Slotted drilled fillister head machine screw dimensions are shown in the following chart according to ASME B18.6.3 standard.
The fillister head has a rounded top surface, cylindrical sides, and a flat bearing surface.
Some important notes from the ASME B18.6.3:
- Thread dimensions for the No.0000, No.000 and No.00 sizes are also included in the standard.
- The general data about the head height, bearing surface, gaging of recess, slot, length, tolerance on length, length of thread, points, finish, workmanship and designation of machine screws are given in the standard.
Note 1: Dimensions in this calculator are in inches.
Note 2: 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 40% 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.
Note 3: A slight rounding of the edges at periphery of head shall be permissible provided the diameter of the bearing circle is equal to no less than 90% of the specified minimum head diameter.
Note 4: Drilled hole shall be approximately perpendicular to the axis of slot and may be permitted to break through bottom of the slot. Edges of the hole shall be free from burrs.