by DCASonex » Thu Feb 10, 2022 9:19 am
I made up the oops fitting tools. Other users have added customized step drills to the kit which I keep here. PM me with your shipping address and include about $8 for the Priority Mail cost when returning the kit.
Most tanks seem to have a large enough boss on the inside that the length of the standard fittings is marginal. Use of a thinner flat washer on the outside helps with that, but if you do not get the inside smoothed off parallel to the outside surface, using O-rings on both sides adds a bit of alignment tolerance.
Only the inside O-ring makes a seal even if you use both. Also the flat washer on the outside eliminates the tendency of the O-ring to bunch up and be forced out to the side of the nut as it is tightened. (use the flats on the end of the fittings to keep them from rotating as the nuts are tightened so as to prevent displacement of the inside O-rings. I undercut both the fittings and the nuts slightly on lathe to make recesses to help retain the )-rings, but most folks have not found that necessary.
David A.