Wormdrive gearboxes can be hollow shaft or solid shaft, so the approach to attaching levers is different.

For solid shaft gearboxes that are keywayed @noorbeast suggests the easiest way to attach a lever is to grab the correct sized and length Mild Steel, Black Oxide Plating Rigid Couplings, which have the keyway and grub screws, and just weld the lever on the end: http://www.xsimulator.net/community/threads/using-chinese-actuators.7304/page-3#post-86033




Another option for solid shaft motors are these bolt on flanges: https://www.robotshop.com/nl/en/14mm-set-screw-key-steel-hub.html

As @Nick Moxley explains with hollow shaft motors you can use the correct sized threaded rod through the hollow shaft and weld nuts to it to secure the levers: http://www.xsimulator.net/community/threads/using-chinese-actuators.7304/page-2#post-85902