A remarkable Waltham accessory - the powered filing attachment.
Those experienced with ordinary "filing machines" will know that they are not what, to the layman, they might seem, a rough-and-ready method of removing metal, but the exact opposite. A top-class filing machine was an expensive item - and an experienced operator could achieve almost miraculously-accurate results with one. They were not designed to be employed in general workshops but found a valuable niche in better-equipped toolrooms.
The Waltham unit was equipped with a five-inch diameter table that could be tilted to file any clearance angle; whilst angled it could then be rotated for one complete turn in the horizontal plane, making it possible to file a square corner, with a clearance angle at each side, with one setting of the work.
The attachment was also available as a complete machine, as illustrated below. Its three-step pulley was designed to be driven not, as it may appear to the modern eye, by a V belt, but by a round leather "rope".