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Reiniger, Gebbert & Schall
Miniature Precision Cylindrical Grinder
Factory Correspondence

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Built during the 1930s, and not dissimilar in many ways to the English Jones & Shipman Model 520 of the same era, the Reiniger, Gebbert & Schall miniature precision cylindrical grinder was intended for instrument, optical and specialist toolroom operations. Built at the maker's factory in Erlangen, but sold through the huge Ludwig Lwe organisation of Hutten Strasse, 17-20, Berlin  - themselves a large producer of all kinds of metal-working machines - this small model complimented Lwe's own range of larger grinders.
Weighing a total of 320 kk together with its massive cast-iron base that doubled as a coolant tank and location for the main electric motor, the grinder had its own, self-contained drive system, carried on "overheads" - a smooth-running flat belt being used to drive the wheelhead at a single speed of 4200 r.p.m. and a round belt employed for the workhead (though the machine shown in the photographs below has been fitted with a V-belt). Drive to the upper part of the overhead was by a flat belt from the motor, the input pulley driving a shaft that carried the wheelhead drive pulley. From this input shaft a 3-step, round belt-pulley drove a second parallel shaft to which the wheelhead pulley was fitted, this system allowing three independent speeds to be provided, a little slower than those on the J & S at 254, 518 and 930 r.p.m. Unlike the Jones & Shipman that used two separate and large cast-iron uprights to carry the overhead drive, the design of the RGS allowed the use of simple and inexpensive steel tubing to perform the same task, the assembly being clamped into two sockets, one on each side of the grinder's large base plate. However, while the more complex Jones and Shipman was fitted with power feed to the table's sliding motion, the RGS had only a hand-feed through rack-and-pinion gearing - though the attention to detail was exclamatory with the table stops positively secured into indents to provide an absolutely solid location.
The design of the wheel head and its mounting was interesting for, with only delicate work being undertaken, there was no need for massive castings, instead it was possible to slide the whole assembly off its ways and instantly change it for one of another type; or, as it was fitted with a quick-release, hinge-open bearing housing, as an alternative just the spindle, complete with its plain bearings and grinding wheel, could be quickly removed and replaced by another. The outside of the wheelhead bearings were spherical and their mounting designed so that, as they were fitted, a degree of self-alignment was achieved that ensured absolute freedom of rotation. Just inboard of the feed-screw handwheel - and against the face of the micrometer dial -  was a stop that swung in for repetition work. Combined with this was an ingenious facility for the feed-screw nut (and hence the slide) to be moved forewords and backwards through 20 mm by a large cranked lever at the side of the head.
In 1933 the total price of an equipped machine, 3210 Reichmarch, would have purchased a new small car - the BMW Dixi, a developed copy of the English Austin 7. A letter from the factory, together with prices, can be seen here



Complete, in working order and on the maker's self-contained stand.

Simple, hand-operated table . Note the stops, positively secured into indents to provide an absolutely solid location

A rear view of the wheel feed. Just inboard of the feed-screw handwheel - and against the face of the micrometer dial - can be seen a stop that was swung in for repetition work. Combined with this was an ingenious facility whereby the feed-screw nut (and hence the slide) could to be moved forewords and backwards through 20 mm by the large cranked lever at the side of the head.


The wheel head assembly removed. Note the spherical bearing housings that allowed a degree of self-alignment during assembly and ensured that the spindle was free to turn with minimum resistance.  Quick-release fastenings also permitted the immediate substitution of the entire head for another of different design.

The wheelhead in place. On the left the rotating carrier and on the right the adjustable-tension support centre

The table set at an angle for taper grinding

Table removed revealing the typical V-ways used on many grinders



Factory Correspondence

Reiniger, Gebbert & Schall
Miniature Precision Cylindrical Grinder

email: tony@lathes.co.uk
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