SPECIAL REPORT OF MR. HILL, OX MACHIXERY. 425
either convex or concave, adapted to crank boxes, etc. It resembled a heavy upright drill. The spindle was very heavy, and carried at its lower end a slotted arm, in which could be fixed a holder with cutting tool, with such radius as the work demanded. This spindle received a reciprocating turning motion by means of a proper gear, passing through such an arc of a circle as it was set to, and there reversing itself and turning back, with a quick, return motion. It also had a self-acting down feed. In this way the tool would plane round the portion of a circle of any given diameter it was set to, within the radius of the arm. The horizontal table for the work was adjustable in all directions.
A common machine in the Exposition, and in the English work-shops, was a frame of gang-drills for drilling a line of holes at once. These were generally driven by a long screw, running along the top of the spindles and gearing, into a skew gear on each of them.
A very fine bolt-heading machine was exhibited by De Bergue & Co., of Manchester. The rods being cut up after heating, by knives on the machine, were dropped into holes in the rim of a heavy revolving wheel, which carried them successively under the punch which headed them, after- which they were dropped out below. The details of the tool were well worked out, and the production was guaranteed at forty- five bolts per minute.
A machine for planing the teeth of heavy gears, was shown amonsr the tools of the Chemnitz Werkzeugmaschinen-fabric. The arrangements for adapting it to the size and form of gears Were «rood. The tool-holder in this machine oscillates on a centre, and the form of the /tooth to be cut is determined by an arm which follows the surface of a copy or guide.
This short list, it is believed, includes nearly all the tools m the Exposition which would be really new to a New England visitor, and which would be likely to be of any value to us. It is not impossible that there are tools like them already hi use among us. To the writer they were most of them new, and have been thought "worth a brief mention.
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