1. Inventory the fill
Note the outer diameter and weight per metre of every cable and hose. Add the diameters of the thickest layer that must lie side by side; that is your minimum inner width. The thickest cable sets the minimum inner height.
2. Add 10 to 20% clearance
Cables must be able to move inside the chain. Allow at least 10% clearance in height and width, and 20% when the chain moves fast or sits outdoors in the sun.
3. Determine the bend radius
The chain's bend radius must exceed the permitted bend radius of the most sensitive cable. Rule of thumb: 7.5 × cable diameter for static applications, 10 × for moving ones. Fibre optics often require 15 ×.
4. Calculate the chain length
Chain length = half the travel + π × bend radius + an allowance for the connection points. Round up to whole links; we do that automatically on a quote.
5. Choose the version
Open crossbars for clean environments and good cooling, closed covers for swarf, dust or splash water. Do not forget end connectors and separators — without those two a chain is not complete.