{"product_id":"1930s-fowler-s-kearns-machine-time-computer-in-original-case-vintage-english-circular-slide-rule","title":"1930s Fowler’s Kearns Machine Time Computer in Original Case | Vintage English Circular Slide Rule","description":"\u003cp\u003eFor the technician … a rare Fowler Kearns Machine Time Computer, c. 1925-1940, made by Fowler \u0026amp; Co. for H. W. Kearns \u0026amp; Co. of Broadheath, Manchester.  Measuring 2-5\/8 inches across, this pocket-watch-style circular calculator was designed for use with Kearns horizontal boring machines, large machine tools used to bore and finish precise holes in heavy engineering components. Fully functional and complete with its original fitted case, it would make a memorable gift for an engineer, machinist, or collector of vintage industrial instruments.\u003c\/p\u003e\n\u003cp\u003eWilliam Henry Fowler established the Scientific Publishing Company in Manchester in 1898, and his son Harold began manufacturing circular calculators around 1908. Fowler \u0026amp; Co. went on to produce a wide range of pocket calculators for engineering and industrial use, including highly specialized models developed for specific trades and machinery. The Kearns Machine Time Computer was one of these specialist models, with scales for cutting speed, workpiece diameter, length of cut, and machining time. Fowler reference literature describes this model as “unusual and rare.”\u003c\/p\u003e\n\u003cp\u003eIn 1920, the Fowlers moved production to larger premises at Station Works in Sale, near Manchester. Four years later, William Henry and Harold Fowler patented an improved mechanism that allowed the dials on opposite faces to be operated independently using two side-mounted controls.\u003c\/p\u003e\n\u003cp\u003eCircular slide rules offered several practical advantages over conventional straight rules. Their scales were protected beneath glass, and the continuous circular arrangement avoided the need to reverse a slide when a calculation ran beyond its end. Fowler’s instruments were also unusually costly to manufacture: early models required numerous precision-made parts and hand assembly, and were priced at approximately four times the cost of comparable straight slide rules.\u003c\/p\u003e\n\u003cp\u003eDimensions: (Rule, not including suspension ring) 2-5\/8” D x 7\/16”; (Case, closed, not including suspension ring) 2-3\/4” x 2-3\/4” x 9\/16”\u003cbr\u003eWeight: (Combined) 5.5 oz.\u003c\/p\u003e\n\u003cp\u003eCondition notes: Calculator in excellent antique condition overall, with light surface wear to metal rim and case consistent with age and handling, including fine scratches and small marks to polished surfaces. No dents, cracks, or structural damage noted. Glass remains clean and clear, with no visible chips or significant scratches. Dial remains clean and evenly toned overall, with a few small age-related spots around outer perimeter and one small dark mark beneath glass near the ‘300’ marking; all scales and numerals remain crisp, clear, and easy to read. Both knurled control wheels operate as intended, and instrument remains fully functional, although not tested for accuracy. Suspension ring remains securely attached.\u003c\/p\u003e\n\u003cp\u003eFace is marked “H. W. KEARNS \u0026amp; CO LTD,” “BROADHEATH, MANCHESTER,” “MACHINE TIME COMPUTER,” “PATENT,” and “FOWLER \u0026amp; CO MANCHESTER,” with fixed notation “CUTS PER INCH 8.” Concentric scales are marked for time in minutes, feet per minute, length in inches, and diameter in inches. All printed scales, numerals, and markings remain clear and legible.  Reverse retains polished finish with fine scratches and handling marks consistent with age and is engraved “BORING Kearns MACHINES” with serial number 10817. \u003c\/p\u003e\n\u003cp\u003eOriginal fitted metal case shows fine scratching, scuffing, scattered small marks, and edge wear consistent with age and use, with no significant dents or structural damage noted. Purple lining remains in very good condition overall, showing circular compression marks from storage of calculator and light age-related surface wear. Original interior label reads “Fowler \u0026amp; Co CALCULATOR SPECIALISTS Manchester, ENGLAND.” Hinges and closure operate as intended. Other objects in photos not included.\u003c\/p\u003e\n\u003cp\u003eUnless noted, all items are hand-wrapped, gift-boxed, and packed with care for secure delivery. We offer flat rate shipping via USPS Ground Advantage for $10, or USPS Priority Mail for $15. Orders over $100 (not including taxes) ship free via USPS Priority Mail — any shipping charges for orders over $100 will be refunded after checkout. We pack with safety and care using recycled and recyclable materials whenever possible.\u003c\/p\u003e\n\u003cp\u003eSorry, no returns or cancellations.  Please view all photos for more detail and feel free to contact the shop with any questions prior to purchase.\u003cbr\u003e\u003c\/p\u003e","brand":"Pickess \u0026 Parr","offers":[{"title":"Default Title","offer_id":44613416681559,"sku":null,"price":349.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0598\/9302\/2807\/files\/PSX_20261017_103734.jpg?v=1793828981","url":"https:\/\/www.pickessandparr.com\/products\/1930s-fowler-s-kearns-machine-time-computer-in-original-case-vintage-english-circular-slide-rule","provider":"Pickess \u0026 Parr | Vintage Objects for Gentlemen","version":"1.0","type":"link"}