ASME B18.6.3:2003 pdf free download

ASME B18.6.3:2003 pdf free download.Machine Screws and Machine Screw Nuts.
Recess wobble gages, gaging procedures, and permissible limits are given in Appendix TV.
2.1.4 Slot. The depth of the slot in slotted head screws shall be measured, parallel to the axis of screw, from the top of the head to the interscction of the bottom of the slot with the head surface or bearing surface.
The width of the slot shall be measured perpendicular to the axis of the screw, from the theoretical intersection of the bottom and one side of the slot, to the theoretical intersection of the bottom and the other side of the slot.
Unless specified by the purchaser, the slot width may be slightly tapered from the bottom to the top, or straight, at the option of the manufacturer.
2.1.5 Feature Positional Tolerances. The positional relationship of the heads and driving provisions of screws with respect to the shanks of screws (formerly defined as eccentricity) shall be as follows.
(a) True Position of Head. The axis of the head shall be located at true position relative to the axis of the screw shank within a tolerance zone having a diameter equivalent to 6% of the specified maximum head diameter, or maximum width across flats of hex and hex washer heads, regardless of feature size.
(b) True Position of Recess. The recess in cross recessed head screws shall be located at true position relative to the axis of the screw shank within a tolerance zone having a diameter equivalent to 12% of the basic screw diameter or 0.030 in., whichever is greater, regardless of feature size.
(c) True Position of Slot. The slot in slotted head screws shall be located at true position relative to the axis of the screw shank within a tolerance zone having a diameter equivalent to 12% of the basic screw diameter or 0.020 in., whichever is greater.
2.1.6 Underhead Fillets. Machine screws shall have a definite underhead fillet large enough to ensure that full fastener strength is achieved. The radius of the fillet under countersunk head screws shall be no greater than 4l of the basic screw diameter. The radius of the fillet under truss heads and number 6 sized pan heads shall be no greater than 25% of the basic screw diameter. The radius of the fillet under all other head styles shall be no greater than 15% of the basic screw diameter.
2.2 Length
2.2.1 Measurement. The nominal length of screw L shall be measured, parallel to the axis of screw, from the extreme point to the plane of the bearing surface for scres’s having perpendicular bearing surface type heads.