ASME B18.6.5M:2000 pdf download

ASME B18.6.5M:2000 pdf download.METRIC THREAD-FORMING AND THREAD-CUTTING TAPPING SCREWS
1 INTRODUCTORY NOTES
1.1 Scope 1.1.1 This Standard covers the complete general, dimensional, and performance requirements for the vari- ous types of slotted and recessed head metric tapping screws recognized as standard. Also included are appen- dices that provide specifications and instructions for protrusion gaging of flat countersunk head screws, across-comers gaging of hex head screws, and penetra- tion and wobble gaging of recessed head screws. The appendices in this Standard also provide clearance hole size and approximate installation hole size recommenda- tions. 1.1.2 The inclusion of dimensional data in this Standard is not intended to imply that all of the products described are stock production sizes. Consumers should consult with manufacturers conceming the availability of products. The recommended diameter- -length combi- nations applicable to metric tapping screws are shown n Table 22.
1.2 Comparison With ISO Standards
1.2.1 The dimensions for fAat countersunk, oval countersunk, pan, hex fange, and hex head tapping screws as countersunk, pan, and hex head tapping screws as presented in this Standard have been coordinated to the extent possible with International Organization for Standardization (ISO) standards. Where applicable, the comparable ISO standard is referenced in the footnotes to the dimensional tables for the respective screw products. Except for the recessed fat countersunk heads, the dimensional differences between tapping screws covered in this Standard and those in IsO standards are very few and relatively minor, and none will affect the functional interchangeability of screws manufactured to the requirements of either. For recessed flat count- ersunk head screws the head envelopes are identical in both standards; however, Types D, F, and T screws covered by this document feature a short shoulder under the head (with an attendant increase in the minimum grip length) and recess depths that are consistent with those in screws of other head styles and thread types. 1.2.2 Screws incorporating the Type II square recess, and thread-cuting tapping screws conforming to Types BF, BT, D, F, and T are not, as of this wring, covered by ISO standards. 1.2.3 Other differences exist in tne designation of tapping screws covered by ISO standards and those covered by this document. For example, point Types AB and B in this Standard are designated Types C and F, respectively, by ISO. 1.2.4 Types 1 and IA cross recesses documented in this Standard are designated Types H and Z, respec- tively, in corresponding ISO standards. 1.2.5 Several nominal length differences exist.
1.3 Head Types
The head types covered by this Standard include those commonly recognized as being applicable to metric tapping screws and are listed and described as follows: 1.3.1 Flat Countersunk Head. The fat count- ersunk head shall have a fat top surface and a conical bearing surface with a head angle of 90 to 92 deg. Dimensions are given in Tables 8 through 11. 1.3.2 Oval Countersunk Head. The oval count- ersunk head shall have a rounded top surface and a conical bearing surface with a head angle of 90 to 92 deg. Dimensions are given in Tables 12 through 15. 1.3.3 Pan Head. The slotted pan head shall have a fAlat top surface rounding into cylindrical sides and a fat bearing surface. The recessed pan head shall have a rounded top surface blending into cylindrical sides and a fAat bearing surface. Dimensions are docu- mented in Tables 16 through 19.
1.4 Screw Types and Application
Screws covered by this Standard include screws of both the thread-forming and thread-cutting varieties. The type designations, descriptions, and applications are as follows: 1.4.1 Thread-Forming Tapping Screws. Thread forming tapping screws are generally for application in materials where large intemal stresses are permissible or desirable, to increase resistance to loosening. They shall be of the following types: 1.4.1.1 Type AB. Type AB tapping screws shall have spaced threads and gimlet points. They are primar- ily intended for use in thin metal, resin impregnated plywood, and asbestos compositions. Dimensions are given in Table 5. 1.4.1.2 Type B. Type B tapping screws shall have spaced threads, with the same pitches as Type AB，and blunt points with tapered entering threads having unfinished crests. They are intended for use in such materials as thin metal, nonferrous castings, resin impregnated plywood, certain resilient plastics, and asbestos compositions. Dimensions are given in Table 5.