Calculate the root circle, tip circle, and pitch circle diameter of the roller chain coupling teeth

Thread Content

This post was last edited by B0SS on 2017-11-5 at 10:09. Marking method for roller chain couplings: The chain code 08A corresponds to what we commonly refer to as a 4-inch sprocket; by the same logic, 16A corresponds to a 1-inch sprocket. It actually refers to the pitch P, with inches being the unit used to express pitch. 1 inch = 25.4 mm; p = 25.4 × chain number / 16. For pitch 08A, p = 25.4 × 8 / 16 = 12.7 mm. The diameters of the root circle, tip circle, and pitch circle of a roller chain coupling are as follows: (1) Pitch circle diameter: d = p / sin(π/z) = 152 mm. (2) Tip circle diameter (for three-arced – straight tooth profile): da = (p × (0.54 + 1.0 / tan(π/z))) = 161.1 mm. (3) Maximum tip circle diameter (for other tooth profiles): damax = d + 1.25 × p – d1 = 163.9 mm. (4) Minimum tip circle diameter (for other tooth profiles): damin = d + (1 – 1.6/z) × p – d1 = 157.9 mm. (5) Root circle diameter: df = (d – d1) = 140.1 mm