Ever noticed how annoying it can be using a mill with a sprung handle. They are great for not getting hung up on when power feed in operation, but then what are you doing at that end of the machine ?
In my case the spring has too much force for comfortable operation manually. So this calls for 3D printed solution, other materials, methods of construction and overriding safety features are available...
Measure up for the mill, in this case I needed an 8mm thick component to go round a 17mm shaft with a hole for a lanyard so it can be left hanging from the handle. It was pretty quick to print, the jaws have a slight incline so they are easy to insert under the hand wheel washer, the shaft area is opened out to 18mm diameter for some clearance. The spring easily keeps the wedge in place during operation and it's just as easy to remove. Be careful your looped attachment doesn't lock up the hand wheel in one direction when turning, couple of wraps of the string are enough for me.
I have included a link to the STL file, if anyone is interested, just modify it to your requirements, it gives you an easy model to go from.
https://grabcad.com/library/milling-machine-sprung-handle-wedge-1