Grinding lathe

Figure 10.31 The surface grinding process where a grinding lathe removes excess hard facing material from the outside diameter of the screw (courtesy of Jeffrey A. Kuhman of Glycon Corporation)...

FIGURE 1.5 A highly ornamented Lens-grinding lathe on display at the Institute and Museum of the History of Science in Florence, Italy (from Ref. 26). 

The calcium crowns can be sold as such for certain appHcations. However, further processing may be required, and the crowns can be reduced in size to pieces of about 25 cm or nodules of about 3 mm. They can also be melted under a protective atmosphere of argon and cast into billets or ingots. Calcium wire can be made by extmsion, and calcium turnings are produced as lathe cuttings from cast billets. Technologies have also been developed to manufacture calcium metal particulates and powders by atomization, comminution, and grinding processes. 

Glass surfaces which must fit closely are usually ground to shape. The most common example is the cone-and-socket joint the surfaces are first worked to an approximate fit with fairly coarse carborundum (about 100 mesh) which is put between them and wetted. The cone is rotated by hand or in a lathe or drill chuck, or by a special machine, until the smfaces meet closely—the carborundum must be kept moist all the time. The coarse abrasive is then washed off, and the grinding continued a number of times with progressively finer abrasive. Various possible abrasives are mentioned on p. 39. 

A casehardened steel-grinding tool of precise taper (Fig. 11.7) is fitted to the chuck of an otherwise redundant lathe headstock and rotated at about 60 rev/min. A suspension of No. 400 silicon carbide (carborundum) in a mixture of glycerine and water is applied to the tool and the socket blank held in place with the right hand. 

Shape the ferrules on a lathe or by grinding. Anneal the front ferrule by heat ing to a cherry red and plunging it into cold water. Then drill a i -in. bole through the center. Place the piece on the anvil and drive down flat so that it vdll slip into place on the tang. 

This report discusses four technologies single water jet, spinning twin water jets, lathe machining, and rotary knife grinding (RKG). The size reduction methods are compared among each other for safety, efficiency, and performance. 

Since the taper of stop-cocks made in one works is very nearly the same irrespective of the size, a single conical rod of iron chucked in a crude lathe (Fig. 36) serves to grind out all the sockets to the same taper or angle, the size varying according to the distance to which they enter along the conical rod. A few strips of sheet iron, tV inch to -3 inch thick, and about 2 inches wide, are bent to fit this grinding cone at various distances... 

These cutting tools can of course be resharpened, but a specialised tool-and-cutter grinding machine is required. The basic cutting tools used on centre lathes and those used on the shaping machine are ground by hand, to give a variety of angles and shapes to suit different materials and applications. 

All the shafts and the hubs, both for HJs and for SFJs, were made of C40 UNI EN 10083-2 steel [17], without any surface treatment. Specimens were machined by means of a CNC lathe, with final grinding treatment in order to reduce surface roughness and to accomplish tolerance requirements. 

Engineering workpieces cannot be consistently produced to an exact size. This is due to a number of reasons such as wear on cutting tools, errors in setting up, operator faults, temperature differences or variations in machine performance. Whatever the reason, allowance must be made for some error. The amount of error which can be tolerated - known as the tolerance - depends on the manufacturing method and on the functional requirements of the workpiece. For example, a workpiece finished by grinding can be consistently made to finer tolerances than one produced on a centre lathe. In a similar way, a workpiece required for agricultural equipment would not... 

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