It would be good if AAC had a "soldering" forum.

This is from my old (30yrs old) Pace ST25. I can't seem to find tips with this hard wire loop out the rear.
Anyone know a part # for this, or if some other tips will work?

 

Depends on the style/method of heating, obtain one of the same dia and try it!

 

The tip is secured with a single side set screw. The wire seems to insert with a smidge of spring retention, perhaps helping to prevent the tip from falling out if the set screw comes loose?

 

Pace - Murray Percival Company

 

I don't think they make it any longer.
The new PS90 irons no longer use tips with that wire loop. The loop does appear to just be a safety thing.
Will seek out if the 2023 PS90 tips will work with my 1989 PS90 iron.