[Larry Navarro]

What they don't tell you about stainless steel.
There are two main series of stainless steel 300 & 400. The 300 stainless which includes 18-8 is most widely used. There are many reasons why stainless is not the best choice.

Galling of threads: stainless provides a poor bearing surface and thus requires a lubricant to prevent thread damage during installation. Original equipment automotive fasteners are lubricated with a cadmium, zinc or phosphate finish and do not have this problem.

Low strength: Typical 300 series stainless is equivalent to a standard Grade 2 fastener making them unsuitable for many applications such as steering, suspension, brakes, engine, differential etc. That leaves only the body, where most OEM fasteners are Grade 5 !

Rust: The stronger 400 series stainless will rust ! In order to bring back the strength carbon is added back into the alloy causing surface rust to develop when exposed to the environment.

Loosening: All original equipment body bolts have some type of locking device. Most widely used is the conical spring washer. Conical washers do a great job of both spreading the clamping load on sheet metal and preventing loosening. The stainless steel fasteners sold today don't come with conical washers because of the cost to make them.

Design: Original equipment fasteners have numerous designs that maximize their effectiveness and function like flange heads, screw & washer assemblies and self-locking features. Most stainless fasteners offered for sale by the various vendors are ordinary universal commercial fasteners that are not designed for automotive applications.

Appearance: Because stainless fasteners lack the specialized designs common to automotive fasteners they often look out of place. The bright finish typical of stainless detracts from more important things like your engine! Many 300 series and most 400 series stainless fasteners will have some type of cryptic head marking that looks like Chinese (most stainless is imported) and does not match the remainder of your beautiful American made Detroit iron.

Not Needed: Chances are you are keeping your car in a dry garage and will not be driving it during the winter months on salted roads. So why pay high prices for something you don't need and that will not otherwise improve your car ?

Factory Stainless: Your car came with stainless in the right places. Most exposed exterior fasteners such as for headlamp/tailamp bezels, mirrors, lenses, scuff plates are already stainless. Very often the factory chrome plates over the stainless in order to provide good looks with corrosion protection.

[Larry Navarro]

What they don't tell you about stainless steel.
There are two main series of stainless steel 300 & 400. The 300 stainless which includes 18-8 is most widely used. There are many reasons why stainless is not the best choice.

Galling of threads: stainless provides a poor bearing surface and thus requires a lubricant to prevent thread damage during installation. Original equipment automotive fasteners are lubricated with a cadmium, zinc or phosphate finish and do not have this problem.

Low strength: Typical 300 series stainless is equivalent to a standard Grade 2 fastener making them unsuitable for many applications such as steering, suspension, brakes, engine, differential etc. That leaves only the body, where most OEM fasteners are Grade 5 !

Rust: The stronger 400 series stainless will rust ! In order to bring back the strength carbon is added back into the alloy causing surface rust to develop when exposed to the environment.

Loosening: All original equipment body bolts have some type of locking device. Most widely used is the conical spring washer. Conical washers do a great job of both spreading the clamping load on sheet metal and preventing loosening. The stainless steel fasteners sold today don't come with conical washers because of the cost to make them.

Design: Original equipment fasteners have numerous designs that maximize their effectiveness and function like flange heads, screw & washer assemblies and self-locking features. Most stainless fasteners offered for sale by the various vendors are ordinary universal commercial fasteners that are not designed for automotive applications.

Appearance: Because stainless fasteners lack the specialized designs common to automotive fasteners they often look out of place. The bright finish typical of stainless detracts from more important things like your engine! Many 300 series and most 400 series stainless fasteners will have some type of cryptic head marking that looks like Chinese (most stainless is imported) and does not match the remainder of your beautiful American made Detroit iron.

Not Needed: Chances are you are keeping your car in a dry garage and will not be driving it during the winter months on salted roads. So why pay high prices for something you don't need and that will not otherwise improve your car ?

Factory Stainless: Your car came with stainless in the right places. Most exposed exterior fasteners such as for headlamp/tailamp bezels, mirrors, lenses, scuff plates are already stainless. Very often the factory chrome plates over the stainless in order to provide good looks with corrosion protection.

[68GTOConv]

That's good info - thanks for sharing!

Mike M

[PMDRACER]

Thanks Larry!

[trigger]

I used a kit from Totally Stainless to assemble our '81 T/A. I was shocked at how easily the bolt heads could be twisted off.

However, the kit didn't contain any hardware for critical applications... the fasteners for the door hinges and hood hinges are the only ones I can think of that bear any significant load. They sure look nice, but there's no way I'd use them anywhere in the "guts" of the car. Stainless washers of all varieties are available just about anywhere... I spent an extra $15 or so on them. In my eyes, the kit was worth every penny since I have no garage and have been taking my sweet time assembling the car under a tree.

[PetesPonies]

like everything, there is good quality stuff and there is China crap. Good quality SS fasteners will have approx a grade 5 equality.

[78 GHOST]

Pete, Totally Stainless mentions in their catalog the "ordinary" stainless fastener strength is more like Grade 2. They do provide a special high strength fastener rated at Grade 8 or better.

[trigger]

It's worth mentioning that the fasteners supplied in the Totally Stainless kit I used had stronger black-oxide parts for all the heavier body fasteners like hinges, fenders, rad. suppourt, etc... The only ones I was scared of using were the body mount bolts and rear axle stop bolts, which were regular stainless. They make fine paperweights to hold all the receipts down.

[PetesPonies]

this backs up what I said. It al depends on the quality of the stainless. There are many qualities out there:

Stainless Steel Fasteners are corrosion resistant and used in a variety of high strength applications; some of these industries include: general hardware, construction, marine, and automotive. Stainless steel fasteners with 18-8 and A-2 specifications feature some of the highest tensile strength of any other metal screw on the market; a 1/4" to 5/8" stainless steel screw provides up to 125,000 psi. Only grade 8 steel has a higher tensile strength at 150,000 psi.

I am basing my opinion on tensile strength.

[PetesPonies]

here's a good chart...it shows how the stainless compares with the typical carbon steel graded bolts. Now this is the good stainless ) but it can be bought.

[69goatboy]

Having worked for a fasterer wholesaler in my youth and being an engineer now, I agree with the above. The 18-8 stainless is the cheap stuff. If you want decent strength stainless: specify 316 grade but be prepared to pay through the nose for it. We kept the 18-8 stuff on the floor with everything else but the 316 stuff was always locked up.

400 series is stronger but is mainly used in surgical applications. I don't think you can find 400 series fasteners.

[poncho455]

ARP sells a line of polished stainless steel bolts rated at 170,000 psi tensile strength. Here's a link to their site ARP.

[PetesPonies]

yes, here is their chart........

[larry davis]

Further to Larry N's discussion:
Stainless (CRES) is available in precipitation hardened (PH) grades that are equivelent to and exceed G5 & G8. They are expensive when compared to ferrous alloys but are the ticket for suspension components.
Most all type of lock type washers can be had from the split lock to the internal & external star types.
These PH and the other 18-8, etc... stainless fasteners can be available in a blackened versions that are more scratch resistant than the normal gold iridated coating on G8 ferrous fasteners. Most all of the above can be had from Totally Stainless, but they are quite slow on delivery. I use quite a bit of their stuff.
A lot of fasteners can be gotten from Grainger &/or Mcmaster-Carr.

[aj66gto]

I have a 66 GTO. that I'm doing a frame off Restoration. I would like to use stainless steel bolts wherever I can. I expect the frame to be back at the end of the month. I would like to use Stainless steel for the body mounts. What do you guys think and where can I buy them.

Anthony

[PetesPonies]

http://www.arp-bolts.com/pages/tech/tech.html
http://www.winkfast.com/index.htm

[bullheimer]

i got a flaming river stainless steering shaft. it's obviously not going to be soft. maybe that explains why it started to rust after 2 weeks. (i sprayed it with clear thereafter)

[Half-Inch Stud]

AGREED.

[Rob79TA]

what about stainless fuel and brake lines are they worth it?
any negatives to them?

[68convert]

Pete good reference chart. Thanks