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Based in Göttingen, Lower Saxony, Germany, the Feinprüf Company was a builder of machine tools intended for fine finishing or special purposes including (amongst many others) high-speed relieving lathes, precision hand-lever presses, grinders, gear planers, multi-purpose testing instruments (for simultaneously testing electrically and mechanically any number of dimensions with an accuracy of up to 0.00005"), production fixtures and problem-solving solutions for manufactures setting up complex or new production systems.
Hand operated, the Tricurat 60 surface grinder was a high-quality, toolroom class machine intended for the most accurate of jobs. Although all surface grinders are precision machine tools, the Feinprüf was (as its maker's reputation suggested it would be) especially well constructed and in a different class to the similar English makes of Eagle and Capco. Heavily built with a cast-as-one base and column, the machine featured well-proportioned wearing surfaces that were either hardened steel or heat-treated cast iron given a very fine machined finish or lap ground. Guideways were all protected by close-fitting bellows and the 23" x 7" table ran on vertically and horizontally mounted precision ball bearings whose tracks were hardened and lapped; the bearings were adjustable and the table could be set so that it floated in a true plane without any side or upward deviation. Able to accommodate a workpiece 10 inches high, the table could be moved longitudinally through its 16 inches of travel by either the usual lever or, with that disconnected, by hand - so free-running was the assembly. Adjustable spring-loaded micrometer stops were provided, able to be set to within 0.0005". For the vertical and traverse motions (the latter a maximum of five inches) fine-pitch screws were used and fitted with large-diameter micrometer scales reading to an accuracy of 0.0005" - though where a higher degree of accuracy was required built-in comparators used in conjunction with slip gauges enabled positioning down to 0.00005". The obtaining of fine settings was eased by the provision of an unusual mechanism, where one push of a button advanced the table up, down or across in increments of 0.00005".
Running in precision ball bearings (fitted with "micrometer" adjusting collars at each end of the assembly) the spindle was of a large diameter and noted for its very smooth running. The spindle could accept wheels from 2" to 6" in diameter and from 3/16" to 5/8" wide, the guard fitted being of a most perfunctory nature and unlikely to have contained a burst wheel
Like Capco, Feinprüf offered a number of useful accessories, all made to a very high standard. These included: a 4" x *2 magnetic chuck, a pair of Magnetic Parallel Blocks (permanent magnet type) 4" x 2" x 1.5"; a Diamond-wheel Dressing Holder; Radius Dressing Attachment; a 3.25" centre height by 10" between centres Indexing Head and Back Centre Attachment equipped with a 24-tooth dividing plate; a 10" diameter Circular Indexing Plate for use horizontally and fitted with a 24-tooth plate; a Precision Machine Vice with jaws 3.125" wide opening to 3"; a Compound Sine Table with a working surface of 5" x 9" able to be set in two planes and able to mount clamps, a vice or magnetic chuck; a Single Plane Sine Table 5" x 9" x 1.375" high; Precision V-blocks for the table sized 6" x 3" x 2.25" and two others 1.5" x 1.25" x 2.25" and 1.75" x 1.5" x 2.75" for use on the horizontal circular indexing plate; a Radius and Tangent Wheel-dressing Attachment that could dress the wheel on either side and on the face with radii from 5/64" to 2" with subtended tangent for every angle that could be set on the scale (back to high-school math…..); a Crushing Attachment for crushing concave or convex profiles into the wheel; a Machine Light and Coolant and Dust Extraction equipment. A further option was the substitution of the standard 0.8 kW 3000 r.p.m. motor with one having infinitely-variable speed control from 900 to 9000 r.p.m..
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