Sloan & Chace was one of a number of American companies well known for their small, high- precision machine tools, especially those used by the watch, clock and instrument-making trades. These included: Levin, Bottum, American Watch Tool Company, B.C.Ames, Bottum, Hjorth, Potter, Pratt & Whitney, Rivett, Wade, Waltham Machine Works, Wade,  Pratt & Whitney, Rivett, Cataract, Hardinge, Elgin, Remington, Sloan & Chace, W.H.Nichols, Crystal Lake and (though now very rare) Bausch & Lomb, Frederick Pearce, Van Norman, Ballou & Whitcombe, Sawyer Watch Tool Co., Engineering Appliances, Fenn-Sadler, "Cosa Corporation of New York" and UND..
Like many such manufacturers, Sloan & Chase offered a range of lathes either specially made to order or adapted for production work, together with a range of accessories to extend the scope of their regular line.
In addition to lathes Sloan and Chace also offered small milling machines, wheel & pinion cutters, automatic and manually operated gear-cutting equipment and drills and tappers, All their products, though not of revolutionary design,  followed the accepted quality standards of the day and were successful enough to make up the bulk of the type offered in the comprehensive, hard-back catalogues issued during the 1920s and 1930s by one of England's largest machine-tool distributors.
Sloan & Chace lathe pictures continued here

Sloan & Chace No. 51/2 precision bench lathe
Unlike the majority of bench precision lathes whose beds had a flat top and beveled edges, that on the Sloan and Chace was very distinctive, being formed with two symmetrical V-ways. Shown above, the milling and grinding slide has been mounted on a compound slide rest (arranged back-to-front) with a collet-holding dividing unit fitted with interchangeable "notch" plates indexed by a spring-loaded pawl.
In tradition of precision bench-lathes the headstock pulley was arranged with its smallest diameter towards the spindle thread so that the all-important front bearing could be surrounded with as great a mass of metal as possible. The edge of the largest spindle pulley was drilled with a single ring of 60 division holes (competitor machines had up to three rings) and the front of the bed immediately below the headstock had a short T slot machined into the first few inches of its front face so that a screwcutting attachment could be bolted in place.

Sloan & Chace No. 51/2 precision bench lathe fitted with an unusual design of screwcutting attachment. Instead of utilising the existing compound slide rest and driving the top slide by changewheels and a universally-joined shaft--as was commonly practiced by other makes--the Sloan & Chace employed a complete set of new parts including a proper leadscrew and a "sub bed" sitting on top of the main bed that carried its own saddle and cross slide unit.