Stainless Steel Nuts and Bolts

Use any of the antiseize compounds

Though for SS preferable may be the Nickel based

You can use these sites

http://www.sacskyranch.com/antiseize.htm

http://www.bostik-us.com/Files/Catalogs/NeverSeez_catalog.pdf

or try Loctite 8007, 8008,8009,8013 or Molykote P37 paste are suitable for SS. We are of course more comfortable with the loctites and molykotes, but then again our applications are with a bit of heavy load and temperature condition.

Also ensure the locking since these are also thread lubricants and hence antilocks.

I have been using just a plain old oil of any kind..

Dang, I thought you had found the secret to a new energy source, sorry.

My favorite, even works on salters on snow plow trucks.

https://www.neverseezproductscart.com/shop/product_info.php?pName=bostikbrneverseezbrpure-nickel-specialbrbrush-topbrnsbt8nbr8-oz

Pure Nickel Special Anti Seize
A nickel and graphite based anti-seize compound formulated to protect up to 2400ºF against seizure and galling, galvanic and severe environmental corrosion. Never-Seez® Pure Nickel Special is a superior, high temperature anti-seize and extreme pressure lubricant. It contains flake particles of pure nickel, graphite and other additives in a special grease carrier found to enhance anti-seize performance. This product is recommended for use when applications prohibit the presence of copper, especially when resistance to corrosive acidic and caustic solutions is required. Meets Boeing BAC 5008, Ford ESE-M12A4-A, Garrett Engine Div. PCS5721, GE Aircraft A50TF198 Class A, General Motors 14001899, Pratt & Whitney PWA 36053-1 and is tested to MIL-A-907.

For inside, i use a quick spray of WD40, whether (weather?) that enough for outside I could not say.

You may be "over tightening" them too, which will dramatically increase the "galling", use a torque wrench after first finding out the maximum safe torque.....that alone may be enough.....

Its actually quite amazing how much compression is achieved with quite low torques on most thread sizes and types. Somewhere on the web I am sure that you will find such torque tables for each thread type....

If the torques required is still very high, you may need to think about changing to a larger thread size.......which will not need such a high torque.....but has the stability from the thickness of the bolts.....

Use either locknuts (Nylocs are good) or spring washers to make sure that with the lower torque, it will not undo with vibration.....

Think outside the box!!!

I work for Enerpac at the moment (Hydratight in the past 2 years but we were recently taken over by Enerpac up here) in England.

Have a look on the Hydratight website and particularly their Bolt Up program: http://www.boltup.com/

You have to register but it is free.

From there you shall be able to get loads etc for all different types of flanges/bolt/gaskets/lubricants etc.

A good torque wrench or tensioner would get you the required load to seal the joint.

Also, if you are cutting bolts to free the joint this could be very costly in the long run especially if you are using large diameter and long bolts.

A better option would be to use a nutsplitter: http://www.enerpac.com/en/products/bolting/joint-separation-tools/nc-series-hydraulic-nut-splitters

Hope that all helps.

Kev

I would normally recommend a copper anti-seize but, this is some really messy stuff. An alternative would be either a teflon spray lubricant or a white lithium grease. Both are relatively clean and should prevent galling.

To avoid all the stuff mentioned previously which works but is quite messy, try the special PTFE tapes available - not the white kind, but the gray kind which is specifically for alloys.

I have used brass nuts on boats for this purpose.

In sea water (or even near to sea water) that could be very dangerous as Brass is never intended to be used on boats due to it being a mixture of copper and tin. Mixture being the operative word.....

The sea water atmosphere removes the tin and leaves a very weak and "holey" copper behind that can crumble in your fingers......

Even on fresh water boats is not recommended....

There is another metal, I call Gunmetal (I am not sure if that is the fully correct name), that is a better bet for boat/sea applications....

Nuts made from Naval brass are very good.........62% Cu, 36,75% Zn, 1,25% Sn.

The small percentage of tin prevents (or markedly slows down) the leaching of the zinc from the copper. These are OK providing torque levels are not too high. I have machined several valve spindles and other components from Naval Brass with no problems...........easy to machine as well.

Gunmetal is Standard Admiralty Bronze......88% Cu, 2% Zn, 10% Sn........this is used mainly in marine casting and exhibits excellent corrosion resistance in sea water.

.........a mixture of copper and tin.

Correction Andy, ..........copper and zinc.........you probably meant to put that.

Tin actually prevents the leaching of the zinc from the copper.

You are correct in saying that brass should never be used in marine fittings, some people buy 60/40 or 70/30 brass valves.......that is a definite NO! NO! A very dangerous practice, as you said Andy, particularly in sea water environs.

The most common practice is to use disimilar materials. Brass nuts on steel studs are common on engine exhaust manifolds for this very reason.

Without knowing the environment, it's difficult to endorse thread lubes. In my case I use stainless steel and inconel a lot in building fixtures for use in demanding environments. All my fasteners are stainless and they don't exhibit the problem you described.

I need to specifcy Stainless fasteners because of the enormous magnetic fields that are present. Our fasteners must be lube free because of the high vacuum (torr minus 10) and to prevent outgassing that would contaminate.

Where metal to metal contact occurs, we prevent fusion by spraying the contact surface with alumina but I doubt that's a viable solution of a threaded device.

L.J.

Aluminium bronze nuts would work well with stainless bolts these have a high tensile and would not gall but are expensive. This would avoid using nickle anti seize compound which also gives a tendency to over tighten.

Tensioned bolting is a proven option for a lot of applications. The bearing areas need a minimum clearance for the tensioning tool to seat on at least one surface. Several companies have off the shelf products that improve clamping force and serviceability/cycle time.

CAR_ME.

Seizure results from galling between the mating threads and is more prevalent with cut threads. Seizure is essentially cold welding.

The best solution I've found to prevent galling and seizure of stainless steel threaded fasteners is to mechanically zinc plate the SST nuts. The thin mechanical zinc coating provides both an inexpensive dry lubricant and introduces a dissimilar material between the mating threads without the expense of brass or other non-ferrous nuts.

For years I have used colloidiol graphite suspended in isoproponal alcohol (Neolube) for this and never had a problem. It is relatively inexpensive, and graphite is not considered a hazardous material like some places think nickle is.

If you are concerned that the nut might come off if it is not put on with enough torque, Loctite has thread locking compounds that would also work as anti-galling compounds. They lubricate the threads during installation and harden to prevent the nut from backing off. They come in a range of compounds from some that release with low torque to others that will literally break the bolt before releasing. The right compound might help prevent over torquing of the nut while still providing a good seal, and still assure that the nut can be readily removed in the future.

I had a similar application several years ago. Stainless UNC bolts and Nylock nuts, 5/8" and up. Could not use pastes and such due to contamination (particle issues). Air impacts were causing seizing in the shop. Then I tried to lube with light oil and tighten with a hand ratchet. Still got seizing every time, often before reaching normal torque. Others tightened normally, then would only come partway off and stop turning. If you cannot use pastes, you must not use an all stainless system, even slowly and gently.

David

Lubricants, sadly, alter the normal torque, making it very difficult to judge. Maybe there are even tables around that can give a corrected value for specific lubricants......I believe I read somewhere that the right lubricant can halve the needed toque, but still give the same pressure between the nut and bolt....

When assembling an engine, I clean off any lubricant residues carefully using denatured alcohol.....

Using the same torque with a lubricant could cause serious damage........

Be careful.........

Andy,

You've made a very astute comment about 'lubrication affecting torque'. Unfortunately, there are no tables providing correction factors for the existing lubrication factors. The entire game of trying to determine the proper K factor in order to calculate the required torque is utter folly. It's like telling somebody how the soup is going to taste before you've even put a spoon into your mouth. You can guess, you can consult the oracles, you can read the tea leaves and you can hope but, without checking after the fact, you'll have absolutely no idea!

Here's a link that expands on this. Of particular note is that it points out that torque tool calibration is often of no consequence and actually, quite a useless exercise:

http://www.heviitech.com/Hevii_TorqueDanger.html

I agree completely, the links was also very informative, thanks.

GA from me.

I/we learnt something usefull from you, thanks.

Hey Andy..

For what's it worth, you know the old addage, "the poofs in the puddding"

For Twenty years now, I have practiced using Stainless Steel nuts, over just plain old galanized bolts..

Recently, I was blessed to be able to get back some of our lights, that had held up in the severly corrosive environment of Chicken Houses, Moisture(from the cool cells), dust, Chicken Feathers, and MUCH, MUCH Ammonia, from their excrement!

I am pleased to say, all my parts came loose, just like the day we built the lights.

The galvanized bolts were rusted, (after 18 years), but the stainless steel Nuts cut right through it, and they dissasembled perfectly..

BTW... Campbell Lighting builds TOO good of lights, to last 15-18 years before a socket, or an ignitor, or a ballast needs replacing..

Why can't everyone build products that good???

Donald

PS..

That Fluid Film REALLY is great stuff.. 10 times better than WD-40

When I faced the machine tightening issue, I thought that slow use of a hand ratchet, and bathing the threads in light oil would be sufficient. They were nylocs, so there was a bit of load on the threads all the way down, but they locked up before the nut was even home in some cases. Inside a transformer we cannot have metal particles. We seek to have low magnetic permeability, so stainless and polymer bolts are common. I believe the stainless bolt and bronze nut is optimum for high strength; filled polymer 'bolts' for dielectric and low strength apps.

Hello everyone, I am new to this forum.Thanks to the administrator for making such a good forum. I found this is good forum where I can take part in a discussion about my experience and thoughts. I can share my views and also take advices and suggestions from others. So thank you for allowing me to be a part of this forum.

Fluid-Film, a very "Green" product made from simply lamb's wax, Lanolin..

It's the best anti-seize product I know.. Doesn't evaporate very fast.

You can find it on the net..

Donald

We have used Swagelok's Silver Goop on their range of fittings. Product contains silver and last time we bought it (>10 years ago) was as dear as poison. I note that there are other Goop products on the Swagelok website: http://www.swagelok.com/leak_detectors_lubricants_sealants/Goop_thread_lubricants.htm

Malcolm

I agree with previous post

Zinc plate the ss nuts or use Carbon steel nuts AND ALWAYS use a nickel based antiseize

Hex Bolts, Nuts, Allen Bolts, Carriage Bolts, Allen C.S.K, Machine Screws, Self Tapping Screw, Stud. in a very short span of time these products have been acknowledge as of the highest quality coming out of India.