Turning and mechanical manipulation, by C. Holtzapffel by Charles Holtzapffel John Jacob Holtzapffel

Author:Charles Holtzapffel , John Jacob Holtzapffel
Language: eng
Format: epub, pdf
Published: 1850-03-25T05:00:00+00:00

1119.

In grinding the external cone the work in almost all cases revolves in the lathe, and the grinder charged with emery and water is held in the hands. The grinder is gradually twisted round to different positions, and continually traversed endways a small distance, according to the length and aouteness of the cone. The object of the short traversing motion is to distribute the emery uniformly and to keep the particles constantly shifting to different parts of the grinder, as if they were allowed to remain in the same position they^would be liable to mark the work with rings. On this account much less force is applied in grinding

q2

cones than cylinders, and the grinder is lightly held in an elastic manner so as to permit the emery to roll over between: the work and grinder.

At the commencement of the process the grinder should be somewhat smaller in diameter than the required cone, so as to allow for a little enlargement of the grinder^ as well as the reduction of the cone, which latter should at first only enter the grinder for about three quarters to seven-eighths of its length, according to the acuteness of the cone. The abrasion of the two surfaces allows the grinder gradually to advance towards the larger end of the cone, and as this is approached the grinder is from time to time slightly closed, to compensate somewhat for the wear. As the work progresses towards completion, increased attention is required to the condition of the grinder, and when it becomes so far worn as to mark the work with rings, or that the smaller end of the cone protrudes, a new grinder is cast for the completion of the work.

In the case of two cones of different angles joining each other as in fig. 1119, a form frequently employed in lathe mandrels, the grinder cast to a counterpart form is first employed to grind both cones at the same time in order to ensure their being concentric with each other. The long and nearly cylindrical cone «, serves as a guide for applying the grinder to the short obtuse cone i, which is completed with a grinder fitting both cones, and finally the cone a is separately corrected with a single cone grinder.

By far the more accurate methods of grinding the external cone are however the employment of the end of a fixed grinder, or the edge of a revolving lap mounted in the sliding rest^ while the work revolves in the lathe exactly in the manner explained on page 1237, for the production of cylindrical surfaces, except that the sliding rest is swung round to the suitable angle for the side of the cone. One of these methods is generally resorted to for works requiring the greatest accuracy, as it admits of the cone being corrected with considerable exactness, both for angle and straightness of the sides, and the circular section being derived directly from the lathe, the adjustment of the diameter is the principal object requiring attention.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.