Same results can usually be obtained by inserting, at times with some effort required, maybe light tapping with a hammer, any item has an outside diameter smaller than the threaded diameter of the hole- drill bit, screw driver, punch, etc. If necessary, the threads can be chased with the appropriate sized tap. By the way, the inside threads of the plug and the threads on the zinc often need cleaned or chased and can also be done with the appropriate sized tap or die. Most, if not all, threads on heat exchangers used in USA boats are SAE threads, not metric. I've had opportunities to have to replace zincs in heat exchangers in which the threads on the heat exchanger were worn or corroded, making the "right" size plug not fit. Switching to the closest, up-sized metric plug would often work, though ultimately the fitting or the heat exchanger would have to be replaced. Rudy and Jill Lake Worth, Fl Briney Bug- a 34 foot sail-assisted trawler 850-832-7748 -------------------------------------------- On Mon, 2/29/16, Tom Yahoo via Trawlers-and-Trawlering <trawlers@lists.trawlering.com> wrote: Subject: T&T: Heat exchanger corrosion and stuck zinc To: trawlers@lists.trawlering.com Date: Monday, February 29, 2016, 7:51 AM A few years ago I shared an idea given to me by an old salt now deceased. I have a tool made from a brass pencil zinc connector with the outer threads ground off. When I change a zinc and the end detaches before the zinc comes out I just attach the tool and wiggle the zinc out. Worked every time. Tom Egan Sent from my iPad _______________________________________________ http://lists.trawlering.com/mailman/listinfo/trawlers_lists.trawlering.com To unsubscribe or modify your subscription options (get password, change email address, etc) go to: http://lists.trawlering.com/mailman/listinfo/trawlers_lists.trawlering.com Trawlers & Trawlering and T&T are trademarks of Water World Productions. Unauthorized use is prohibited.