If Seneca Falls were content to produce lathes of rather ordinary design (albeit well-made and carefully detailed) then the company's wonderful Universal Milling and Gear-Cutting Attachment, made in three sizes, went some way towards enhancing their reputation, for this was a most unusual, versatile and adaptable accessory, suitable for a wide range of work.
The patented unit was in two parts: the powered "Cutter Block" and column-like "Universal Head".
The "Cutter Block" was mounted on the lathe saddle and could therefore be fed (within the limits of the sliding power shaft) in either direction, longitudinally or cross ways, by hand or automatically using the lathe power feeds. The cutter arbor, which could be rotated in either direction, was powered through bevel gears and a sliding, universally-jointed shaft  from a collar clamped round the headstock spindle. The arbor socketed into a Morse taper hole, was supported at its outer end by an overarm and provided with a draw bar.
The swivelling-base "Universal Head" (when used in conjunction with the Cutter Block) was clamped to the bedways and carried, on a swivelling spigot, either a machine vice or dividing head. It could also be mounted on the cross slide, in place of the top slide, and used as an ordinary milling attachment; with suitable cutters held in the headstock spindle, the ends of shafts could be machined and surface milling and keyway cutting undertaken.
The spindle carried the same nose thread as the lathe it was supplied to fit, so that collets and chucks, etc., could be transferred from one to the other.

In this illustration the powered "Cutter Block" and the "Universal Head" are being used together to slot or spline a shaft. The Universal Head (H) is fastened to the lathe bed whilst the Cutter Block (CB) is mounted on the lathe cross slide and driven from the headstock spindle at (H).
A steady bar (B) is fastened between the Universal Head and a bed-mounted block (D) and its slotted extension arm (E).
The bar carries a sliding clamp (C) and an adjustable centre (G). The shaft to be machined (A) is held between the centre at (G) and a lathe-like dog at (F) and indexed round by the Dividing Head (P).