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Author Topic:   Self welding stainless bolts??????
BOB KEMMLER JR posted 10-23-2002 08:20 AM ET (US)   Profile for BOB KEMMLER JR  
While working on my project,i was installing the jackplate with 1/2"-13 bolts,as i was tightening the bolts they just seem to lock up,so i tried to back them off,nada was'nt happening.So now i need to cut,torch,or grind them off since they are only3/4 of the way tight.Any easy suggestions(serious only please)i was told that i should have used a anti-seize on them,but in all my wrenching days,i have never had this happen.The bolts were brand new with no signs of damaged threads at all,so im really puzzled???HELP!!
JohnAz posted 10-23-2002 08:41 AM ET (US)     Profile for JohnAz  Send Email to JohnAz     
Hapens all the time with stainless called "gauling" ,,use anti seize, and if you are worried about vibrating loose, use "Nylock nuts"
bdb posted 10-23-2002 09:26 AM ET (US)     Profile for bdb  Send Email to bdb     
Exact same thing happened to me, doing the exact same thing (installing a jackplate). In my case I was using nylock nuts. It is a 'galling' predicament to find yourself in. The easy remedy, and as I found out, the correct procedure is to use bronze nuts and lock washers. This is how outboards are usually mounted.

Harpoon Harry, all loosened up

Arch Autenreith posted 10-23-2002 09:35 AM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
Me too. Installing a jack plate this summer with brand new ss bolts w/nylock nuts. Went on with no problem. 2 minutes later broke the bolt off trying to remove. As John says it was gauling but I have never had that happen before (that I can recall).

Anti-sieze or similar of course would work but since I've never had it happen before I didn't think of using it. Just one of those things I guess.

Arch Autenreith posted 10-23-2002 09:37 AM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
I just said it went on with no problem. I was wrong. The nut wasn't going on easily so when I tried reversing that's when it broke.
BOB KEMMLER JR posted 10-23-2002 10:09 AM ET (US)     Profile for BOB KEMMLER JR    
well it looks like i might have to break the two on the jackplate and four on the transom plug i made,glad i been eating my wheaties.thanks for the info guys
ShrimpBurrito posted 10-23-2002 12:40 PM ET (US)     Profile for ShrimpBurrito  Send Email to ShrimpBurrito     
Bolts seizing as you describe is particularly common with the Nylock nuts. As you tighten it, little pieces of the nylon get ground off and accumulate in the threads, causing the nut to lock. Anti-seize works fine, but a little squirt of motor oil on the bolt works perfectly too.
Jiles posted 10-23-2002 01:51 PM ET (US)     Profile for Jiles    
In my line of work, I use a lot of stainless bolts and nuts. I have never had a bolt or nut "gauld" that was high quality. Most mounting hardware is cheap grade from foreign countries like China! Use high quality and lessen your problems. To lessen the problem, you can use hardened brass nuts. Stainless to stainless in low quality will, sometimes, 'gauld". I always use grade 5 or grade 8 bolts and nuts. This higher grade hardware is stronger and is marked for identification. My 2cents---?
Arch Autenreith posted 10-23-2002 02:00 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
Jiles or others:

Can you explain in detail (more or less) in laymans terms what happens or why metals gauld?

The threads appeared clean on both the bolt and nut but I didn't look at them carefully.
When screwing one on it started to tighten for no apparent reason to the point of seizing.

Very baffling to a non-metalurgist like me.

dreid posted 10-23-2002 02:16 PM ET (US)     Profile for dreid  Send Email to dreid     
bdb, you answered a question that's bugged me for years. In refinishing my mid-'80s Montauk and later O/R18', I took nearly everything apart. Was really curious why all the old origional hardware seemed to feature stainless screws and bolts, but bronz nuts. So it's suposed to be that way for a reason! Glad I replaced the old nuts in most applications.
lhg posted 10-23-2002 02:58 PM ET (US)     Profile for lhg    
I've had to hacksaw a few Nylock nuts off also, before I learned the hard way. I believe Shrimp Burrito's explanation is correct as to the reason. To prevent "galling" (rhymes with "falling") a dab of grease or anti-seize in the nut does the trick. This is why Mercury supplies engine bolts with new engines, most of which are fine thread 1/2" and with BRONZE nylock nuts. But these special bolts & nuts are hard to find locally in the shorter lengths needed for engine-to-bracket installation, and generally not available in marine stores.

An anti-corroding hint for those installing jack-plate style brackets is to put the nut on all bottom sets of bolts on the OUTSIDE, with about 3/8" thread exposed after bolt is tightened. Then buy the Mercury aluminum based (not zinc aftermarket variety) anode nuts (the ones with the rounded ends) and screw them over the bolt ends. You will be amazed how these sacrifice, protecting the bracket & engine itself.

Jiles posted 10-23-2002 03:58 PM ET (US)     Profile for Jiles    
Arch Autenreith----I am not a Metalurgist, I am a tool and die maker and a mechanic. The best way I can explain "gauling" is that it is metal fusion. That is to say there is interference between the two metals, usually both soft, and they litterally melt at the threads, and metal is transferred. Similar to cross-threading. EVERY time I bolt something together, I make sure, with my fingers, that the nut will go full depth on the threads. If it doesn't I make it right. I bought am item , back a few years ago, and fine thread nuts were supplied with course thread screws. As I am sure this was not true in your case, I would blame the problem on poor quality metal. Many people have misconceptions about stainless steel. MILD stainless has less tensil strenght then mild steel! Put a stainless nut on top of a battery, and see what happens in a few days. With a NEW nut and BOLT, the nut should have a very small amount of wiggle. This is true with NYLEX untill you enter the plastic. --Just MY 2 cents again------
weekendwarrior posted 10-23-2002 04:00 PM ET (US)     Profile for weekendwarrior  Send Email to weekendwarrior     
I learned a lot reading about the bolts, never had that happen to me. Neat idea with the sacraficial bolt caps too! Do you have a similar idea for bolts on the trailer (will this work in the open air)?

For cutting the existing bolts off I recommend an air cutoff tool if you can get in there with it. I use it all the time to remove corroded trailer bolts and there's nothing equal in bolt cutting power. But be very careful and patient, you only have to barely touch something with the disk to put a good size nick in it (such as your nice jackplate).

Arch Autenreith posted 10-23-2002 04:37 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
Thanks, Jiles.
(The following is what I also searched that satisfies this anal curiosity I have.)

Galling Adhesion
The term galling does not have an agreed on definition. In Europe, the wear community uses the term scuffing in its place. The Organization for Economic Co-operation and Development, Paris (OECD) defines scuffing as localized damage caused by the occurrence of solid-phase welding between sliding surfaces, without local melting.


Mild Wear, Severe Wear and Galling
These terms are used with specific meanings. They are in relation to unlubricated sliding. Click on lubrication to see the effects on adhesive wear of adding an oil or grease.
Mild wear is characteristic of dry sliding metals where the conditions are such that the naturally protecting oxide can continuously reform at the sliding contact, so acting with a degree of dry lubrication and reducing the wear rate. It also occurs with hardened alloys (usually steels) when, even under high contact loads and speeds, the underlying substrate can support the oxide and prevent its disruption by deformation below it.
Severe wear occurs (generally in soft metals or alloys) when the conditions are such that the oxide is disrupted at a greater rate than which it can reform, so that clean metal is exposed below and massive adhesion occurs between the mating surfaces.
It is not uncommon for soft materials to show sudden transitions between these two wear regimes. With mild steel at low load, mild wear results. As the load is increased, a point is reached when the oxide cannot keep pace and there is a sudden 100-fold increase in wear rate. At even higher loads, the frictional heating is such that the oxidation rate rapidly increases and can again form a protective layer; and mild wear is re-established.
Galling is a particular form of very sever adhesive wear reserved for materials that have thin, brittle oxides that are easily disrupted under load. Stainless steel fasteners and couplings are an obvious example. - The Poeton Guide to Coating Selection.

Jiles posted 10-23-2002 05:54 PM ET (US)     Profile for Jiles    
Thanks--Arch Autenreith-- Solid-Phase Welding--WITHOUT MELTING. Very informative. I just figured the metal at the thread contact was superheating and that was why the nut got hot. Proves we can all learn something new everyday. I personally use a lot of never-seize but on some applications I figure if it goes together smoother it will, unwantibly, come apart smoother. Spark plugs, and such, that will have to come out eventually, get my vote for never-seize.
triblet posted 10-24-2002 03:45 AM ET (US)     Profile for triblet  Send Email to triblet     
Wait a second, Shrimp Burrito: the nylon
is AFTER the threads. No way the nylon is
going to get in the threads. And no way some
wimpy nylon is going to jam a bolt till it

Galling is something some metals do (SS,
Aluminum, why is it most of the ones
interesting to boaters???). Anti-seize is
a good idea. Arch explained it pretty well.


Clark Roberts posted 10-24-2002 07:57 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Get a pipe extension for wrench and break the bolts! Clark
ShrimpBurrito posted 10-24-2002 12:32 PM ET (US)     Profile for ShrimpBurrito  Send Email to ShrimpBurrito     
Good point, Triblet. Maybe locking occurs more often with Nylock nuts because you have to apply more torque from the very beginning. No substantial torque is applied to non-Nylock nuts until you start to tighten, which would likely only be a few turns at most.

This site is pretty informative on the subject:

hauptjm posted 10-24-2002 12:32 PM ET (US)     Profile for hauptjm    
I like Clark's idea!! As my Dad used to say when he would get frustrated while working with certain thing, "If it doesn't fit, force it. If it breaks, it needed replacing anyway."
lhg posted 10-24-2002 02:30 PM ET (US)     Profile for lhg    
All I know is that it only happens with Nylock nuts, and mostly with the larger sizes only. Why? Whaler uses tons of smaller size nylock nuts on everything they install in the boats, with no problems on these smaller sizes. It's the 3/8" and larger that tend to seize up. So it must have SOMETHING to do with the nylon, when trying to back the nut off.

A regular nut, with lock washer, will not seize, at least it has never happened to me.

Arch Autenreith posted 10-24-2002 02:31 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     

The interesting part of the nut/bolt-in-case was that even though it started on easily enough (maybe 1 ˝ to 2 turns and BEFORE it contacted the nylon) it started to get tight. It was ˝ inch coarse thread btw. And as the nut continued down the shaft of the bolt it was visibly evident it wasn’t cross-threaded but we couldn’t figure out why it was getting continually harder to turn until it finally stopped turning. Period. We were scratching our heads trying to figure out why it did that and when we tried backing up it wouldn’t budge either and finally just sheared off. (We did have to use a pipe-extender, Clark!)

I also remember the tolerances at the beginning between the nut and bolt being a little ‘tighter’ than I would have though. After that we put a little lube on the others and they worked fine.

hooter posted 10-24-2002 05:33 PM ET (US)     Profile for hooter    
sure seems like a bunch'o nuts here.
where2 posted 10-25-2002 12:37 PM ET (US)     Profile for where2  Send Email to where2     
As you tighten SS to SS, little SS shards come off the threads, especially on the larger threaded bolts. (Look at a large SS threaded bolt, the threads are not nearly as smooth as those of a typical steel bolt.) As the two parts draw together, the little SS shards flaking off bind up the two surfaces passing in close tolerance to one another. the more you turn, the more SS shards flake off and bind the threads. Using oil or grease or anti-seize on the threads of one part lubricates the material reducing the friction that takes the shards off, and helps you get everything tight before something binds up and breaks. Nylon Insert nuts tend to bind more frequently because as you tighten them, the nylon doesn't get started being cut by the SS bolt until after it has already put strain on the SS threads. Although you may think the threads are uniformly spaced peak to peak between the SS and the nylon parts of a nylong insert nut, they aren't, and that is part of the reason they don't come off by themselves. That little amount of tension similar to cross-threading keeps the nylon nut from backing off as easily.
skookum point posted 10-25-2002 12:47 PM ET (US)     Profile for skookum point  Send Email to skookum point     
Same story here. I installed a kicker bracket this spring using 3/8" stainless bolts and nylocks purchased at Boaters World. All four seized up and had to be broken off. I've used alot of stainless steel fasteners over the years and this has never happened before. Like Jiles, I suspect it's a quality-of-manufacture issue. Lots of stainless boat fittings and fasteners coming from China now.

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