Stuck Nylock - Help!

[Ziggy]

When threading a nylock on a 1/2" U-bolt chainplate, it got stuck half way up. I can't tighten it, and can't back it off. I'm sure it's not cross threaded. Any ideas for getting it off? I nutsplitter my only hope? I'd rather not damage the U-bolt

[Steve Pope]

If it is a stainless "Nyloc" then it will most likely have "picked up" meaning that the threads have become locked together by galling the thread. Your only possible solution if that is the case is to carefully use your nut splitter. You will need to run a die nut down the thread to remove any damage, and liberally lubricate with lanocote / kroil or some other propriety lubricant / protectant before running another Nyloc onto the thread.
Good Luck.

[Ziggy]

Originally Posted by Steve Pope

If it is a stainless "Nyloc" then it will most likely have "picked up" meaning that the threads have become locked together by galling the thread.

I don't think it's galling. I can turn the nut through about 45 degrees back and forth. I just won't turn any farther.

[Christian Van H]

You can "help" your nut splitter by first cutting most of the way thru with a tiny cut-off wheel or two on a dremel. I mention this because your nut splitter is going to have a hell of a time with that nut! Then chase with a die. I've had 1/2" nyloks do EXACTLY the same thing on new bolts. Good luck, Chris

[Ziggy]

Cutting a slot with a dremel tool sounds like an excellent approach.

I'm curious how often this problem occurs with nylocks--I'm not sure I want to ever use them again!

[Minggat]

Originally Posted by Ziggy

I don't think it's galling. I can turn the nut through about 45 degrees back and forth. I just won't turn any farther.

You ability to tun it back and forth oe not mean it not gauled,

Some people "outlaw" nylocks on their boats

[Christian Van H]

I would NEVER outlaw them, but I'd be careful of larger sizes. On the mounting bolts for my steering station, I galled one bad. Couldn't stand another, so I have split lock washers on them now... also, any bolt with a head that needs a screwdriver larger than 3/8 is a candidate for a lock washer IMHO...

[Steve Pope]

Stainless to stainless is a problem waiting to happen, normal nut or Nyloc it is always possible for it to happen. I had a French Made rigging screw (Acmo) that after having a rigging firm replace the backstays had picked up (the firm didn't tell me) I just luckily checked the lock nuts and found 1 of then had only a little movement, maybe 45 degrees, the swage on the stay had to be cut off and a new one fitted leaving not a lot of adjustment left on the rigging screw, and a badly damaged LH female thread on the SS bottle. I have since got some bronze bottles threaded to 14mm to replace the SS ones so at least there is no chance of it happening again. I have wondered if the French rigging screws have a different angle to their threads as we have had to cut the female threads to a slightly larger dia than a standard tap (in good condition ) gives to allow them to screw together.

[GordMay]

The most practical way to reduce the risk of galling stainless fasteners is to ensure that the threads are clean and free of grit, and a lubricant (molybdenum disulfide) or anti-seize compound (Lok-Tite 242) is liberally applied to all threads, before tightening SLOWLY (especially /w Nyloks).
The idea is avoid frictionally-generated heat; which encourages galling.

To remove a galled fastener, rapid heating OR cooling (not both) sometimes works.
The application of MILD acids, or penetrating oil (usually acidic) can also free galled threads.
Make sure you clean the acid off as soon as the fasteners are separated, to prevent further acid attack.

[GordMay]

PS: Loc-tite can damage plastics, so do not use Loc-tite with Nylok nuts.

[Christian Van H]

Gords dead on, as usual! You might also try Tef-Gel : TEF-GEL - Ultra safety systems - Home page "2. The function of Tef-Gel in eliminating seizing, galling, and friction welding of stainless steel, inconel, and other nickel alloys.

EXAMPLE:

Tef-Gel applied to both mating surfaces of nuts and bolts or threaded holes and bolts leaves a layer of 40% solid PTFE within the thread interface, which works as friction barrier. Tef-Gel, which contains 0% volatile solvents, will not evaporate, cold flow, or dry out, giving protection many years later when hardware must be dissembled."

I really love this stuff! Yeah, I know... so why dont I marry it?

[Ziggy]

Gord,
Thank you--great tips! Why do I always learn this stuff after getting into trouble?

By the way, as Chris points out, it appears this galling problem is much more frequent with 3/8" and larger nyloks.

[Ziggy]

I got the f***er off, by using a Dremel tool with a cut-off disk to cut two slits in the nut, 180deg apart, and then using a nut splitter to break it. The thread under the nut was damaged, and required re-threading. I coated the thread with tef-gel and used two regular stainless nuts (one as a locknut) in place of the nylok. I'd heve used bronze nuts instead of stainless, but I'm not sure of the load limit. I don't like nyloks anymore, though they may be OK when coated with tef-gel.

[Steve Pope]

Congratulations Ziggy Success at last!!. You shouldn't have to worry about the strength of Bronze nuts, equal or stronger than steel, mind you don't get bronze and brass mixed up.

[Christian Van H]

WhoooHoooo! We live and learn. Tef-Gel is sweet stuff. I've never had ANY problems with anything coated with it. Wish I could say the same for graphite never-seize.... CONGRATS ZIGGY!