Which metal for nuts and bolts?

[Bob Wild]

I’ve been building my Fire King for a year now. I notice that many of the nuts and bolts that have been in for a while are starting to look a bit tarnished as if starting to go rusty. That’s not pretty to me. So, I hit upon the idea of replacing them with stainless steel ones. Is this a silly idea or are there any alternative solutions?

Bob

 

[myrickman]

Not at all Bob. A good friend got me making all my fasteners out of 303 hex to replicate the old style high crown hardware. It machines and taps easily while still looking great years out. Is it a PITA?...yes, but you’ll only make them once. Of course you could always source commercial SS, but they still have that store-bought look.

 

[SmithDoor]

I’ve been building my Fire King for a year now. I notice that many of the nuts and bolts that have been in for a while are starting to look a bit tarnished as if starting to go rusty. That’s not pretty to me. So, I hit upon the idea of replacing them with stainless steel ones. Is this a silly idea or are there any alternative solutions?

Bob

Nuts can made out 12L14, 4140, brass basically any metal.
What is the thread made out of?

Dave

 

[Mike Ginn]

Hi Bob
I've been sand (actually ground glass) blasting my nuts and bolts and the using clear mat lacquer as a finish. This works well and you get a pleasing dull grey finish. I do the same with brass which gets rid of all the marks and leaves a mat dark golden finish. This process works well on slightly rusty parts.
Mike

 

[tornitore45]

12L14 Machines beautifully BUT rusts in a blink of an eye.

 

[SmithDoor]

I have made thousands of axles with 12L14. It is great metal for finishing.
I started zinc plating it got costly.
As years when on just used as machine.
Today I am retired I just use gun bluing from big 5.
I did buy from Home Depot copper sulfate aka root kill in plumbing for copper plating.

Dave

12L14 Machines beautifully BUT rusts in a blink of an eye.

 

[delalio]

I heat blackened some bolts for my Stuart 10V. you can see them on this video. They look pretty nice, and are rust resistant. Non rust proof I dont think. Although no signs of any yet.



They are tiny, so I just put them on the gas burner for the steam engine until they were red hot, then dropped them in some used car engine oil. Once cooled, I fished them out with some tweezers and mounted them. Yes the heat could have heat-treated them, and made them very brittle. I'm not sure how much yet. I'm hoping they dont snap on the next engine strip-down & rebuild.

 

[jack620]

I found that oil blackening comes off if you wipe any kind of solvent on it. For example, when cleaning with kerosene or coating with WD40.

 

[delalio]

I found that oil blackening comes off if you wipe any kind of solvent on it. For example, when cleaning with kerosene or coating with WD40.

Oh thats always good to know. I havent put any solvent on the model yet as it'll affect the paint, but thanks for the heads up. I'll be very careful when giving it a clean!

 

[deverett]

I oil black most of my small home made lathe/milling machine tools and have never had a problem with the blacking coming off during normal use, but it does eventually wear off. I think the secret is to ensure that the parts are completely oil/grease free before blacking.

If you like the finish of blackened fastenings, just carry on using it.

Dave
The Emerald Isle

 

[L98fiero]

Yes the heat could have heat-treated them, and made them very brittle. I'm not sure how much yet. I'm hoping they dont snap on the next engine strip-down & rebuild.

Unless you got the screws almost white hot, you probably didn't seriously affect the steel, for machine screws that size, they're probably low phosphorus, low carbon steel so they won't harden or get brittle without being seriously overheated.

 

[delalio]

Unless you got the screws almost white hot, you probably didn't seriously affect the steel, for machine screws that size, they're probably low phosphorus, low carbon steel so they won't harden or get brittle without being seriously overheated.

Ah cool. That's good to know.

They just got upto a dull red heat.

 

[HennieL]

I’ve been building my Fire King for a year now. I notice that many of the nuts and bolts that have been in for a while are starting to look a bit tarnished as if starting to go rusty. That’s not pretty to me. So, I hit upon the idea of replacing them with stainless steel ones. Is this a silly idea or are there any alternative solutions?

Hot gun blue would be another alternative - black nuts and boltheads just look "better" in my humble opinion - but stainless would work great as well. If you wanted high tensile you could use any of the stainless 400 series steels, then harden and temper back to a nice spring steel hardness.

 

[windy]

I have used gun blueing paste you have to oil the parts once the paste is washed off.
It's very acidic the one I used so follow the instructions well.
Have used it on steel parts of my flash steam hydroplane which was submerged in water many times.
There are a few different types of gun blueing available.

 

[a41capt]

Hot gun blue would be another alternative - black nuts and boltheads just look "better" in my humble opinion - but stainless would work great as well. If you wanted high tensile you could use any of the stainless 400 series steels, then harden and temper back to a nice spring steel hardness.

I use a product called Van’s bluing solution for cold bluing. I gently warm the part to be blued after thorough degreasing, and it gives me an extraordinary uniform black, especially if submerged in the product. No corrosive fumes, no hot salt bath, and consistent results over a wide range of materials.

John W

 

[a41capt]

This is an example of the finish achieved with Van’s. It is a barrel nut wrench I built for my son to complete a competition AR-15.