ACCESSORIES AND ATTACHMENTS FOUR - JAW INDEPENDENT CHUCK The four - jaw independent chuck (93), a s the name indicates, has four jaws, each being independently ad - justed with a chuck wrench. The jaws are reversible so that the chuck can be used for inside or outside chuck - ing. It is attached to the spindle of the lathe by means of a chuck plate. The flange of the chuck plate is fitted to the recess in the back of the chuck and the chuck is bolted to the flange. This adapter plate is especially recommended for old style Regals which were built with the threaded spindle nose.
For the newer Regals with taper key drive spindle nose, chucks are available for direct mounting on the spindle nose as shown above. DRILL CHUCK AND SHANK For holding center drills and straight shank drills, a drill chuck with a shank fitting the Morse taper hole in the tailstock spindle i s almost a necessity. These chucks a r e made in the three - jaw self - centering type (125), and the two - jaw type (126) which is more desirable for large size drills, taps and reamers. The four - jaw chuck i s used to hold rough pieces that are not perfectly round, or pieces that must be centered on the chuck so that some section will be concentric with the lathe center line.
This is accomplished by ad - justing each jaw individually with an indicator against the work to determine the amount and direction of run- out. TH R EE - JAW UNIVERSAL CHUCK The small face plate i s used to drive pieces of work such a s shafts and mandrels by means of a lathe dog clamped to the work. The tail of the dog engages a slot cast in the face plate. Three cored slots radial to the center make it convenient to mount special drivers or fixtures to the face of the plate. The three - jaw universal chuck i s used to hold pieces that are semi - machined, and parts made of cold - rolled steel or drill rod which is ground to close limits.
When the chuck wrench is used, all jaws move to or from the center in unison, gripping the pieces quickly. The chuck is attached to the spindle in the same manner a s the independent chuck described above. Either two sets of jaws or jaws with reversable tops are supplied with this type of chuck. The large face plate performs the same function a s the small, except that it provides more room to mount fixtures such a s angle plates and vee blocks. The large face plate can also be drilled for the planer type hold- down stops to hold large, irregular pieces that cannot be accommodated in chucks of the conventional type. See pages 25 - 30 for details. (Methods of Holding Work in the Lathe.