I designed this clamping lead screw control knob to be able to manually raise and lower my X-axis gantry. A plain version is also available. It's especially useful if you upgrade your Ender 3 with a dual-z.
Find my Scuddy Drones Dual Z Upgrade for the Ender 3 here:
Supports are not really needed. Use a M3 lock nut and M3x14mm screw to secure the knob to your 8mm OD lead screw.