View Full Version : Flair nut Seat Cutting

06-25-2005, 08:06 PM
I didn't see the solution in MSC. I need to cut a 37 degree seat for 5/16 flair tubing. Does someone make a piloted seat cutter for this? Is there an easy way to do this?

Actually I need to clean some damaged seats up, I don't really need to cut new ones this time. I have NEVER had a flair fitting leak, but some ham handed person (previous owner) has buggered two and I would like to fix the leaks.

06-25-2005, 09:24 PM
Maybe one of these:

37 degrees is usually aircraft tools. Don't know where else you'd find it.

Or is it the other side, not the tube?

[This message has been edited by Sprocket (edited 06-25-2005).]

06-25-2005, 10:02 PM
<font face="Verdana, Arial" size="2">Originally posted by Sprocket:

Or is it the other side, not the tube?

i think so...

06-25-2005, 10:27 PM
Hey Flyingchips,

I think the tool(s) you want are sold by refrigeration supply houses.

A cup nut screws onto the fitting and a cutting tool with a tee handle lines up in the cup, twist the tool and cut (clean up) the seat.

I don't know of a particlular brand from memory. Most likely Imperial makes one.

A comercial refrigeration shop might be able to help you.

You might be able to rent one from a rental tool place.

06-26-2005, 08:16 AM
If it's 5/16 it's probably not AN stuff. Are you sure it's 37 deg. and not 45? Either way, for both series you can buy copper cone-shaped washers that will fit between the tube flare and the fitting, to seal boogered-up seats.

06-26-2005, 06:38 PM
Where are these copper cone washers found? Sounds like the solution.

06-26-2005, 06:46 PM
I've gotten mine from hardware stores over the years, but here's a link I found with Google:


06-27-2005, 09:20 AM
Earls Performance Products - makers of aluminum 37 degree AN fittings and stainless braided hose - among other things, makes a conical seal for repairing damaged seats.
The conical seal is a soft metal piece formed to match the fitting.
It works on either male or female fittings.

They are size specific so if you're running a #10 fuel line you'll need #10 seals etc.

Installation is simplicity itself.
Fit the conical seal over the male fitting and assemble.
We've used these often and never a problem.

It's not recommended, but the conical seal allows 45 degree fittings to join 37 degree AN fittings with no problems.
We've done this one in oil systems that routinely reach 100#.

Speed shops that carry Earls usually have them and if not you can mail order them.

Earls also has a website.

And fwiw - I've taken a light cut on damaged male fittings to clean them up.
Works fine.

I've also cut a 45 degree chamfer on the 37 degree AN fitting to set up a fuel injection system.
One of those Friday night, "what are we gonna do now" bits before the races....

06-27-2005, 07:47 PM
And if all that doesn't work, look for a JIC #-5 fitting in the hydraulics section of your favorite catalog.