ASME B18.6.7M:1999 pdf download METRIC MACHINE SCREWS
1.1 Scope
1.1.1 This Standard covers the complete generaland dimensional data for metric fat countersunk. ovalcountersunk and pan slotted and recessed head machinescrews,and mctric hex and hex flange head machinescrews recognized as standard. Also included are appen-dices that provide specifications and instructions forprotrusion gaging of flat countersunk head screws.across-corners gaging of hex head screws, and penetra-tion gaging and wobble gaging of recessed head screws,and clearance hole recommendations.
1.1.2 The inclusion of dimensional data in thisStandard is not intended to imply that all of the productsdescribed are stock production sizes. Consumers shouldconsult with manufacturers conceming the availabilityof products，The recommended diameter-length combi-nations applicable to metric machine screws are shownin Table t7.
1.2 Comparison With ISO Standards
1.2.1 The dimensions for flat countersunk, ovaicountersunk. pan. and hex head machine screws aspresented in this Standard have been coordinated tothe extent possible with ISO standards. Where applicable, the comparable ISO standard is referenced in thefootnotes to the dimensional tables for the respectivescrew products. Except for the recessed flat countersunkheads, the dimensional differences between machincscrews covered in this Standard and those in ISOstandards are very few and relatively minor. Nonewill affcct the functional interchangcability of screwsmanufactured to the requirements of either. For recessedflat countersunk head screws. the head envelopes areidentical in both standards. Onc ISO standard incorporates shallower recesses without a shoulder and anotherISO standard.identical to this ASME Standard, is beingdrafted.However. heat-treated products covered by thisdocument feature a short shoulder under the head (withan attendant increase in the minimum grip length) andrecess depths consistent with other head styles.
1.2.2 Hex flange head screws and screws implement-ing the Type lll recess are not, as of this writing.covered by ISO standards.
1.2.3 The Types I and IA cross-recesses documentedin this Standard are designated Types H and Z, respectively,in corresponding ISO standards.
1.2.4 Nominal screw lengths of 12-mm and 14-mmare recognized as ISO standard leneths. The 13-mmlength shown in Table 17 is not.
1.3 Head Types
The head types covered by this Standard includethose commonly recognized as being applicable tometric machine screws and are listed and described asfollows:
1.3.1 Flat Countersunk Head, The fat count-ersunk head shall have a fat top surface and a conicalbearing surface with a head angle of 90 deg to 92deg. Dimensions are given in Tables 2 through 5.
1.3.2 Oval Countersunk Head, The oval countersunk head shall have a rounded top surface and aconical bearing surface with a head angle of 90 degto 92 deg. Dimensions are given in Tables 6 through 9
1.3.3 Pan Head. The slotted pan head shall havea flat top surface rounding into cylindrical sides anda fat bearing surface. The recessed pan head shallhave a rounded top surface blending into cylindricalsides and a flat bearing surface. Dimensions are givenin Tables 10 through 13.
1.3.4 Hex Head.The hex head shall have a fator indented top surface, six flat sides, and a flat bearingsurface. Dimensions are given in Table 14.
1.3.5 Hex Flange Head. The hex fiange head shallhave an indented top surface and six flat sidcs formedintegrally with a frustroconical or slightly rounded(convex) flange that projects beyond the sides andprovides a fat bearing surface. Dimensions are givenin Table 15.
ASME B18.6.7M:1999 pdf download
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