email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools Sale & Wanted
Machine Tool Manuals   Catalogues   Belts   Books  Accessories

Sanford SG-48 Miniature Grinder
Photo Essay


Sanford SG Grinders Home Page

Photographs by Ted Howard (United States)

Developed through two previous revisions, the final version of Sanford's miniature surface grinder, the Model SG-48, was put on the market in 1961.
Although all later editions of the sales brochure listed this model correctly as the SG-48, in the first issue is was described on the cover as the "SG-2" - though this was not repeated on other pages, nor on machine nameplates. Heavily revised, changes included a differently drilled and tapped base assembly (that may well have been a revised casting) and altered motor mount, spindle carrier and upright - the latter being a completely new design with a single, channel-shaped riser replacing the left and right castings of the earlier type; a gib strip was also added that allowed the side to side fit of the spindle carrier to be adjusted, this previously being machined to a "dead, non-adjustable fit".
In addition, the operation of the vertical leadscrew was reworked so that it no longer rose above the top of the upright, instead it remained within - its basic operation being reversed as follows: on early machines the screw had been fixed rigidly to the spindle carrier and threaded through the (handwheel-turned) top bevel gear.  Hence, as the bevel gear turned it drew the screw upwards so that it protruded above the column while, at the same time, lifting the spindle carrier. In the modified design the leadscrew was threaded into the spindle carrier and pinned to the top gear and so rotated with it. The result was that as the screw rotated it caused the carrier to rise but, being fixed to the gear, just rotated inside the casing. As this change removed the need for the tall, cast-aluminium screw guard to be fitted, the top-mounted gears were now enclosed by the simple means of the sheet-metal front and side face cover being extended upwards and formed with a cap. Replacing the earlier flat-belt drive from motor to spindle, a V-belt was used, this being exceptionally short as the motor, now on top rather than suspended beneath its support plate, was so much closer to the driven spindle.
The cross feed and vertical handwheels acquired adjustable degree sections (though this was a "running change" and the motor specified was, at last, a more powerful, a hp, 3450 rpm type..


High resolution pictures - may take time to download



Sanford SG Grinders Home Page

Sanford SG-48 Miniature Grinder
Photo Essay

email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools Sale & Wanted
Machine Tool Manuals   Catalogues   Belts   Books  Accessories