This compound slide is for the Rivett 8" Precision lathe, circa 1898 http://www.lathes.co.uk/rivettearly608/index.html). It was not a watchmakers' lathe, as the distance between centers was 22" and the swing was 8.5". The base of the cross slide is 4" long and 1.75" wide, excluding screw and handle. The slide sold on eBay (item 979360670) in November for $375.