M3 bolt locknut with handle (15mm diameter)

I needed a handle for a locknut M3 bolt to easily Z level one of my printers and I designed this quickly to do that job. Works fine for me. Outside diameter for the handle is ~15mm for my coarse fingers (works fine also with normal fingers). Insert a M3 nut into the hole, then screw in the M3 bolt, then insert the second M3 nut in the M3 bolt from the downside of the base and tighten it, there is no hole for the M3 nut in the downside to allow an easy tightening. Press/insert the top part (optio