When in Doubt, Get a Bigger Positioner

If you're unsure which welding positioner to choose, the simplest and safest rule is this: go for a larger machine if your job is anywhere near the upper limits of a smaller one.

Think about your workpiece not just in terms of weight, but also how far it sticks out. A relatively light object mounted far from the centre of rotation creates a large torque, putting far more strain on the machine than the weight alone suggests.

Also, consider welding rotators to mitigate torque.

Understanding Capacity: It’s All About Leverage

Welding positioners aren’t rated only by how much weight they can hold — they’re rated by how much torque they can manage. Torque is a product of weight and distance from the centre, so both factors are critical. This is where charts like our 5-tonne load chart come in.

Let’s break it down with a rule of thumb:

Torque = Weight × (Distance ÷ 2)
(in Newton-metres, assuming weight is in kilograms and distance in metres)

Our positioner load chart tells you the maximum weight it can safely handle at various distances. For example:

• At 500mm from the centre, a balanced load can weigh up to ~3000kg.

• At 2000mm, that safe limit drops to around 600–700kg, depending on how balanced the load is.

To help you quickly estimate this, we’ve analysed the official load chart and created simplified formulas:

• Balanced Load:
  Load (kg) = 114007 / Distance^0.69

• Unbalanced Load:
  Load (kg) = 100844 / Distance^0.70

Plug in the distance in millimetres to get a rough guide to the maximum load. For example, a workpiece mounted 1500mm out from the centre would allow:

• ~840kg if balanced

• ~760kg if unbalanced

This helps you avoid overloading a machine even if the raw weight seems within spec. When unbalanced, the safe limit is significantly lower.