A Simplon Bilateral slide rule made by Dargue Bros of Halifax (1934 patent). It dates from the mid-twentieth century. This model was introduced in 1935 when it sold for 7/6. It is a ten inch duplex (double sided) rule made of plastic faced mahogany. Unusually, their are two cursor grooves along each edge of the rule and the cursor has to be removed and put on the other side to use the scales on the reverse. Scales are: LU,A{B,C1,C}D,LL//A,S,L,T,D. Maroon card case.
A Simplon Primary Log Log ten inch slide rule. This is the Simplex equivalent of the Bilateral with the following scales: LU,A{B,C1,C}D,LL. Blue card case and instruction leaflet.
John Davis & Son (Derby) Ltd mahogany and celluloid, ten inch, closed frame slide rule. Scales are: F,A{B,C}D,E//{S,T}. There are inch & metric rulers on the edges and tables on the reverse. The rule has DRP No 126499 in the well. This was a Dennert & Pape patent suggesting that they made this rule for John Davis who’s name only appears on the maroon cloth covered card case.
Reliance Rule Slide 10” (made for UK government - broad arrow mark). Mahogany & celluloid, closed frame, the inch & metric rulers on the edges are reinforced with metal mesh. Scales are: A{B,C}D//{S,L,T}. Cursor apertures and tables on the reverse. Brown, cloth covered, card case.
The Technical Standard Slide Rule. Closed frame, ten inch mahogany & celluloid with unusual cursor windows on the reverse, plus tables. Scales are: M,A{B,C}D,N//{S,ST,T}. (M & N are usually denoted LU & LL or LL2 & LL3). Made by the British Slide Rule Co, a subsidiary of Marine & Overseas.
An Otis King model K cylindrical slide rule (no. T1568) dating from the 1950s. These rules were made by Carbic Ltd. It is made of chrome plated brass with paper scales. Because of the spiral nature of the scales they were very long (66 inches) and hence calculations would be more accurate. It is complete with instructions and box.
A Professor Fuller's No. 1 Calculator made by W F Stanley in its fitted, mahogany box. The stand is missing. The box has the date 1940 in the lid but the rule serial no. 9957 50 suggests that the rule was made in 1950 and has changed boxes with another at some time These rules were accurate to five significant figures as a result of the extremely long (500 inch) spiral scales. It is complete with its instruction booklet. They were first manufactured in 1878 and changed little throughout their long period of manufacture except for the replacement of wood by Bakelite for the handle and ends. They continued to be manufactured into the 1960s.
Halden's Calculex. This one dates from circa 1925. It is double sided and the inner disc is rotated by the thumb nut in the centre. The cursors are marked on the glass faces which can also be rotated. It is complete with leather wallet and a copy of "revised Rules, Tables and Formulae for Patent Circular Slide Rule (Halden Calculex)" - a 2 1/4" square, 96 page booklet which is also housed in a pocket in the case and which cost an extra 1/6. On one side there are A, B,& C scales, whilst on the other are A with B reversed. There are a variety of other scales on each side as well.
A "Shetack" calculator for tapping and clearance drill sizes for different threads, made by DTC. It is a second edition September 1938 model. It is made of celluloid. These were later advertised by Fowler (Ref: Fowler’s Mechanical Engineer’s Pocket Book 1947)
Classic Series V 10” closed frame slide rule made from mahogany with celluloid covered paper scales and a metal/celluloid cursor. Scales are: in\LL2,A{B,S,T,C}D,LL3\cm. There are tables on the back. It has a card box (rather battered). It probably dates from the 1940s.
Classic Series II closed frame slide rule made from mahogany with celluloid covered paper scales and a metal/celluloid cursor. Scales are: in\LL2,A{B,C}D,LL3,\cm. It has tables on the reverse which are different to those on the Series V above.
Classic Series I mahogany slide rule with celluloid covered paper scales and a metal/celluloid cursor. This 10” slide rule has the following scales: in\A{B,C}D\cm. Tables on the back are the same as on the Series II. It has a brown card case.
Stanley Fuller Calculator no. 6454 32 made in 1932. Unlike the one above this has a wooden handle and ends and is in excellent condition complete with stand, which it is seen mounted on in the second picture.
Platt Count Converter and circular slide rule. The upper side is a conventional circular slide rule with scales as follows: L,D{C,C1,A,K}. The reverse has scales for five different types of cloth count to enable conversion between them. Diameter 3”. It has an instruction booklet (printed in Dorchester) and a PVC slip case. The actual manufacturer is not stated. Platt was an Accrington (Lancashire) firm which is a long way from where the instructions were printed. Was the maker a Dorset one (Abbott Brown or Blundell perhaps)?
Helix A 50LL slide rule. A 5” plastic slide rule with clear/blue vinyl slip case. Scales are: cm\LL2,A{B,C}D,LL3. It was probably made in Japan as it is stamped ‘Foreign’ on the back.
Helix Top Precision A 50S plastic 5” closed frame slide rule, complete with instructions and clear/blue vinyl case. Its scales are: K,S,A{B,C1,C}D,T,L. It was probably made in Japan as it is stamped ‘Foreign’ on the back. The printing really is unusually black.
An unusual spring design slide rule made from plywood, with paper scales, 12 inches long overall. It has four slides, two each side. The scales on the upper face are: load in lbs total; fibre stress lbs/sq in; SWG (standard wire gauge); mean dia of coil in ins. On the reverse they are: rate in lbs; no of coils; SWG; mean dia of coil in ins.
TS Emblem Series 1053 Olympic LL plastic 10” slide rule with reversible slide. It has a green and white blow moulded plastic case. The scales are: L,K,A{B,C1,C}D,S,ST,T//cm{S,LL1,LL2}in. It is a clone of the Aristo Scholar 0903LL apart from the branding and highlight colour. It was sold by Technical Sales who had previously been Aristo agents. Believed to have been made in Japan, probably in the 1960s
Classic Series III five inch mahogany slide rule with celluloid covered paper scales and a metal/celluloid cursor. Scales are in\A{B,C}D\cm. Tables on the back are for timber. It has a grey card case.
W F Stanley 5” mahogany and celluloid slide rule, made in England, probably in the 1920s. Scales are: in\A{B,C}D\cm//{S,L,T}. It has a brown cloth covered card case. It was probably made for Stanley by A G Thornton
This page contains a wide variety of slide rules including ones from the Simplon range of Dargue Bros, a Davis rule probably German made, a Reliance and a Technical. Also there are cylindrical rules - the Otis King made by Carbic, and the Stanley Fuller - and circular ones - the Halden Calculex and the DTC Shetack.
The Supreme slide rule. A closed frame, ten inch, mahogany and celluloid rule with plastic cursor, and tables on the reverse. Scales are: M,S,A{B,CR,C}D,T,N. (CR is usually shown as C1 or R; for M & N see above). Another British Slide Rule Co rule dating from the 1940s.
The Technical Aeronautical 10” closed frame mahogany/plastic slide rule dating from 1947 made by the British Slide Rule Co. It has a black card case. Scales are: in\M,P,A{B,P’,CR,C}D,K,N\cm//{S,ST,T}. The tables are for material properties,
The Technical Surveyor’s 10” closed frame mahogany/plastic slide rule dating from the 1940s made by the British Slide Rule Co. It has a grey card case. Scales are: M,A{B,CR,C}D,N//{S,cos,ST,cot,T}. There are map scales on the edges. The reverse has trig formulae and a table of sun’s parallax in altitude.
Classic Series I mahogany slide rule with celluloid covered paper scales and a metal/celluloid cursor. This 5” slide rule has the following scales: in\A{B,C}D\cm. It has a grey card case.
Classic Series II mahogany slide rule with celluloid covered paper scales and a metal/celluloid cursor. This 5” slide rule has the following scales: in\LL2,A{B,C}D,LL3\cm. It has a grey card case.