Lubricating Stainless Steel nuts / bolts , etc ?

[Jules]

I'm using stainless bolts with stainless nyloc nuts or stainless dome nuts assembled with "silver goop" in places that "show", but cant comment on durability for a while yet, I'm afraid!
I think the best compromise Richard is to use the lubricant because everybody knows that SS WILL gall up otherwise, but then make a point of checking bolt/nut tightness on a regular basis - just as the old manuals used to advise actually!

[RichardL]

Well, I must admit to being buoyed by Rex's comment regarding flat washers and lock washers together. I had bought the studs, nuts and flat washers as kits, so I'm not inclined to spend the money and time it would take to come up with stainless Nylock nuts in BSC (I believe that's right, the thread type, that is). So, I've ordered internal-tooth stainless star washers and located copper-based anti-seize near me. On the possibility (maybe, likelihood) that lock washers aren't needed at all, having them isn't likely to make shaking-loose worse.

While looking for the star washers, I was amused that they could be had with tall teeth for more agressive grip. That was interesting, but they were only available in external teeth and recommended for nuts big enough to cover the whole washer, which mine wouldn't.

Someday, soon, I'll be on to another issue that also should have been easier than I make it.

Richard L.

[RichardL]

Man, oh, man. Stuff gets here fast from McMaster-Carr. About 24 hours from order to star washers on the porch.

So, I tested one of the engine-mount studs with the two-washer theory. Seems that the lead-in chamfer for the thread is almost large enough in diameter for the star points to miss the nut completely, but I'm planning to go with it anyway.

Also, found what I think will be a very useful chart for knowing the torque for lubricated threads (attached as picture and downloadable PDF). I won't be coming within more than 75% (if that) of any of these maximum values. Gotta test the good ol' hand feel.

Richard L.

Sometimes I discover ridiculous typos that have to be fixed. You know what I mean if you read the above before this edit.

[RDfella]

Very handy table that, Richard.
First thing that jumps at me is the difference between Stainless (type 316) and HT steel. It gives 45ft/lbs for 1/2", whereas the 1/2" cyl head bolts on my boat engines are torqued to 130ft/lbs. I know many people overestimate the strength of stainless, but the difference is still substantial.
On the other hand, I'm surprised silicon bronze is so high, and surprised monel is so low. The latter is often used instead of 316 when superior strength is required (eg boat propshafts).

[BSA_54A10]

When fitting sta washers I have found that you need to use the "wrong size " washers to get the tangs in the right position to do their stuff.

[Black Sheep]

Star washers were in days of yore discouraged as they can allow ingress of water leading to fun and games removing nuts and in particular through bolts 20 years down the line. Only applies to damp climates particularly where the gritters are out 8 months of the year. Ruddy things were out yesterday again.