Snap-in screw tip - how was it made?

[nx13688]

I've been asked to do 3D CAD models & drawings for a guitar bridge, and I've run into a feature that I've not seen before. There is an 8-32 thumbscrew with a tip that snaps into the screw and rotates freely. I can see how the tip itself was made, but I'm trying to figure out how the hole for it was made. Obviously, there is a necked-down section within the hole to retain the shaft, but how was that feature made? Is there any kind of standard for a feature like this? Does it have a name?
Thanks for any insight!
Ryan

[fizzissist]

Assuming the tip snaps into the threaded end of the screw...the hole probably has a relief machined near the end of the hole, and the tip would have a snap-ring to retain it. The relief would be machined with a very small boring bar ground to generate a snap ring groove. An undercut on the shaft of the tip, right below the head would support that idea.

Alternatively, and the way I'd do it for simplicity, is to drill the hole in the end of the screw, and take a small ball bearing, place it over the hole, and smack it good with a hammer to peen the end of the hole. That will swage it and give a small lip to act as a retainer. ... That's what I'd do if I just needed one part.

On the tip you'd make a very small sleeve with a slit that will slip over the tip's shaft and allow the tip to go into the screw's hole, but the sleeve will act like a snap ring...or, you could just use a small snap ring.