Drawings. Class 3A does not provide a plating allowance. Activity; Punchout. The starting thread shall be chamfered and the junction between diameters Ae and De shall be rounded to a value equal to F maximum. The percentages provided are illustrative of what one might expect to see should only be used as a general guide. Four major types of joints are to be considered, as shown below. *Yield strength used to calculate torque values are based on the typical yield.*. The grip gaging length is the distance, measured parallel to the axis of the screw, from the bearing surface of the head to the first complete (full form) thread under the head (see Table 1B). Torque should be set to 1,854 Nm (mean torque) on the torque wrench. Below are guides that show these calculations for a variety of materials, bolts sizes and thread counts over a range of frictional conditions.
xref 0000005054 00000 n The length of the screw shall be measured parallel to the axis of the screw from the plane of the bearing surface under the head to the plane of the flat of the point. Cap screws shall be fabricated from austenitic corrosion resistant steel of types 18-8, AISI 384, or equivalent types, and shall have a minimum tensile strength of 80,000 psi for sizes up to and including 5/8 in and 70,000 psi for sizes larger than 5/8 in.
For screws of nominal lengths longer than those for which LG and LB values are tabulated in Table 1B and for screws over 1 inch in diameter, the maximum grip gaging length LG and the minimum body length LB of the screws shall be determined as follows: All drawings and designs herein have been reviewed and have been determined to meet the requisite specifications contained herein.
CAUTION: Care should be used when applying a formula for torque/tension relationships. 0000011167 00000 n 0000011641 00000 n 2. FHCS: Flat head cap screw. The tabulate LG values are maximum and represent the minimum design grip length of the screw. The data provided should be used as a guide, but actual material strengths and fastener conditions may vary. A torque value will be influenced by the fastening methods and tools used. 20. Flat Head - Alloy Steel . 0
The plane of the point shall be approximately normal to the axis of the screw. We will have a grid of logos, when clicked takes you to their estore website. 0000002789 00000 n 0000001167 00000 n 15. For knurled screws the maximum head diameter shall be measured across the tops of the knurl and the minimum head diameter shall be the diameter of the un-knurled portion, or the diameter across the tops of the knurl for those screws not having an un-knurled portion, just above the radius or chamfer at the bottom edge of the head. 8.8 Grade Bare Steel/Zinc Plated; 12.9 Grade Bare Steel/Zinc Plated; 12.9 Grade Bare Steel FINE Thread ; A2/A4 Stainless Steel; DIN 7991 / ISO 10642 Flat Head Countersunk Socket.
A torque wrench has a “scatter” (tolerance) of ±17% to ±23%. 0000007618 00000 n Designation. The socket shall be concentric with the shank within 1-1/2% of the basic screw diameter, D maximum. See examples below: 6-32 x 3/4 Hexagon Socket Head Cap Screw, Alloy Steel .138 – 32 x .75 Spline Socket Head Cap Screws, Alloy Steel, Cadmium Plated. 0000003096 00000 n See Table 6 for hexagon socket dimensions, and Appendix 1 for gaging of hexagon sockets. Torque is applied to the fastener in an effort to elastically deform the bolt shank.
We must account for this in order not to over-tighten the fastener. 2646 25 Heads may be plain or knurled at the option of the manufacturer unless otherwise specified by the customer. Griping Gaging Length, LG. [Illustration of Tensile: Stress-Strain Relationship] Bolted Joint Design: Mechanical Properties of Steel Fasteners in Service. 2670 0 obj<>stream The only way to determine an exact torque value is by actual application. NOTE: The actual clamp load is dependent on a variety of factors including the material, condition of the fasteners, surface finish, lubrication etc.