# Improvised Torque Wrench

If you don't have a torque wrench available - or if you want to check the readings of the one you have - it is easy to improvise by using a standard wrench and a scale as indicated in the figure above.

The moment - or torque - can be calculated

* T = F a (1) *

* where *

* T = moment or torque (Nm, lb _{f} ft) *

* F = applied force (N, lb _{f} ) *

* a = length of the wrench (m, ft) *

** Note! ** - Most scales in the SI unit system measures weight - force due to the acceleration of gravity - in * kg *.

- the difference between mass and weight .

The reading from the scale can be converted to * N * by using

* F = m g *

* where *

* m = reading of the scale (kg, lb _{f} ) *

* g = acceleration of gravity (9.81 m/s ^{2}, 32.17 ft/s^{2}) *

### Example - Measuring Torque with a standard Wrench and a Luggage Scale - readings in kg

The reading of the scale at the end of the wrench is * 10 kg * . The length of the wrench is * 0.3 m * . The moment exerted can be calculated

* T = (10 kg) (9.81 m/s ^{2}) (0.3 m) *

* = 29.4 Nm *

### Example - Measuring Torque with a standard Wrench and a Luggage Scale - readings in lb_{f}

The reading of the scale at the end of the wrench is * 20 lb _{f} * . The length of the wrench is 6

*in*. The moment exerted can be calculated

* T = (20 lb _{f} ) (6 in) *

* = 120 in lb _{f} *

* = 10 lb _{f} ft *

### " * Luggage Weight - Wrench * " Online Torque Calculator

### Scale Wrench Torque Diagram - SI units

Download and print Scale Wrench Torque Diagram

#### Example - Torque Settings for a Cylinder Head

The torque settings for a cylinder head in a car engine are specified to * 30 Nm. *

According to the diagram above with a wrench with length * 0.2 m * - the scale readings should be approximately

* 14 kg *

### Scale Wrench Torque Diagram - Imperial units

## Related Topics

### • Fasteners

Bolts, nuts and threaded rods - torque, tension and loads.

### • Mechanics

The relationships between forces, acceleration, displacement, vectors, motion, momentum, energy of objects and more.

## Related Documents

### Angular Motion - Power and Torque

Angular velocity and acceleration vs. power and torque.

### Bolt Torque Calculator

Calculate required bolt torque.

### Car - Required Power and Torque

Power, torque, efficiency and wheel force acting on a car.

### Disk Brakes - Torque and Force

Forces and torque activated with disk brakes.

### Electric Motors - IEC and NEMA Standard Torques

IEC and NEMA torque classifications of electrical motors.

### Electric Motors - Torque vs. Power and Speed

Electric motor output power and torque vs. rotation speed.

### Gear Reducing Formulas

Output torque, speed and horsepower with gears.

### Levers

Use levers to magnify forces.

### Lifting Wheels

Loads and effort force with lifting wheels.

### Metric Bolts - Tightening Torques

Recommended thightening torque metric bolts.

### Piston Engines - Displacement

Calculate piston engine displacement.

### Reduced Torque with Lubricated Bolts

Lubrication effect on bolt tension and torque.

### Screw Jack - Effort Force vs. Load

Screw jacks and effort forces.

### Shafts Torsion

The torsion of solid or hollow shafts - Polar Moment of Inertia of Area.

### Torque - Work done and Power Transmitted

The work done and power transmitted by a constant torque.

### Torque or Moment of Force - Online Converter

Torque or moment - the tendency of a force to rotate an object.

### US Bolts - Tightening Torques

Recommended bolt torques.

### Whitworth Bolt Torques

Torque specifications Whitworth bolts.