Sloan & Chase tapping machines were available in three versions: "Vertical Lever", "Table Lift" and "Horizontal". All were produced to help with the accurate and reliable tapping of small holes in watch, clock and instrument mechanisms. The Vertical lever model was based on the company's single-spindel precision bench drill and consisted of a 3.75" diameter cast-iron base plate that carried a solid steel column formed with a larger diameter over bottom half of its length. A round clamp-on table could be slid up and down the lower half by hand pressure whilst the top was fitted with a spring-loaded, lever-operated head that held two pulley each of which - by virtue of a special countershaft - rotated in opposite directions. A double-sided conical clutch was moved up and down by the lever and caused the tap be either driven slowly down into the job or wound out of it. Adjustable screw stops allowed the operator to limit the travel of the spindle and so set up a job for completion in the shortest possible time and without the danger of the tap running too deeply into the job. With practise an operator became very familiar with the pressures needed to engage and withdraw taps into different materials and broken tools and spoiled jobs were a rarity.         
The other type of vertical tapper used a fixed head combined with a lifting round table that, because of the small forces involved, was moved by hand and not with the assistance of a lever. The table was prevented from rotating by a rectangular strip  of steel hinged between it and the column's base casting whilst the head contained a double-sided cone clutch that could engage against pulleys above and below that were rotating in opposite directions. Lifting the table up caused the tap to wind into the job, pulling downwards screwed it out.
For jobs where a vertical machine might have been awkward to use a special applications a horizontal model was also available; this had a simple hand-moved table but a "headstock" with a more robust bearing assembly than the other models..