushi Tomozawa informs me that the Mechanical Testing Laboratory is now known as "National Institute ofAdvanced Industrial Science and Technology."

Thirty-page instruction manual, "How to Use the Machine Tools Endurance Estimating Rule,"is all in Japanese. Instruction manual is dated 1968.

This specimen is marked "Homma Metal Works" (In English) on the rear lower left. It has a brown leather case embosed with Homma trademark and ten Japanese characters on front plus Homma trademark and "HOMMAMETALWORKS CO., LTD." on back.

There is also a Hemmi-made Homma Metal Works slide chart from about 1976. See the section on Slide Charts below.

Calorie, 1972

Plastic duplex. 250 x 46 x 5 mm. Described in same 1972 Japanese-language Hemmi brochure asthe Body Weight Balance rule, above. This picture is from Kim's Japanese website, http://www.tok2.com/home/kim/sliderule/Calorie.html (which, unfortunately, seems no longer available). Calculates basal metabolism and required calorie intake from height and weight. "Calorie" is printed in English on face but the rule may not have been available with English instructions.

Sash Design Rule 1974

Same blank as Hemmi models P261, P262, P267. The pictured specimen carries date code "YA" (January1974).It belongs to Wataru Tsuchihira.

Denkishoin Electrical Slide Rule, ca 1976

Plastic duplex. 250 x 46 x 5 mm, same blank asHemmi P261, P262. Rear scales are Tq2, Tq1, Sq, R1 [R2, B, CI, C] D, SR, TR1, TR2. This rule was advertised for sale in at least two 1976 issues of "Denki-Keisan," a magazine published by Denkishoin--a publisher of electrical books and manuals. (Information from Hitoshi Nori.) This specimen, which carries no date code, belongs to Atsushi Tomozawa who provided the picture.

All-Plastic Geotec 341-3690 Versalog II (After 1975?)

Hughes-Owens/Geotec sold the Hemmi 258/Post 1460 Versalog as Geotec model 341-3010 Versalog. The improved Versalog II was sold as Geotec model 341-3012.I can find no record of Geotec model 341-3690 except the specimen shown here which was offered for sale on eBay 1/5/2015 by "baja_ron" (Ron Knapp) with a minimum bid of $2999.99. Ron offered it again on 11/17/2018 with a minimum bid of $399.99. The picture here copied from that listing.

Rule is marked "VERSALOG 341-3690" and "HEMMI JAPAN" but I believe it was made by Uchida after Hemmi got out of the slide rule business ca1975. Scales are identical to Post/Geotec Versalog II(except COS scale is black, not green) but the all-plastic body and cursor appear identical to Uchida rules of the same size.

Specimen did not have a case.

Slide Charts

Homma Metal Machining Slide Chart (1976)

Slide chart for determing time required for metal planing turning and drilling. Twelve-page manual in Japanese and English. Manual is dated 1976.

Construction is typical of Hemmi slide charts but probably not in current (2018) production. (Hemmi website does not mention metal machining among subjects for which Hemmi has slide charts available.) Photos and Instruction Manual from Cliff Frohlich.

Homma also distributed a Hemmi-made duplex slide rule designed by the Mechanical Testing Laboratory. See the section on Duplex Slide Rules above.

Duct Slide Chart

Current production as of March 2015. Hemmi website description: "Ductwork and fluid design calculation (air-conditioning system design, duct diameter, etc.)." Photo courtesy Wataru Tsuchihira.

Weight Control Calculator (Current production in 2015)

Instructions (in Japanese) on back. Picture and information courtesy Wataru Tsuchihira.
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