Maudslay's Private Assistant

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ON the morning of Monday, the 30th of May 1829, I commenced my regular attendance at Mr. Maudslay's workshop. My first job was to assist him in making some modifications in the details of a machine which he had contrived some years before for generating original screws. I use the word "generating" as being most appropriate to express the objects and results of one of Mr. Maudslay's most original inventions.

It consisted in the employment of a knife-edged hardened steel instrument, so arranged as to be set at any required angle, and its edge caused to penetrate the surface of a cylindrical bar of soft steel or brass. This bar being revolved under the incisive action of the angularly placed knife-edged instrument, it thus received a continuous spiral groove cut into its surface. It was then in the condition of a rudimentary screw; the pitch, or interval between the threads, being determined by the greater or less angle of obliquity at which the knife-edged instrument was set with respect to the axis of the cylindrical bars revolving under its incisive action.

The spiral groove, thus generated, was deepened to the required extent by a suitable and pointed hard steel tool firmly held in the jaws of an adjustable slide made for the purpose, as part and parcel of the bed of the machine. In the case of square-threaded screws being required, a square-pointed tool was employed in place of the V or angle-threaded tool. And in order to generate or produce right hand or left hand screws, all that was necessary was to set the knife-edged instrument to a right or left hand inclination in respect to the axis of the cylindrical bar at the outset of the operation.

This beautiful and truly original contrivance became, in the hands of its inventor, the parent of a vast progeny of perfect screws, whose descendants, whether legitimate or not, are to be found in every workshop throughout the world, wherever first-class machinery is constructed. The production of perfect screws was one of Maudslay's highest ambitions and his principal technical achievement. It was a type of his invaluable faculty of solving the most difficult problems by the most direct and simple methods.

It was by the same method that he produced the Guide screw. His screw-cutting lathe was moved by combination wheels, and by its means he could, by the one Guide screw, obtain screws of every variety of pitch and diameter. As an illustration of its complete accuracy I may mention that by its means a screw of five feet in length and two inches in diameter was cut with fifty threads to the inch; the Nut to fit on to it being twelve inches long, and containing six hundred threads! This screw was principally used for dividing scales for astronomical and other metrical purposes of the highest class. By its means divisions were produced with such minuteness that they could only be made visual by a microscope.

This screw was sent for exhibition to the Society of Arts. It is still preserved with the utmost care at the Lambeth Works amongst the many admirable specimens of Henry Maudslay's inventive genius and delicate handiwork. Every skilled mechanic must thoroughly enjoy the sight of it, especially when he knows that it was not produced by an exceptional tool, but by the machine that was daily employed in the ordinary work of the factory.

I must not, however, omit to say that I took an early opportunity of presenting Brougham's letter of introduction to Faraday at the Royal Institution. I was received most cordially by that noble-minded man, whose face beamed with goodness and kindness. After some pleasant conversation he said he would call upon me at Maudslay's, whom he knew very well. Not long after Faraday called, and found me working beside Maudslay in his beautiful little workshop. A vice had been fitted up for me at the bench where he himself daily worked. Faraday expressed himself as delighted to find me in so enviable a position. He congratulated