sprung steel expert

[barnfind]

Anyone on here have expertise with this? My conv needs new inner rocker reinforcement. I've checked with a few experts on this and its supposedly made from this type of metal 3/16 (sprung steel). I've done some web searching on the subject with no answers. any advice on this?

 

[Photon440]

I haven't heard of them being made of sprung steel. Maybe I'm not thinking of the same part you're talking about. These go in the inner rocker,do they look like this?

http://www.classicindustries.com/mopar/parts/mm8313.html

 

[barnfind]

Thanks for your input, but these basically run the length of the rocker panel with several bends from a brake. They're bent into a sort of L shape and mount upside down. So if you're looking at them without the outer rocker installed, it would be where your sill plate and the outer portion of the rocker . They mount inside to add strength in the middle when you open both doors on a unibody covertible. Currently, I'm looking at 3/16
A-36, grade 50-80 to do this with, but I'm wondering if anyone has done this. or if I'm on the right track here.

 

[Cranky]

A 36 is a standard steel alloy that is common in structural steel shapes and is really not anything special. Sprung steel...makes me think of spring steel. 3/16" thick? Only 316 I know is 316 stainless and that would not be used for rocker contruction.

 

[barnfind]

Correct not for outer construction, I'm looking at inner 3rd panel (conv only). Ive found a set for them but the price tag is $2500. I think I'm gonna take a stab at building my own. The sprung part threw me at first thing it had a curve in it as in a leaf spring. I've found it to be a property done to the steel. I don't know what ma mopar made these from.

 

[Photon440]

If you're going to try building your own, would you be able to press up a new rocker panel on a brake by using a thicker gauge of steel instead of making the inner part? Back in the frame days (1950's) Plymouth used thicker rockers on convertibles. Maybe you could use this idea.

 

[barnfind]

huh, there's an idea, thanks for your response. Did Plymouth use full x frames under the bodies like other manufacturers? I'm not up on 50s mopar conv. but I do like em. The more I read on the subj it seems to me its just tempering quality. So the metal returns to orig form, thus giving it a spring like effect, again I'm certainly no expert here. If it has too much tempering it becomes brittle. Certainly not a good thing while driving down the road. It also wouldn't be good when both doors are open, and occupants entering/exiting. If its special type of metal and its spot welded to the outer rocker that heat would have effect on its spring like properties. Just spitballin here. I appreciate all the feedback.

 

[Photon440]

Yes, Plymouth used conventional looking frames until they went unibody in around 1960. (Imperial continued to use frames until 1967) Here's what they would have looked like - this is actually a DeSoto frame:



This is the article where it states the differences in metal thickness for the old convertible rocker panels, which is the information I think you're interested in. Actually, the entire read is fascinating as this guy restores a piece of junk bit by bit. Can you imagine an entire car in an electrolysis bath to remove all the rust?

http://www.jalopyjournal.com/forum/showthread.php?t=779564&page=4
(look at entry #66)

-=Photon440=-

 

[barnfind]

Photon,
I haven't looked at that thread in awhile now. Hes moving on that one. Yes, I saw #66 and I thing I'm gonna go that route on mine as well. Hes very talented making something outta nothing.
Since mine is a unibody I'm thinking its still going to be in addition to the inner piece. I know a welder that has access to an industrial brake (they build truck frames) to make this piece. Its down to material selection at this point. I may have to find someone to do a hardness test on the orig to get a better idea. It was also suggested we do a drill test to see the shaving quality / color (I haven't heard of this one either)
The more I read it seems there's a lot of variety with nickel and temperament of metal, up to high carbon, stainless too..
The search continues...

 

[Malicious]

Your right, 'sprung steel' is a tempered steel that will return to its shape. Like a leaf spring I guess. Makes it more flexible but wont hold a shape after being 'sprung'.

Because of that you don't 'buy' sprung steel you make it. You would make whatever you need then get it tempered. Not sure where you would start looking, maybe a smelter? I do know of people that used to do it tho. They used it on reproduction swords. You'd cut and shape the blade then send it off to get tempered. Meant the sword had some side to side movement, but you could throw it on the ground, stand on it on uneven surface, even bend them nearly in half and have them spring back straight.

I would be careful when making this piece because it sounds to me like it would be made to be installed 'under tension'. So it would always be push both front and rear half up and together, if you catch my drift. You may have to make it with less angle then it seams to have installed, so you have to bend the reinforcement it to place. Like a encapsulated coil on suspension.

HTH

 

[Photon440]

I wonder if this would work. Look at AMD's catalog on page 10. They list both inner and outer rocker panels. Then again, it might just be referencing the 'inside the car' part.

http://www.groupenetwork.com/documents/AMD_Mopar_Catalog_2010.pdf

Also interesting, although for GM, this page specifically mentions the high strength steel used for inner panels. (2nd page)

http://www.mycertifiedservice.com/g...10-2011/10_Rocker_Inner_Panel_Replacement.pdf

 

[barnfind]

Your right, 'sprung steel' is a tempered steel that will return to its shape. Like a leaf spring I guess. Makes it more flexible but wont hold a shape after being 'sprung'.

Because of that you don't 'buy' sprung steel you make it. You would make whatever you need then get it tempered. Not sure where you would start looking, maybe a smelter? I do know of people that used to do it tho. They used it on reproduction swords. You'd cut and shape the blade then send it off to get tempered. Meant the sword had some side to side movement, but you could throw it on the ground, stand on it on uneven surface, even bend them nearly in half and have them spring back straight.

I would be careful when making this piece because it sounds to me like it would be made to be installed 'under tension'. So it would always be push both front and rear half up and together, if you catch my drift. You may have to make it with less angle then it seams to have installed, so you have to bend the reinforcement it to place. Like a encapsulated coil on suspension.

HTH

Thanks for your input on this Malicious,
Have you or are you working with this process? I've found several varieties of metal that have temperance / annealing done in flat stock form. I'm travelling out to Alaska for a week. Then will be back at it. I'm planning to carefully disassemble the rocker for better viewing and eventual testing of this metal. The easiest way someone explained this to me was think of your cars (older mopars) antenna mast (stainless) It whips in the wind, carwashes etc. and returns to shape unless pushed beyond its limit. Same as the swords, carb clips etc. Im still looking what to make this out of, buy stock steel and do tempering to it or buy something already treated and form...


Photon. thanks for the input, This looks like the right idea, but is an inner rocker. If I were to put these together there's still one more piece to this puzzle. I'm not finding much for info on the subject. Ive seen a few posts on other forums where someone has taken and patched these up. Not the way I want to go, and seems like it could go wrong further down the road...