The insert is loose, that's the reason it floats. The spring is there to keep the insert from falling inside the lug casing when the rod is unscrewed. :)

Ludwig eventually used a plastic 'wedge' to keep the insert in place, not sure what anyone else is doing.

Bermuda

Now, it would be quite retro to use springs rather than plastic to retain swivel nuts in lugs. Plastic bits are almost as reliable as springs; however, springs allowed for a bit of variance in drillings (as machinery was quite a bit more crude than the machinery of today) moreso than today. As I say- modern manufacturing methods allow for consistently good or consistently crappy stuff.

Nobody wants to hear that I had to have vintage stuff redone (as far as edges and beds) before it was vintage and just plain "old" to make it easy to play... Plastic retainers show that manufacturing methods have advanced.

My '79 Tama Imperialstars have a plastic wedge.... long before Ludwig started...

I recently had the opportunity to look inside of some DW lugs from a high-end snare and I was surprised to see black plastic inserts instead of quality steel springs. Plastic parts, in combination with metal, to me represents built-in obsolescence.

JR is right, mediocre is the new excellent.

John

Everyone has gone the plastic "wedge" route. The reason? Springs tend to rattle, even when little bits of foam are stuffed into the casing before fitting the springs. Rattling may be ok for live work, but if you're recording......its a big no-no generally.

My guess plastic is cheaper nowadays too. Either injection molded or die cut from a sheet...

And, some of the high priced mediocre stuff is a small step above junk.