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Scrivener 618 and 824 Surface Grinders

Manuals for Scrivener grinders are available

Scrivener Cylindrical Grinders 


Believed to have been introduced in 1936, by the early 1960s the Wickman surface grinder range consisted of two models: a newly introduced, heavily modified version of an established machine, the 618, that was also offered as a model with increased capacity and more powerful motors, the 824. However, the original 824, first manufactured in the early 1950s, was a very much more massive machine and appears to have disappeared from the lists on the arrival of the new version. Although the Type designations of each machine appear to represent their capacity - the first digit being the table's cross travel in inches while the second pair referred to its longitudinal - in each case the measured travels were actually different, being a mixture of longer or shorter according to the particular model and its year of production. A wholly new design in every respect, the new 618 and 824 models had hydraulic, lubrication and drive systems that were intended to reduce maintenance to a minimum while providing long, trouble-free service.
Cast as one piece, the main frame was in iron, internally ribbed for rigidity and fitted with well-spaced saddle ways and guides for the elevating rear column, the former precision ground and protected by bellows.
Mounted on needle-roller, anti-friction ways, the saddle provided seatings for the hydraulic-control "monobloc unit", the table traverse hydraulic cylinder together with good-sized V and flat ways that gave full support to the table - even at the extremes of its working stroke. Provided with T-slots, extra facings for clamping magnetic chucks or fixtures and coolant channels for wet grinding, the table had a spark guard fitted at one end with equipment for wet grinding, including full splash guarding, available at extra cost.
Running on bellows-protected, prismatic slideways the rear column, together with its wheelhead and motor-drive unit, was raised and lowered by a large diameter leadscrew fitted with ant-friction thrust races. On the smaller 6 x 18 machine hand-feed was the normal fitting, though a rapid power-driven rise and fall - as fitted to all 8 x 24 models - could be provided at extra cost. In addition, a choice was offered of two extra tall columns, that extra clearance under the wheel being 13" and 16" respectively.
Hydraulic valve control gear was contained in a single "monobloc" unit and provided all the controls necessary to provide both an infinitely variable rate of table traverse (of up to 125 feet per minute) and also a cross feed. The latter function was by means of a combined hydro-mechanical system that also allowed a table "run-out and park'' arrangement to be engaged, this moving the work clear of the grinding wheel and allowing it to be measured. Jig-drilled in position, the "monobloc" unit was, claimed the makers, easily demounted for servicing.
Continued below:

Late model of the Scrivener Model 618 and 824 Surface Grinder

Continued:
Housed in the base of the machine and coupled by just two connections to the hydraulic system, was the vane-pump-driven power unit, this being provided with pressure check points and running - to reduce aeration of the hydraulic fluid - at a relatively low pressure.
Automatically lubricated by an oil bath, the wheelhead assembly followed practice established over twenty years on Scrivener centreless grinders with the use of adjustable, plain, hard phosphor­bronze bearings shrunk into the casting at -81° (though early models had what were described as lead-bronze bearings). The spindle, manufactured from a forging in nitralloy, was particularly stiff and designed to allow the fitting of oversize diameter wheels for use when dieset grinding. 
The patented Scrivener spindle thrust bearing was claimed to capable of easy and precise adjustment by unskilled labour - this presuming that all hammers were safely hidden away from them first….
Mounted at the foot of the vertical column, the main motor drove the spindle pulley directly through twin V-belts, their tension being set by the simple means of adjusting the motor platform's vertical position (when replacing such belts a matched pair are absolutely essential or, if not available, the use of T-link belts).
Entirely separate from the hydraulic circuit, the lubrication system provided a metered supply of oil to the table ways, this working continuously in either manual or power modes. Column and saddle-ways, column and saddle leadscrews and nuts were all oiled by a single-stroke, hand-operated pump - this reliability of this arrangement depending, of course, upon the inclination of the operator or efficiency of the service department.
All controls were grouped at the front of the machine, the table traverse control being coupled to a safety interlock that prevented power feed from being started when the table handwheel was engaged - the interlock also locking out engagement of the handwheel when the table was under power drive. Both the cross feed of the saddle and vertical movement of the wheel head could be directly adjusted by means of the handwheels to within 0.0001" (0.002 mm.) and 0.00025" (0.005 mm.) respectively while micrometer adjustments give further accuracy to within 0.0001 " (0.002 mm.).
One ingenious feature was a vertical fine-feed knob that incorporated a "click" plunger, this allowing the operator to set a cut of just 0.0001" (0.002 mm) by feel alone, his eyes thus remaining fixed upon the workpiece. Exclusive to Scrivener was the arrangement of the table speed control, this being set co-axially with the start-stop lever and giving independent control of the table traverse rate while permitting the machine to be instantly restarted at its original, pre-set speed.
All grinders were supplied with a complete electrical installation to a customer's voltage requirements, ready to run, with full overload and no-volt safety protection, waterproof push-buttons and the main isolating switch interlocked with the access door. To allow dust extraction and coolant equipment to be connected without having to modify the system, addition plugs and sockets were provided as standard.

Supplied with each new machine was a universal wheel guard suitable for wet or dry operation; one grinding wheel of standard diameter and width); an additional spare standard wheel; one mounted and one spare standard wheel-fitting adaptor and flange; a wheel balancing arbor; a diamond dressing holder (excluding the diamond); a set of four foundation bolts jacking screws and plates; two table T-bolts and nuts, spanners, keys, special tools, the initial hydraulic and spindle oils and a set of operating instructions.
Optional Extra Equipment consisted of: the previously mentioned two longer columns; an oversize grinding wheel for dieset grinding (10" diameter on the Model 618 and 14" on the 824); plain wet grinding equipment including a coolant tank, pump and motor, piping, fittings and splash guards; a coolant filtration system; coolant  through-the-wheel; dust extraction; a wheelhead-mounted wheel-truing attachment for the 618; power rise and fall to the column on the 618; automatic down-feed; low voltage lighting; a more accurate thread-ground cross-feed leadscrew and split nut (in lieu of the standard cut thread screw and solid nut) for gap-gauge grinding; a variety of electric and non-electric magnetic chucks; standard machine and precision vices of various types; wheel-forming,  sine and  radius-dressing  attachments; projectorscopes; "Profiloscope" form-grinding equipment and indexing centres..

The early and quite different Scrivener 618 surface grinder as first manufactured in the early 1950s and replaced in 1960/1

Late-type Scrivener 618 and 824 as manufactures from 1960 onwards

Early Scrivener 824 surface grinder from the 1950s

Plan view of the early Scrivener 824

Automatic oil pump for the table ways

Hand-operated pump to lubricate non-automatically oil parts

Late type Scrivener 618 and 824 table hydraulic ram assembly

Late-type 618 and 824: front of the hydraulic "Monobloc" control unit and its connection to the cross-feed handwheel

Late-type 618 and 824 Hydraulic tank, motor and pump

Original 824 vertical hand feed and saddle traverse gearbox unit


Original 824 vertical hand feed and saddle traverse gearbox unit

Original 824 dust-extraction unit

A typical Scrivener grinding wheel mounting assembly


Manuals for Scrivener grinders are available

Scrivener Cylindrical Grinders 

Scrivener 618 and 824 Surface Grinders
email: tony@lathes.co.uk
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