NukeMMC
02-03-2014, 08:53 AM
I used these many years ago when I was working in the nuclear business. We couldn't use PTFE tape or paste where it would come in contact with system fluids, so we used these seal nuts instead. They have a PTFE sealing ring that seals the external face of the NPT joint instad of inside, and also act as jam nuts. They are called Tru-Seal nuts and are made by Miller (not the welding folks). I believe Parker distributes them, but McMaster Carr (http://www.mcmaster.com/#pipe-locknuts/=qj6d6u)carries them in zinc plated steel or stainless. They are good to 10,000psi in 7/8" and smaller.:thumbup1:
These also allow you to "clock" your fittings to the desired orientation, like when you are using those DWC nipples on the Cobra or Villager master cylinder, or the CNC reservoirs, both of which use 1/8"NPT, and don't want to risk contaminating brake fluid or are nervous about overtorquing the NPT fitting to get that elbow in just the right angle.
I am also using them on my Heidt's power steering valve (3/8NPT and 1/4NPT) and on my fuel filter and Carter fuel pump (3/8NPT). Maybe overkill, but better spending a few extra bucks than fighting leaks.
http://i682.photobucket.com/albums/vv190/nukemmc/IMG_20140128_090733_348_zps1kx1rxad.jpg
These also allow you to "clock" your fittings to the desired orientation, like when you are using those DWC nipples on the Cobra or Villager master cylinder, or the CNC reservoirs, both of which use 1/8"NPT, and don't want to risk contaminating brake fluid or are nervous about overtorquing the NPT fitting to get that elbow in just the right angle.
I am also using them on my Heidt's power steering valve (3/8NPT and 1/4NPT) and on my fuel filter and Carter fuel pump (3/8NPT). Maybe overkill, but better spending a few extra bucks than fighting leaks.
http://i682.photobucket.com/albums/vv190/nukemmc/IMG_20140128_090733_348_zps1kx1rxad.jpg