Celebrating Over 60 Years...
As the World Leader in Tool Systems & Technology for the
Aerospace,
Military and Telecommunications Industries.
Products |
Torque Conversion FormulasTorque is a standard term that is comprised of “distance and force”. Since the force is applied to a threaded component in a circular motion, the distance applies to the radius (center of the torque wrench drive to a designated point on the torque wrench handle). In the case of wire harness applications, it is usually expressed in INCH-POUNDS, NEWTON-METERS, or KILOGRAM-CENTIMETERS. When extensions such as a crowfoot, or strap wrench is added to a torque wrench, it changes the distance (radius), so a mathematical formula is used to determine the correct torque readings on the torque wrench to compensate for the added length. We have included the following formulas for your convenience.
When an adapter or extension is used on a torque wrench it increases the torque range of the wrench. The formulae for computing torque when using an adapter or extension is explained below. A = (Length) Distance from center of torque wrench square drive to center of the puller’s hand grip. B = Distance from center of torque wrench square drive to center of drive at end of extension. C = (Torque) Torque wrench setting. D = Torque desired at drive on end of extension. P = (Force) Pull applied. To determine torque wrench setting: C = (D*A) / (A+B) NOTE: After computing “C” and setting wrench to computation, measure and mark “A” where pull is applied. It is recommended that the axis of the extension always be used in line with axis of the torque wrench as shown above.
Should it be necessary, due to obstructions, to have an angle between the two axes, then the above formula is modified as follows. Due to increasing rounding errors, keep the angle as small as possible. A, B, C, D, & P are the same as above. E = Effective moment arm of the extension. Ø = Angle between extension axis and torque wrench axis. E = (B)(COS Ø) Therefore: C = (D*A) / (A+(B*COS Ø)) When Ø = 0, COS Ø = 1, then equation is reduced to C = (D*A) / (A+B) When Ø = 90°, COS Ø = 0 then C = D (Regardless of the length B)
TORQUE CONVERSION CHARTSThese torque conversion charts were calculated for the BT-ST-300D Digital Torque Tool. If any other torque tool or instrument is used, calculate the torque conversion by using the mathematical formula above.
FOR OUR OLDER TORQUE WRENCHES
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
TORQUE CONVERSION CHARTFor BT-BS-609 and 610 Series used with BT-ST-751 & BT-ST-701 (older models) |
|||||||||
Diameter of |
DESIRED TORQUE VALUE (in-lbs) (“D”) |
||||||||
| 40 | 60 | 80 | 100 | 120 | 140 | 160 | 180 | 200 | |
| .50 | 36 | 53 | 70 | 88 | 105 | - | - | - | - |
| .75 | 35 | 52 | 69 | 87 | 104 | 122 | - | - | - |
| 1.00 | 34 | 51 | 68 | 85 | 102 | 120 | 135 | - | - |
| 1.50 | 33 | 50 | 67 | 83 | 100 | 117 | 133 | 150 | - |
| 1.75 | 33 | 49 | 66 | 82 | 99 | 115 | 132 | 148 | 164 |
| 2.00 | 33 | 49 | 65 | 81 | 97 | 114 | 130 | 146 | 162 |
| 2.25 | 32 | 48 | 65 | 80 | 96 | 112 | 128 | 144 | 160 |
| 2.50 | 32 | 48 | 62 | 79 | 95 | 111 | 127 | 143 | 158 |
TORQUE READING ON INSTRUMENT (“C”) |
|||||||||
TORQUE CONVERSION CHARTFor BT-BS-611 and 618 Series used with BT-ST-751 & BT-ST-701 (older models) |
|||||||||
| Diameter of Part Being Tightened |
DESIRED TORQUE VALUE (in-lbs) (“D”) |
||||||||
| 40 | 60 | 80 | 100 | 120 | 140 | 160 | 180 | 200 | |
| .50 | 33 | 49 | 65 | 82 | 99 | - | - | - | - |
| .75 | 32 | 48 | 64 | 81 | 97 | 113 | - | - | - |
| 1.00 | 32 | 48 | 64 | 80 | 96 | 112 | 128 | - | - |
| 1.50 | 31 | 47 | 62 | 78 | 93 | 109 | 125 | 140 | - |
| 1.75 | 31 | 46 | 62 | 77 | 92 | 108 | 123 | 139 | 154 |
| 2.00 | 30 | 46 | 61 | 76 | 91 | 107 | 122 | 137 | 152 |
| 2.25 | 30 | 45 | 60 | 75 | 90 | 105 | 120 | 135 | 150 |
| 2.50 | 30 | 45 | 59 | 74 | 89 | 104 | 119 | 134 | 149 |
| 2.75 | 29 | 44 | 59 | 74 | 88 | 103 | 118 | 132 | 147 |
| 3.00 | 29 | 44 | 58 | 73 | 87 | 102 | 116 | 131 | 145 |
| 3.25 | 29 | 43 | 58 | 72 | 86 | 101 | 115 | 129 | 143 |
| 3.50 | 28 | 43 | 57 | 71 | 85 | 100 | 114 | 128 | 142 |
| 3.75 | 28 | 42 | 56 | 70 | 84 | 99 | 113 | 127 | 140 |
| 4.00 | 28 | 42 | 56 | 70 | 84 | 98 | 111 | 125 | 139 |
TORQUE READING ON INSTRUMENT (“C”) |
|||||||||