Not negative at all. Delrin yes. Wood? C'mon that's funny and not for beginners. Which WE, are usually trying to help here. On a flat faced joint, the delrin is a good option if done carefully. Myself, I'd be extra careful using it against the facing on a brass insert where it didn't bottom against the joint collar. It will and does work but caution should be used. (Beginners remember)
Mr. Hightowers mandrells look great but! If the 5/16x14 and 5/16x18 are not set up to go over a piloted joint. I personally would make a bushing that was bored out except for .100 and thread it, so it could just screw right on to the flat faced mandrell and make it universal to accommodate both styles. Before I try to help someone, I think about what could go wrong, not so much, what will go wrong.
On this forum. I have read this is the way I do it and I've never had a problem so many times that, and I'm sorry. I find it funny. I sought of find it disrespectful and I don't mean to. But, some of you forget about the level of beginners your trying to help.
Will any of you take responsibility if someone screws something up or even worse, gets hurt based of what was advised?
Will AZ, because the individual participated and was advised on their forum. I don't know but I do wonder. Atlas use to sell a set of DVD's. That ended because of safety issues in the methods shown.