Sorry Bob. I overlooked the post, thus didn't see your question.
The tools and inserts were "shop supplies." (Everything was top quality because they didn't like things falling apart.) Stolen is the first thing that comes to many minds when you say shop supplies, but they were very liberal with our use of shop supplies for personal use: Provided that it was for personal use, we could help ourselves to whatever because the money collected by the customer's shop supplies charge, exceeded the total useage of shop supplies.
I would think that Kent Industries or CRLawerence would be the source. The problem is that neither one of them are very retail-sale frenindly.
A threaded-set rivet tool would work well too, but I don't think they have the same @$$bone as this insert.