ASME B5.8:2001 pdf download CHUCKS AND CHUCK JAWS
1 scOPE AND PURPOSE
This Standard applies to chucks for use on enginelathes，tool room lathes，turret lathes,and automaticlathes and fit American Standard Spindle Noses ofANSI-B5.9-1967.They may be used on other applica-tions for which they are suitable (see pages 4 and 5of ANSI-B5.9-1967). It is within the scope of thisStandard to establish:
(a) duty classes
(b) standard chuck diameters(c) top jaw interchangeability
(d) mounting interchangeability (USA-StandardSpindle Noses)
(e) draw-bar interchangeability for power chucks(identification code for body，master jaws，topjaws dimensions，where interchangeability of chucksmay be involved
(g) nomenclature
2 CHucK SIZES AND DIAMETERS
The following table gives the approximate chuckbody diameters of each size of standard chuck. Allstandard chucks with two jaws，three jaws，or fourjaws，whether independent,self-centering, or combina-tion type,both wrench-operated and draw-bar operated,shall be made so that the outside diameter of the chuckbody is one of these sizes. The name of each chuckshall be as given in the following table. For example,a chuck,the body ofwhich is 6in. in diameter,shall be known as a 6 in. chuck; one with a body 12in. in diameter shall be known as a 12 in. chuck.
3 SPECIFICATIONS OF CLASS I CHUCKS Class I chucks are medium-duty, wrench-operated chucks with master jaws of the tongue-and-groove type for use on engine lathes and for other applications where the service is not severe. These chucks are provided with master jaws of the dimensions given in Table 1. The tops of the master jaws project above the face of the chucks in all sizes. The mating dimensions of top jaws for these chucks are given in Table 2. Standard three-step reversible top jaws for these chucks may or may not be made so that with the long gripping surface of the top jaws inwardly mounted, the top jaws and the master jaws will both grip a piece of bar stock inserted through the chuck. When the three-step jaws are reversed, the inner ends of top jaws may or may not have gripping surfaces. If they do, the ends of the master jaws project inward beyond the top jaws to provide a definite shoulder on the master jaw for locating any piece that may be gripped by the inner step of the top jaws. These chucks may have two or more jaws and may be of the independent, self-centering or combination type.
4 . SPECIFICATIONs oF CLAss u CHuCKsClass lI chucks are heavy-duty wrench-operated ordraw-bar operated chucks with master jaws of thetongue-and-groove type for use on turret lathes andfor other applications where the service is severe. Thesechucks are of stronger construction than Class I chucks.The wrench-operated chucks may be either hand oper-ated or power operated. The draw-bar operated chucksare actuated by an air cylinder，a hydraulic cylinder,or other means. These chucks may have two or morejaws，and may be of the independent,self-centering,or combination type.
5 BODY DIMENSION AND MASTER JAw
DIMENSIONS OF CLASS ” WRENCH-OPERATED CHUCKs
Table 3 gives body dimensions and master jawdimensions of Class wrench-operated chucks. Thetops of the master jaws of chucks project above theface of chuck bodies with the option of 12 in. and larger to be below the face of body. Mating dimensions of top jaws for these chucks are given in Table 6. Standard three-step reversible top jaws for these chucks may or may not be made so that with the long gripping surface of the top jaws inwardly mounted, the top jaws and the master jaws will both grip a piece of bar stock inserted through the chuck. When the three-step jaws are reversed, the inner ends of the master jaws project inward beyond the top jaws to provide a definite shoulder on the master jaws for locating any piece that may be gripped by the inner step of the top jaws.
6 BODY DIMENSIONS AND MASTER JAW OPERATED CHUCKS Table 4 gives the body dimensions and master jaw dimensions of Class II draw-bar operated chucks. The tops of the master jaws are above the face of the DIMENSIONS OF CLASS II DRAW-BAR chuck bodies for all sizes. Mating dimensions of top jaws for these chucks are given in Table 5.
7 CLASS I AND CLASS II COMPARISON The tongues and grooves of the master jaws of Class I and Class II chucks of the same size are identical. However, the tapped holes MJ-12 of Class II chucks are larger than the corresponding tapped holes of Class I chucks of sizes 6 in. to 15 in. 8 SPECIFICATIONS OF CLASS 111 CHUCKS Class III chucks are heavy-duty wrench-operated or draw-bar operated chucks with master jaws of the
ASME B5.8:2001 pdf download
