I'm designing a 5 axis CNC, and preloading my lead screws has never been an issue for me, but for the first time, I find myself needing to preload a worm gear. How is this done, and what's the best way to do it? Thanks.


For worm gears, the most common method to reduce backlash is by forcing the worm screw tightly against the gear. Many manual rotary tables used on milling machines have this adjustment.

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  • $\begingroup$ that doesn't seem like it would take up all the lash though... only increase friction... $\endgroup$ – Jedi Engineer Nov 30 '16 at 13:35
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    $\begingroup$ as long as the worm can not bottom out on the roots of the gear teeth, the only contact points should be on opposing faces of each teeth. This wedging action can remove backlash as both sides of each tooth will be in contact at the same time. It will also significantly increase friction. $\endgroup$ – Netduke Nov 30 '16 at 14:49

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