stainless nylock nut

did you try antiseize

Try GRAPHITE GREASE. I use it in my hot rig and have good results.

For smaller-sized fasteners; perhaps a shot of an aerosol-based liquid silicone lubricant? This should not affect the properties of the nylon, but without testing one cannot be sure. I am thinking along the idea of inexpensive and quick.

Regards,

Ing. Robert Forbus

Probably not. Even if you put water on the threads, the locking properties would be affected. The question is in what kind of environment will this fastener have to maintain its locking properties (heat, vibration, strain, etc.) and how much of that property are you willing to give up relative to that environment.

The way I look at Nylocks is that their purpose is to prevent the nut from moving on the bolt when heat or vibration change the tension (strain) on the bolt, creating a momentary "loose" condition at the joint. The only torque force would be the vector of the clamping pressure acting on the angle of the threads. Using a fine pitch threaded fastener would decrease that torque. Using antisieze with this set-up should only decrease properties to those of a coarse threaded combination (off the top of my head, seat of the pants, certainly not a calculus inclusive way of thinking).

If you are not comfortable with the Nylock/antisieze idea, a better set-up would be a clinching, deformed, or interfering thread (prevailing torque) nut. With those, you could coat the threads with moly grease and still have a secure joint.

You can get a spray lubricant that is basically teflon suspended in a volatile vehicle that evaporates and leave a dry teflon powder. It is cleaner than graphite but more expensive.

Thread galling is a strange stainless properity the can be over come to a degree of using different stainless grades as this has worked for me in the past and it is common practice where possible to use 304 with 316 etc. As usual, the finished product must adhere to the specifications required so check the details. The Nyloc nut competency is not compromised in this type of use.

Les

Pure and simple, the answer is NO.

All those who are offering you a lubricant, or anti seizing paste of some kind. simply do not know what a Nylock® lock-nut is. and how it works.

You will never get the SPECIFIED (designed ,as you say,) locking properties as they would be with the dry Nylon lock. even as one of the poster correctly said, you wet it with water.

Wangito.

Loctite, will lube & hold.

Use new bolts or studs, you should be using new nuts every time as nyloks are single use. Make sure new or old fasteners are clean, many times the vendors will sell you dirt & chips w/ your nuts.

The different series stainless will help.

I don't remember seeing prevailing torque in stainless, seems like this would promote galling in a big way.

Aircraft hardware is often stainless. They use a clinching nut that has a nose that is slightly extended from the body of the nut and then the extended portion is slightly deformed into an oval shape. There is another type that looks like a regular nut and on three of the flats they indent a small square to deform the threads slightly. Of course for aircraft use, these are one time use and not to be used with antisieze so galling is not an issue. I have used them on motorcycles with antisieze and, upon inspection (naked eye), haven't seen damaged threads. When reassembled, I didn't notice any appreciable difference in torque to run it down. I'm sure intense inspection would show some wear, but for my use I was satisfied. I never had one of those gall, although I have had common (hardware store stuff) stainless hardware gall.

Yes.

1. Do not use and "impact wrench" of any kind to install or remove ever. (When installing, threads will be pulled. When removing, threads will twist inside the nut.)

2. Even if the threads look clean, use a wire brush and clean them. Airborne particles enjoy s/s as a home.

3. Remove the nut slowly. Disassembly at high speed over heats the threads. (see #1)

4. If you are using a 316 grade or lower s/s, follow the rules of torque and subtract 3% when doing installation. Change the size of the bolt to match the reqired torque. Example: if you are using a 3/8 bolt at 30ft pounds, change it to a 7/16 bolt size and torque to 30ft pounds. Avoid pulling the threads....

5. "Always", inspect the bolt and nut before installation. Manufacturing quality is often poor, because tooling is often over used to cut threads. Spend the big dollar and get what you pay for. Spend the low dollar, get what you pay for. The threads must be clean from top to bottom. Purchase only bolts and nuts that are package at the mfg in group of five or less. Bulk in a basket means damage threads.

6. Application: Torque is important here. Depending on what you are securing, the secured will expand and contract. The threads will be pulled during expansion and likewise when the secured contracts, the threads will become lose. "Nylock nut does little good here". During expansion "or heating", the nylock will melt into the bolt. "Into every pore". Contamination means galling.

7. If your application is for cold environment, disassemble in the same environment. Use dry ice to freeze the nylock.

8. Use a normal nut with washer, with a "appropriate" low straight locktite. Locktite that secures with the absents of oxygen, "may or may not be correct"?

9. Keep your bolt as short as possible. Minimal thread showing past the nut.

10. The absents of oxygen, "means rust" no matter the grade of s/s.

11. application, application, application......

Yes, but it's not stainless. Chemk doesn't describe the application, food or chemical can require SS.

No problem promoting your products, please register.

You can use molybdenum disulfide.

Best Regards,

Tadeu

When we assemble stainless parts they have to be free of all lubricants. If there is a tendency to gall we might use some isopropyl alcohol as a lubricant, this quickly evaporates off & leaves no residue so, in your Nylok application, I would have thought that the locking properties would be unaffected.

Also remember: addition of any lubricant will change the torque requirements:

1. The friction factor changes from one application to the next. That is, the friction is at its highest value when the fastener is first tightened. Each additional time the fastener is torqued and loosened, this value gets smaller. Eventually the friction levels out and becomes constant for all following repetitions. Therefore, new fasteners should be tightened and loosened through several cycles before applying final torque. The number of times depends on the lubricant. For all situations where ARP lubricants are used, five cycles are required before final torquing.

2. The lubricant used is the main factor in determining friction, and therefore, the torque for a particular installation. Motor oil is a commonly used lubricant because of it's ready availability. If less friction is desired in order to install the fasteners with less torque, special low friction lubricants are available. With special lubes, the required torque can be reduced as much as 20 to 30 percent. It is important to keep in mind that the reverse is also true. If the torque value has been specified for a particular fastener on the basis of low friction lube, installing the fastener with motor oil will result in insufficient preload; the torque has to be increased to compensate for the extra friction caused by the motor oil.

3. Surface finish is also important. For example, black oxide behaves differently than a polished fastener. It is therefore important to observe the torque recommendations supplied with each fastener.

NOTE: It is possible for even the most expensive of torque wrenches to lose accuracy. We have seen fluctuations of as much as ten (10) foot pounds of torque from wrench to wrench. Please have your torque wrench checked periodically for accuracy.

The application is on a wind generator it is mounted about 300 ft off the ground so I guess it is exposed to a lot of temp. extremes. The bolt in guestion is for mounting a ss vent can to the end of the hub (the end that holds the blades) the housing is fibreglass and the seam has ss nut plates the top 3 holes have a ss bolt screwed inward and a ss Nylock nut on the inside, the problem is the bolt backs out while the nut is installed, we have put locktite (red & Blue) on it but the friction from installing the nut seems to be putting to much friction on the bolt and backing it out.

I like Garthh's idea of locktite on the end threads for applying the nut.

Or maby using a shorter bolt so as much friction heat is not produced.

any thoughts

Thanks Pete

Try using 2 plain nuts & applying the green loktite for assembled fasteners.

Another solution would be to use drilled socket heads & safety wire, deleting the redundant locknuts all together.

You haven't mentioned the size of the bolts, so I assumed 1/4" socketheads [allen]are much easier to drill than hex heads.

Since the cover is fiberglass I can see the problem, over tightening will crack the covers. You might also consider bellville spring washers.

Or tab washers instead of the lock wire, really anything that stops the bolt rotating.

I sounds like you are using the Nylock as a jam nut against the threaded nut-plate. Excellent idea except for the possibility of loosening the bolt due to the friction.

Why not use a regular nut that is drilled for lock-wire. That way you aren't compromising the bolt tightness when running the nut down, you are able to tighten against the nut-plate without having to use EXCESSIVE torque and with the proper wrapping and securing of the lock-wire, prevent any loosening of the jam nut. All this is done on the inside of the hub so it won't be a problem aerodynamically.

I have used Stainless Steel Nylock nuts for over 20 years in marine applications, with sizes ranging from 6-32 to 1/2-13. In the beginning I used to experience a galling problem, especially when using a bolt longer than needed, so that the nut would be tightened over a thread length several times its own depth. I discovered that if I tightened such a nut very slowly, the galling was almost or completely negligible, but if I tightened the nut rapidly using a ratchet wrench or a pneumatic nut runner, the galling became severe. The fast speed of the nut runner produced the worst galling, sometimes effectively welding the nut to the bolt, requiring destructive removal. I use mostly 304 stainless, sometimes 316, and never use a nut runner since I first tried it, with disastrous results.

Nice..

you are using nylock nut for 20 years.

I have a question here.

Is there any need of using plain or spring washer at the time of installing bolt with nut???

Run the Threads through unheated candle wax. It creates enough lube to get it started and threaded smoothly and then allows for heat to get rid of the lil residue left behind. very lil is needed.

We've been having a problem on a smaller scale with stainless screws in stainless thread inserts. One thing I've learnt is that similar stainless materials will gaul. If the bolt & nut are different, one austenitic & one martensitic they do not gaul.