On Tue, Jun 6, 2017 at 3:00 PM, John Finlayson <john_finlayson at telus.net> wrote: > The switch has 1/8 x 27 NPTF pipe threads. NPTF means it's a tapered pipe thread. Assuming everything is otherwise in good nick, it shouldn't need any sealant. Jeff Scarbrough Corrosion Acres, Ga.