The Danger with Stainless Steel Bolts

Public Service Announcement.

[polarisindytrail]

I bed to differ, I have made that mistake a lot more than once

[someoftheyouse]

The other hazard we found was if you drop them into something they are 50% harder to recover on account of 300 stainless not believing in magnets and therefore being immune to their beguiling influence.

[sivalley]

Core Memory Activated: Back in my days as a nuclear plant operator in the US navy we had stainless infrequently operated primary coolant valves that had caps that fit over the entire bonnet assembly that were sealed with a self-presurizing metal o-ring. The valve caps themselves had acme threads to reduce the chance of galling, but every time the cap was removed we had to clean the threads and apply colloidal graphite (neo-lube) to both threaded surfaces and we had a special procedure for re-installation of the cap that basically said the cap must be spun on no faster than 30RPM until the surfaces mated the O-ring and then when torquing, 5 seconds per flat and 5 seconds between flats. We never had a galling incident but did have a scare when the brass insert that had the stem operating threads fail and the valve couldn't be shut. Thankfully it was part of a double valve isolation and the other valve was working properly.

[stickyfox]

I learned as an Army mechanic that there's a much quicker way to remove a galled bolt than sawing it off. Just get your biggest breaker bar, and keep tightening it until it shears off.

[joshboileau]

We actually stopped using stainless steel bolts at our aquatic center. We switched to galvanized bolts because we were finding that the chlorine in the air and water were corroding the stainless bolts from the inside. We would find a stainless bolt with the head missing and the inside would be corroded away. Maybe it was the wrong grade of stainless. The galvanized seem to hold up better for our use and are much more apparent when bad

[brianyoung]

I worked with 316 stainless hardware at water districts and we paid for 100% inspection on the threads and used antisieze on all of them.

[YoureWierdImNt]

remember kids, cross-thread is the tightest thread.

[dkeith]

The Galling problem is especially bad if the SS bolts and nuts are put on fast, as with a battery operated tool. My brother used to use SS bolts and SS nylon lock nuts and he had a failure rate of 10 - 20% where the bolt would seize, and you'd have to snap it off to remove it. Nickle never seize helped, but was not a cure. The only thing that really worked was to only use hand tools and put the bolt or nut on slowly. Interestingly, this type of condition, known as Galling, Friction welding, Cold welding happens in milliseconds and once galled, the fasteners can only be removed by cutting or snapping them off using great force with wrenches or ratchets. It only occurs, to my knowledge with SS, Titanium and Aluminum.

[Number_]

As soon as you crack the seal on a can of never-seize, it instantly appears on the back of your truck seat and the seat of your first girlfriend's pants, among countless other locations, even though it has been over a decade since you have seen her. 😂

[Hawk]

So for the military usage we supplied, the approved procedure is to use different alloys of stainless in the nut and bolt, they must both be passivated, and they get never-seize appropriate for the environment. Different alloys are less likely to self-weld to each other, the passivation layer prevents bare metal on metal contact, and the base of the never-seize (zinc or copper) provides a further layer of separation as well as a galvonic barrier.

[jaydak]

I work on communication towers. Lots of antenna brackets are stainless u-bolts with stainless nuts. They gall all the time. To remove them, I typically crank the smaller ones until something breaks. The bigger ones require a saw or grinder.

[CheezyDee]

I found this out the hard way when I decided to "upgrade" the hardware for one of my company's process cooling water pumps. Apparently stainless bolts and stainless lock nuts will gall when tightened with a 1/2" impact 100% of the time.

[atypicalbnc]

When doing marine work we had no choice but to use stainless. Tef-Gel was the go-to, as it worked well to prevent stainless-on-stainless galling and did pretty well when using stainless fasteners to secure deck fittings made of dissimilar metals.

[Hydrazine]

Just use ARMCO NITRONIC 60 stainless steel (UNS S21800) nuts and bolts and you're good without anti-seize. Admittedly, that specific grade of fasteners are few and far between, and expensive.

That particular stainless steel grade was once specifically developed in the sixties by ARMCO (later AK Steel, now CLIFFS) to be galling resistant. It's also exhibiting an excellent high temperature oxidation resistance _and_ resitance against cavitation erosion.

Fun fact: a lot of thread inserts are made from NITRONIC 60 for this very same reason.

[ragdolltrucking]

I just want everyone to know, this guy was the sole reason I decided to start a YouTube channel, I've been watching his videos for 12 years and it's given me hope that the world still appreciates smart, working class people

[Adamsadventures]

I work for a medium sized city water department doing repairs on mains, valves, hydrants etc. Depending on the soil and moisture held around the bolts, I've dug up nearly 100 year old square head carbon bolts still in decent condition. And ones 20-30 years old nearly rusted to nothing. We replace exclusively with stainless or a special coated bolt. Generally for the stainless we use never seize when doing so. But muddy muck seems to work just fine to keep them from galling as well.

[jakeriff]

lol of course you went on vacation and decided to inspect the infrastructure 😂

[stevewaldorff]

I repaired and assembled a lot of stainless steel, steel mill pumps and my go to was always molybdenum disulfide grease.

[doublepenn]

The key is to torque them so tight they mangle the threads. They will have to be cut out.... Besides, if anyone asks; it's designed to sway.

[zachary]

I had an architectural job that required a large amount of smaller stainless fasteners. We used the graphite dry lube and wee very happy with the results. Before we started using the spray graphite every 4th or so fastener would gall up and brake off.