Rocket CenteringRing

From FreeCAD Documentation
Jump to navigation Jump to search
Other languages:
English • ‎français
Arrow-left.svg Previous: Rocket Bulkhead.svg Bulkhead
Next: Fin Rocket Fin.svg Arrow-right.svg

Rocket CenteringRing.svg Rocket CenteringRing

Menu location
Rocket → Centering Ring
Rocket Workbench
Default shortcut
Introduced in version
See also


A Centering Ring is a solid object used to hold one or more body tubes inside another body tube.

CR with tubes.png



  1. There are several ways to invoke the command:
    • Press the Rocket CenteringRing.svg Centering Ring button.
    • Select the Rocket → Rocket CenteringRing.svg Centering Ring option from the menu.
    • Double click on a Centering Ring object in the model view.
  2. Set options and press OK.



Centering rings, especially those used for low power rocketry, often need a notch to accommodate an engine hook. The Centering Ring tool can generate those for you.

Notched CR.png

Centering ring with an engine hook notch


Rocket Component

These parameters are provided for information and have no effect on the design of the component.

  • DataManufacturer: Manufacturer when known
  • DataPart Number: Manufacturer part number
  • DataDescription: Description of the component
  • DataMaterial: Material when known


These properties are inherited from the Bulkhead, see Bulkhead for more information.

  • DataDiameter: The outer diameter of the bulkhead
  • DataThickness: The thickness, not including any step, of the bulkhead
  • DataStep: True when the bulkhead includes a step, see Bulkhead Options
  • DataStep Diameter: The outer diameter of the step
  • DataStep Thickness: The thickness, not including the bulkhead thickness, of the step
  • DataHoles: True when the the bulkhead has one or more holes, see Bulkhead Options
  • DataHole Diameter: The diameter of the hole
  • DataHole Center: The distance from the center of the hole to the center of the bulkhead
  • DataHole Count: The number of holes applied in a radial pattern around the center of the bulkhead
  • DataHole Offset: Offset from 0 degrees of the first hole

Centering Ring

  • DataCenter Diameter: The diameter of the inner hole
  • DataNotched: True when the center hole includes a notch, see Options
  • DataNotch Height: The notch height
  • DataNotch Width: The notch width


See also: Category:API and FreeCAD Scripting Basics.


Tutorials and Learning

Rocket Workbench Body Tubes, Bulkheads, and Centering Rings Tutorial on YouTube

Arrow-left.svg Previous: Rocket Bulkhead.svg Bulkhead
Next: Fin Rocket Fin.svg Arrow-right.svg