IH 19985R1 tube nut, what kind of flare?

(quoted from post at 10:15:50 05/20/19) I'm rebuilding a Marvel Schebler carb for an IH 444. Included in the kit is a new elbow with integrated filter screen.

Looks like this one:

https://imgur.com/abLurpc

My Dad took that off his tractor years ago and butchered up the fuel connection with some aftermarket fittings.

If I want to use the replacement elbow, I noticed it's not a standard inverted flare fitting.

From my research, I found that I need an IH tube nut part number 19985R1, looks like this:

https://imgur.com/IgQJymR

I have a tube flaring kit, but this tube nut looks rather special. Is the tube supposed to receive a bubble flare, or is there supposed to be a sealing o-ring or washer used with this setup? Some kind of special flare or flange on the end of the tube?

Click to expand...

(quoted from post at 08:48:36 05/20/19)

(quoted from post at 10:15:50 05/20/19) I'm rebuilding a Marvel Schebler carb for an IH 444. Included in the kit is a new elbow with integrated filter screen.

Looks like this one:

https://imgur.com/abLurpc

My Dad took that off his tractor years ago and butchered up the fuel connection with some aftermarket fittings.

If I want to use the replacement elbow, I noticed it's not a standard inverted flare fitting.

From my research, I found that I need an IH tube nut part number 19985R1, looks like this:

https://imgur.com/IgQJymR

I have a tube flaring kit, but this tube nut looks rather special. Is the tube supposed to receive a bubble flare, or is there supposed to be a sealing o-ring or washer used with this setup? Some kind of special flare or flange on the end of the tube?

Click to expand...

NO flare at all is needed.

The nut is made with a compression sleeve "ferrule" at it's end.

When you tighten the nut the first time, the ferrule gets squashed onto the tube, and breaks free of the nut at the "score line" between the nut and ferrule.

Next time it's removed, the nut will turn freely, and the ferrule will remain crimped to the fuel line.

Click to expand...

(quoted from post at 11:06:25 05/20/19) That nut makes for a good connection. Just be sure to push the tube fully into fitting and hold it
in while tightening the nut or it may walk off the end. For a few years IH used that nut with a
teflon insert in the ferrule and they really sealed good , even on imperfect lines but now days
that is a thing of the past.

Click to expand...