Mind you, I have little clue... so I'm just brainstorming, trying to help.

The best I figure is you need to get that spring compressed SAFELY before you do anything. Now the problem is, you have to handle it in order to do so, and that's the part that is scary...

So... step one, how to hande safely...

I'd walk over to it (careful) and take some measurements. Figure out what you can make out of wood or something to "seat" the setup in... so that if it does cut loose, you're ok.

maybe something made with wood and threaded rod... I've got the idea in my head -- a wood frame, with threaded rod so you can adjust it. Then once you have it safe and sound you can wrangle the tool off.

Again, I'm just throwing ideas around -- maybe that'll get somebody else's juices flowing.

Good Luck