While sharing the surname of Charles Moseley, the inventor in 1857/8 of the game-changing hollow-spindle watchmakers' lathe with its draw-in collet assembly - and both at one time being based in Elgin - it is not though that the two were connected. In 1864, the National Watch Company of Chicago had invited Charles to join them as general superintendent of their Elgin factory - but had left there in 1877 some 12 years before Horace patented his length-stop mechanism.
By 1888, Moseley's new lathe had found widespread acclaim and employment (the lathe was first sold in 1859 and resembled what is now known as a "Geneva" type with its round bed and generally light build). Although it must have been of great importance to him, it appears that Moseley never patented his invention; it was left to a man called Messerer's, some 31 years later in 1889, to mention this in his conversion of a pair of turns to incorporate, between the centres of the turns, a 3-step pulley with a hollow spindle and draw-in collet. But, one year earlier, in 1888, our Horace Moseley of Elgin had patented an adjustable length stop to be used in association with a draw-in collet, and in this, he refers to established and "usual" parts as though these would, by then, have been in almost everyday use. It seems that these inventors had either not noticed each other's work or knew that the system was not patented   
A thorough search of US patents in regarding this matter has not revealed any material regarding Charles Moseley's first invention - not even a picture of the first "Geneva-type" hollow-spindle lathe - and so it remains a puzzle as to why he neglected this critical point. Might Messerer have seen Horace Moseley's patent and realised that the draw-in collet had not in fact been patented and decided to do something about it? If so, his patent fell short, for its design had a solid draw-bar to hold the collet and so precluded the possibility of using a hollow tube to retain the collets and so long material to pass clear through the spindle..