Avoiding Cross-Threading Flare Nuts, Etc

[jim evans]

Trying to start threaded fasteners on stiff tubing without cross-threading (For example, flare nuts on soft copper tubing such as used for gas and water supply lines) has been a lifelong frustration. Since it is hard to know when the parts are exactly in line and the side force applied by the tubing doesn't let you tell by feel if the thread has started properly, there's always the fear it may be cross threaded (and sometimes it is). By the very nature of the place you run into these things it will be a major PIA if you screw up the threads and have to replace the whole thing.

So my question

Is there a secret to lining up these parts so you can be confident they aren't cross-threaded?

jim ___ Have a home upkeep question? Try my help page. It's sort of an alt.home.repair FAQ.

[JSin]

A tick from when I has an old volkwagon (threading steel sparkplugs into a magnezium block) use a piece of softer hose around the end of the nut about 8 in long. Start turning it. The length of hose keeps you from generating enough torque to cross-thread but will allow the proper threading to run right on. You might also lubricate the threads with silicone or other lube so they easily go where they are supposed to rather than cutting.

[JTM]

And then just leave the tubing on the pipe so some future plumber wonders what the heck that was for.

The tubing trick is a good idea for inaccessable locations but for most fingers and a little dexterity will work ok. If things are properly aligned you should be able to start the nut by hand and get several turns before using a wrench. Give the tubing a good pull to make sure the threads are engaged before proceeding. You won't be able to cross thread the nut without a wrench and conversely once the threads are engaged a couple of turns you cannot crossthread them with a wrench.

Regards,

John

[kjpro]

Start them by hand first. Then tighten them with the wrench.

-- kjpro _-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>_-~-_>

( kjpro @ starband . net ) remove spaces to e-mail

Want it done yesterday? Or done right today, to save money tomorrow!!

_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>_>

[meirman]

In alt.home.repair on Fri, 04 Jul 2003 21:41:39 -0500 jim posted:

Until it clicks, or falls forward. That is when your nut is just in front of the start of the thread. I'm sure that is what you mean.

Meirman

If emailing, please let me know whether or not you are posting the same letter.

Change domain to erols.com, if necessary.

[TURTLE]

This is Turtle.

What are you doing giving the trade secrets away like this for free. Now I will loose 3 or 4 jobs this year from other service companys screwing up flare driers and leaking.

TURTLE