Stainless shackles

Anonymous · Post by **Anonymous** » Mon Aug 23, 04 10:02 pm

I need to raise the rear of my charger slightly but cannot afford new leaf springs so I thought I could make some slightly longer shackles from stainless stee.l But before I do I need to be sure that it is safe to do this. Has any one else done this or is it a big no no. I can make them no problem but am not sure if stainless steel is up to the job. Any advise will be greatly appreciated............... Matt.

Alex · Post by **Alex** » Mon Aug 23, 04 10:03 pm

I don't think I would be making them out of stainless.....

Dave-R · Post by **Dave-R** » Mon Aug 23, 04 10:25 pm

Get your springs re-tempered for around ?80 or less. Do it once and do it the right way.

MrNorm · Post by **MrNorm** » Mon Aug 23, 04 10:29 pm

Agree - don't use stainless.
And really...don't do it at all! You're really papering over the cracks and with a suspension system you don't want to be taking risks. If nothing else you might even find your insurance company would refuse to pay up if you had an accident with extended shackles. Really! I've heard of such cases.

You could always get your old springs rearched.

(oops Dave beat me to it)

Kev · Post by **Kev** » Mon Aug 23, 04 11:33 pm

Why the bigno-no on Stainless. Yours meturgyliky....

Anonymous · Post by **Anonymous** » Tue Aug 24, 04 6:53 am

Some good points there, I'm glad I asked now but why not stainless? Is it becuase it is softer than other steels? I will get the springs re-tempered but will do that over the winter as I have enough to do just trying to get the car back on road. I can live with it for now though.

Dave-R · Post by **Dave-R** » Tue Aug 24, 04 9:16 am

I think stainless is brittle and snaps. I have seen stainless front suspension parts on hot rods fracture before.

Anonymous · Post by **Anonymous** » Tue Aug 24, 04 9:36 am

Hi Dave. The reason I ask is that we build pharmaceutical machines at work all out of stainless steel and I always thought it was strong and have never known any part to fail. The only area most likely to fail would be the weld. Granted the two are completely different applications and under different forces etc. I'll definitely go the re-tempered route though.

db · Post by db » Tue Aug 24, 04 10:35 am

I bow to your greater technical knowledge gents but i have to say i've had all manner of brake, supension and steering parts made in stainless, including welding. I've used 'em on cars and bikes and used 'em hard and i've never had one fail. I do tend to over-engineer stuff tho... I've heard a figure of losing around 20% strength over steel so if your part is 30% bigger- should be ok??

MrNorm · Post by **MrNorm** » Tue Aug 24, 04 12:35 pm

I've forgotten most of my Metallurgy knowledge (and it wasn't much to start with

), but because of the high Chromium content stainless steels are harder to weld (not a problem here) and are not as ductile as carbon steels plus are more suceptable to notchs and stress raisers - which pretty much aligns with what Dave said. And they are not as strong

That said, there are many different grades of Stainless (ferritic, austenitic martensitic, all of which have different strengths and weaknesses), so if you know what you're doing and what type of stainless you have, no reason it could not be used IMHO. But since I personally (and probably many of us) don't know that, I'd play safe and go with a stronger cheaper alternative (though not in this case as discussed!). For the same reason I'm limiting my use of stainless fasteners as on a different thread.

Experience is as good or better than theory, so Paul I'd keep doing what you're doing!

Just my 2c, I am by no means an expert!! I'd think Trev would know a thing or too about it?

Holly · Post by **Holly** » Tue Aug 24, 04 5:32 pm

If you can get your hands on the right stainless steel alloy it can be made with the right properties, Firth Rixon's Sheffield site used to do this kinda stuff, but they started at 200 units, and VERY expensive

(I used to work for them, very customer orientated)

Bananarama! did wear resistant steel alloys and armour plating (that was all classified, shame as it was neat), but thats by the by ...

(that Bananarama is my home town BTW - the swear filters not too bright

)

Anonymous · Post by **Anonymous** » Tue Aug 24, 04 5:58 pm

and are not as ductile as carbon steels

Carbon steels display less ductility the higher the percentage of carbon.

But I would tend to agree with most of you mob, stainless is not advisable unless you have calculated all the stress' and sheer forces etc and selected the right material for the job.

I've heard all sorts of things about welding stainless, personally I have never had any problem with it. You are supposed to TIG it but at work we generally MIG it with stainless wire and loads of heat. It seems to hold up ok but I don't know what it is like after 10 years or so. I have MIG'ed in stainless plate onto mild steel with mild wire before and the results were fine for the job, but it wasn't a high stress area. I think there are supposed to be problems with corrosion associated with mixing the two?

TrevD · Post by **TrevD** » Tue Aug 24, 04 7:37 pm

Stainless is a mine field , many grades all having diferent properties , we use corrosion resistent steels in the aircraft industry that make mild steel look like putty , verry hard to machine and verry strong .
if i recall my youth , all extended shackles were made from 1/2" thick steel , if you dont need to go too high i see no reason why you shouldnt use 1" x 1/2" stainless but as already mentioned check your insyrance .
on the other hand i know if some alloys that are lighter and stronger than mild steel ( i made a complete billet front suspension for a rod abbout 5 years ago and it is still working ok , no breakages).

Anonymous · Post by **Anonymous** » Tue Aug 24, 04 10:06 pm

Blimey there's alot of long words in there. My knowledge goes as far as there is 304 and 316 stainless steel. Best be on the safe side and as Dave said do it once and do it right. Thank you fellas............ Matt.