Anyone know the secret to stopping pressed nuts in chassis from seizing?

[Mike_J]

I have been having problems with stainless steel bolts seizing in the stainless nuts that my metal man puts in my chassis.  Real problem to fix.  I use the same truss head 10-32 screws used in the Fender tweeds.  Apparently stainless doesn't like stainless.  Must be something I can use to stop the problem.  Does anyone have a suggestion that would solve this problem?

Thanks
Mike

[sluckey]

I've never heard of such. SS into aluminum (especially in a marine environment) will certainly seize. But I've never had a problem with SS in SS. Too much torque? Maybe use a smaller screwdriver or set your drill/driver clutch to a lower number.

So, how many seizers are you talking about? One? Two? One hundred?

Kep nuts will help.

[Jack_Hester]

If you don't want to use something like NeverSeize (oily and messy), try graphite.  Sometimes the powdered form will work.  But on threads, you may have to make a paste with a very little petroleum jelly.  Use it very sparingly, so that it won't be messy.  That works on most applications, including those where some heat is involved.  The p-jel will ooze out, but the graphite stays behind. 

Sometimes, pencil lead will do the trick, scraping over the threads. 

Dissimilar metals will always oxidize and eventually seize.  We have lots of situations like that at the plant.  Those sometimes require loosening and re-tightening.  Most just get replaced if they ever need to come apart. 

I learned this the first time from my Father, using the pencil lead.  I discovered the powdered graphite, on my own, in later years.  Our mechanical maintenance staff uses NeverSeize almost exclusively. 

Jack

[Mike_J]

I've never heard of such. SS into aluminum (especially in a marine environment) will certainly seize. But I've never had a problem with SS in SS. Too much torque? Maybe use a smaller screwdriver or set your drill/driver clutch to a lower number.

So, how many seizers are you talking about? One? Two? One hundred?

Kep nuts will help.

It has happened twice.  The solution may be what you are saying.  Reduce the torque on the nuts.  I may be pulling them out of the chassis.  I will reduce the torque significantly and see if that solves it.  My metal man put some Teflon lubricant on the nuts which he claims should solve the problem but I am more inclined to believe the problem is with the torque. 

We use stainless screws and nuts all the time in amps without a problem.  Answer may be to use something like Doug came up with for his new chassis.  Those black nuts that wrap around the chassis.  Not much chance of a problem with those.  I need them in 10-32 instead of 10-24 though.

Thanks
Mike

[Mike_J]

If you don't want to use something like NeverSeize (oily and messy), try graphite.  Sometimes the powdered form will work.  But on threads, you may have to make a paste with a very little petroleum jelly.  Use it very sparingly, so that it won't be messy.  That works on most applications, including those where some heat is involved.  The p-jel will ooze out, but the graphite stays behind. 

Sometimes, pencil lead will do the trick, scraping over the threads. 

Dissimilar metals will always oxidize and eventually seize.  We have lots of situations like that at the plant.  Those sometimes require loosening and re-tightening.  Most just get replaced if they ever need to come apart. 

I learned this the first time from my Father, using the pencil lead.  I discovered the powdered graphite, on my own, in later years.  Our mechanical maintenance staff uses NeverSeize almost exclusively. 

Jack

Thanks Jack

Will have to get some NeverSeize.

Thanks
Mike

[Mike_J]

If you don't want to use something like NeverSeize (oily and messy), try graphite.  Sometimes the powdered form will work.  But on threads, you may have to make a paste with a very little petroleum jelly.  Use it very sparingly, so that it won't be messy.  That works on most applications, including those where some heat is involved.  The p-jel will ooze out, but the graphite stays behind. 

Sometimes, pencil lead will do the trick, scraping over the threads. 

Dissimilar metals will always oxidize and eventually seize.  We have lots of situations like that at the plant.  Those sometimes require loosening and re-tightening.  Most just get replaced if they ever need to come apart. 

I learned this the first time from my Father, using the pencil lead.  I discovered the powdered graphite, on my own, in later years.  Our mechanical maintenance staff uses NeverSeize almost exclusively. 

Jack

Never Seez comes in Mariner and Nuclear grade.  Nuclear grade is about three times as much.  Do you know which grade they use in your shop?

Thanks
Mike

[PRR]

Stainless Steel is a complex alloy with complex oxides; also MANY different recipes (slightly stainless, sea-ship stainless, superheated boiler stainless, strong stainless). I could believe different results for different users of different parts. And there's no handy way to know "which" recipe your SS is.

I would favor a grease. Since this isn't engine-cooking, I'd expect many general-duty greases will work, and NAPA brand Lithium spray is my friend. Messy, but you wipe 99% off the thread (and bench and face) and that's all you need. I also use Disk Brake Grease for places I do not want to spray. It starts as a nasty black grease. If you run your brakes red-hot, it degrades to graphite flakes. Again, you want to rub-in then rub-off the excess-- you really just want to seal the surface, not leave a grease-pit situation.

[kagliostro]

You can try also Vaseline streamlined grease

put the screw tread on it before to install

Franco

[Ritchie200]

Got an old candle? Or a slab of parafin canning wax? Rub on threads and you are good to go.  No muss, no fuss, no attracting dirt. Works on many things around the house.  For those of you old enough, that was my hint from Heloise.

Like metals do not play well together.  Many close tolerance stamping dies will use combinations of A2, D2, S7, CPM variants, and carbide to prevent seizing and galling of assembled parts.  Does not matter how hard it is.  If same materials must be used together for some reason, wear parts are typically plasma coated with one of the many coating combinations available depending on use.

Jim

[Jack_Hester]

Never Seez comes in Mariner and Nuclear grade.  Nuclear grade is about three times as much.  Do you know which grade they use in your shop?

Never buy Nuclear grade.  Our Nuke plants use the exact same stuff as us, but it is 'blessed' by a preferred vendor who has all the right paperwork in place to say it's from God.  Then, they put a sticker on it and mark up the price 10x.   

Jack

[Mike_J]

I think I am liking advise from Heloise.  A slab of paraffin wax shouldn't be too hard to find or too expensive.  I have to go to the hardware store today anyway.  Sounds like it should work. 

I put a graphite based product on it to start with and still had it seize although it worked masterfully on pinewood derby cars.  I believe we had a total of seven first place trophies.  Everyone hated to see my kids in the race because they knew they were racing for second place.

Thanks
Mike

[Bill Brown]

"I put a graphite based product on it to start with and still had it seize although it worked masterfully on pinewood derby cars.  I believe we had a total of seven first place trophies.  Everyone hated to see my kids in the race because they knew they were racing for second place."

Ha! My Dad did the same thing 35 years ago.  Brought back a great memory.

Bill

[Mike_J]

Stainless screws and nuts are notorious for sticking.  I believe the term is galling.  Replace the nuts with brass nuts.  The brass is self lubricating.

from another web site  http://www.practicalmachinist.com/vb/general/galling-stainless-steel-machine-screws-171391/
Galling stainless steel machine screws   

Our alleged engineers and designers insist on using 316SS machine screws. There is a constant
 problem with the things galling up and  breaking off. Also, they are to be free of oil (gov specs.). Their solution is"GO GET THE OLD MAN DOWN HERE".I put on my railroad hat and red bandana and say "Where is your big trainwreck, son." These are assemblies that cost
 6 and 7 figures. Don't ask for details. I suggested bronze screws or some other material or
 perhaps some kind of plating. The holes have helicoils, locking helicoils or other inserts. Iwould like to stop the problem instead of being to solution.All ideas will recieve consideration.
 Thank in advance, Old Bill

     

Thanks Old Bill

I will ask my metal guy if he can get brass bolt inserts.  The stainless inserts are pressed into the chassis and are a pain to remove when they gall.  When that happens the inserts release from the chassis and are hard to remove.  I have three chassis with those things installed. 

I like inserts because I can use the Fender tweed type truss bolts that look good and they do not require space through the chassis for installation so they can be spaced pretty much anywhere.  They also carry 200 pounds each if you can keep them from galling.

Think I will use the paraffin wax followed by the Teflon tape treatment with minimal torque with the three amps I already have made that way.  Will ask for brass inserts for any more builds requiring them.

Thanks
Mike

[Mike_J]

Stainless screws and nuts are notorious for sticking.  I believe the term is galling.  Replace the nuts with brass nuts.  The brass is self lubricating.

from another web site  http://www.practicalmachinist.com/vb/general/galling-stainless-steel-machine-screws-171391/
Galling stainless steel machine screws   

Our alleged engineers and designers insist on using 316SS machine screws. There is a constant
 problem with the things galling up and  breaking off. Also, they are to be free of oil (gov specs.). Their solution is"GO GET THE OLD MAN DOWN HERE".I put on my railroad hat and red bandana and say "Where is your big trainwreck, son." These are assemblies that cost
 6 and 7 figures. Don't ask for details. I suggested bronze screws or some other material or
 perhaps some kind of plating. The holes have helicoils, locking helicoils or other inserts. Iwould like to stop the problem instead of being to solution.All ideas will recieve consideration.
 Thank in advance, Old Bill

     

I had another thought.  Don't know where I would find one around here but a chrome shop could nickel plate the stainless couldn't it and then the two wouldn't be touching although that might be insufficient if too much torque is applied.  I don't know.  Anyone think it is worth a try?

Thanks
Mike

[kagliostro]

I was wondering .... are you sure the rivet nuts are SS and not simply Steel ?

---

can you post a link to the Fender tweed type truss bolts I would like to see it ?


K

[G._Hoffman]

Too much torque? Maybe use a smaller screwdriver or set your drill/driver clutch to a lower number.

Less torque, maybe, but you should always use the size driver the screw is designed for, if you ever want to remove the screw.  (A little hyperbole, perhaps, but the point is still valid.) 

Stainless Steel is a complex alloy with complex oxides; also MANY different recipes (slightly stainless, sea-ship stainless, superheated boiler stainless, strong stainless). I could believe different results for different users of different parts. And there's no handy way to know "which" recipe your SS is.

I would favor a grease. Since this isn't engine-cooking, I'd expect many general-duty greases will work, and NAPA brand Lithium spray is my friend. Messy, but you wipe 99% off the thread (and bench and face) and that's all you need. I also use Disk Brake Grease for places I do not want to spray. It starts as a nasty black grease. If you run your brakes red-hot, it degrades to graphite flakes. Again, you want to rub-in then rub-off the excess-- you really just want to seal the surface, not leave a grease-pit situation.

Well, it's pretty easy to know exactly what your screws are made of - buy from a good supplier who carries rated screws.  I always go for 18-8 stainless, but just because it is a good general purpose alloy that is available for just about ever screw type.

The way I have had screw seizing explained to me - by bicycle mechanics, who deal with seized screws all the time - is that similar metals, screwed together, are always at risk of seizing up because their oxides sort of "weld" together.  Certainly, if they are left for much time with no lubricant, it is very likely they will seize.  For grease, I use the same stuff as I use on my bicycle, since I've got it hanging around and it is intended for screws under a wide variety of loads.  But then, I already have that on hand.  Pretty much any lubricant that stays in place will help.  You could also use wax or a weak thread-locker (usually the blue stuff, though Loc-tite Purple is even weaker and would work well too).  Thread locker does, yes, hold the screw in place, but also puts a thin layer of plastic between the two surfaces so they can't seize.  The real trick is just to use SOMETHING.


Gabriel

[Mike_J]

I was wondering .... are you sure the rivet nuts are SS and not simply Steel ?

---

can you post a link to the Fender tweed type truss bolts I would like to see it ?


K

The metal guy that did my rivet nuts said they were SS and I have no reason not to believe him.  I do not remember where I got the 10-32 X 1-1/4" stainless steel truss head screws which are identical to the screws used in the Tweed amps.  If you buy the bolts in the Fender packaging you get four for $12.  I bought the screws I am having the problems with from somewhere that I am sure purchased them from Hillman, 25 for $8 for the same product, just no Fender packaging.  I had the local hardware store order me some that had identical heads but were only 1" long and they ordered them from Hillman. 

Went to the hardware store today and looked in the Hillman catalog today and couldn't find them.  The Fender tweed uses what looks like zinc plated Kips nuts.  Never had a problem with them.  Unfortunately the opening to these chassis face the top of the cabinet so I chose rivet nuts as the solution.  Thinking you can't do better than stainless steel for longevity I thought they were the perfect solution.  The rivets will supposedly support 200 pounds each what could be better?  Problem is if you try to remove them and they are seized or galled it is as if the screw was welded in there.

Thanks
Mike

 

[Mike_J]

Just a thought, since the nuts are not easily replaceable, then switch the metal on the screw.  I believe you can find brass screws at the local big box hardware stores.  I would also consider using torx or allen headed screws.  I would also talk to the counter people at fastenal, or a local bolt company. 

Just an Idea on torquing the screws.  Assuming you have the room, take a cordless drill and use the torque control on the drill, start out low.

This is going to sound absolutely goofy but I like the color scheme and style I have developed for my amps.  I have stolen different ideas from every amp company in existence.  If I use brass it would throw off the color scheme and I have not seen a brass screw that looks as good as the Fender tweed style screw. 

The cordless drill with very low torque idea I think is a key component to not having the problem.  I also ordered some paraffin wax from the hardware store.  The hardware manager was aware of the potential for the problem I am having and thought the paraffin wax would work best so thumbs up for advice from Eloise (one of Ritchie 200's pen names).

Thanks
Mike