-- has anyone ever used the stuff? Remarkably, elliptical SS tubing is available at rates less expensive than comparably shaped 4130. Larger production runs, I suppose -- the stuff is used for railings and things.
Any thoughts welcomed.
Stainless suspension tubing ---
-- has anyone ever used the stuff? Remarkably, elliptical SS tubing is available at rates less expensive than comparably shaped 4130. Larger production runs, I suppose -- the stuff is used for railings and things.
Any thoughts welcomed.
The tubing it sounds like you are referring to is an ornamental tube made to ASTM-A554. I just looked up that ASTM spec in my book, and the min yield strength allowed in that spec is 25 ksi for 304/316 SS. Of course, it may be produced to a higher strength than the minimum, but that isn't particularly high. We don't stock this particular tube (metals distributor), but the only time I have heard mention of it is for decorative applications like handrails as you mentioned.
I don't think I would want to weld that and have to rely on my welds as well as on the 25ksi.
If you want to do it cheap, use round seamless 4130.
Laverty has a good point. It would need to be properly back-purged and welded by someone experienced with properly controlling the heat input in SS. A weld that will hold a handrail for eternity won't necessarily be good enough.
In the past when I've made parts out of 304ss for racing applications, it seems the parts had a much shorter fatigue life than parts made of 1020 / 4130. A "real engineer" told me that 304ss is a bad choice for highly stressed components. The parts where weldaments, for motor mounts, and suspensions. Any real racing type of engineers like to comment?
I did a Google, and found some interesting info for engineer types...
http://www.dtic.mil/cgi-bin/GetTRDoc...f&AD=ADA397605
http://machinedesign.com/article/com...er-metals-1209
[FONT=Times New Roman]And don’t forget an A-arm is swept back at say, 45 degrees it is an ellipse to the airstream … albeit aero tubing is also more sleek and streamlined at the same angle;[/FONT]Originally Posted by RobLav
[FONT=Times New Roman]IMHO a slow track like Waterford, round tubing is only at a slight,disadvantage if any …[/FONT]
Just bought 1.6 x .71 x .049 for 15 bucks a foot
www.airbum.com/articles/ArticleDillsburgAero.html - Cached
this guy is a classic ...
Thanks, guys ---
-- am already onto Dillsburg for 4130. Just thought I'd take a look at this not-so-great option.
Again thanks.
chris
All the streamline tubing Dillsburg has is from China and is so wavy, it looks like spaghetti noodles. I would suggest tubing rolled by Plymouth Tube in Streator, IL.
We bought rolled tubing once (just once) from an outfit in IL back about '94 (don't remember the name, so I'm not going to claim that it was Plymouth Tube ). Total junk - not only did it have splits along the tight bend, but it showed dents where one of the rollers had a bump in it, and usually had a built-in twist along its length.
Be very careful where you buy your tubing from and inspect it carefully before accepting the shipment!
Unfortunately, the quality of the Dillsburg streamline tubing has suffered in the last few years as well.
You cannot buy directly from the mill, Plymouth Tube, unless you are buying truckload quantities. The tubing you bought may well have been manufactured by Plymouth, who has many locations around the US (all the streamline is made in Streator, IIRC), but you couldn't have bought it directly from the mill, so just because the outfit that sold to you was in IL doesn't necessarily mean it was made by Plymouth. Could very well have been, though. Regardless, it definitely shouldn't have been shipped like that, and they should have either replaced it or given a refund.
I don't mean to defend Plymouth Tube, btw. I have no affiliation with them (they are not even one of our tubing suppliers, as we don't stock any 4130 tubing), but IMO they produce the best streamline tubing. I don't even think anyone else makes it in this country at this point, so it's either them or China.
I had one of our purchasing managers inquire with Plymouth about ordering some streamline tubing so I could sell it to racers, and the minimum we could order was in the 40,000 lb. ballpark. That is a lot of lineal feet when you look at the weight/foot.
ETA: if you buy tubing, and they won't replace defective material once you have accepted the shipment, I would suggest finding somewhere else to buy it.
Again thanks to all --- and so ---
-- what's the best bet (by general consensus). Bite the bullet and go to Spruce? (Not the wood, the perveyor of 4130 steel streamlined tubing)...
Wow, the stuff is so expensive, and, unfortunately, our a-arms are long (the car uses a narrow keel arrangement up front). Anybody got any other great money-saving ideas in this area?
Chris
Aircraft Spruce or Wag Aero. Last I bought from Wag, the price was better and quality was good.
A while ago, Jay Novak suggested a place to source symmetrical streamline tubing.
http://www.apexspeed.com/forums/show...3&postcount=10
I assume that this is what I have always referred to as "Brun's tubing" because it is what he used on the DB-6. I would expect it to be cheaper, but not as sexy.
My last shipment came from Dillsburg and what I saved in the cost of the tubing, I lost in labor to polish every thing especially before welding and scrap because of dents.
You might try AED in Indianapolis. They are having some good quality material locally rolled. It looks very good but is not exactly MIL dimensions. The price was about Dillsburg at the time of my last order but the tubing lengths were 8' to 10' vs. random 20' from Dillsburg. The shorter lengths increase the scrap.
Go to Spruce or do as Swift did years ago and flatten round tubing using a press and a mandrill.
Streamline does have the cool factor. Now, if we could just convince them to make Reynolds 953 in a streamline profile, the whizzy bit drool factor would be maxed out.
I had to google. That is cool stuff.
Yeah, close to 300 ksi UTS, plus the variable wall thickness. Expensive. ZOMGWOW cool though.
Cool video featuring double-butted tubing:
http://www.soulcraftbikes.com/
Would be interesting to find out how it reacts to welding - what would be OK for a bike would/could be a disaster for FB a-arms.
Nice looking bikes, though.
Well, they do weld that stuff all the time without issue, and road bikes in general seem to be capable of failing welds with the best of them. That being said, I'm not going to be the first to use it on a race car.
Look at some of the stuff they used to make for steel bike frames. Varied wall thickness, rifled, with thickened ends for the joints. Unique tubes for each frame size.
I know you are preoccupied with trying to keep me out of prison, but we already mentioned variable wall thickness (term is double butted), plus that and the unique tubes are shown in the video.
[Dillsburg] I bought 20' and it looks great, no rust or dents ... China huh? ...will check, if so I'm Pi$$ed ......
Possibilities include:
Some of the Chinese stuff is fine. Maybe you got a good one. Is it also straight?
Vogel-song may have had some domestic stuff. Last I called there, he admitted all of the streamline stuff he was getting now was imported. That doesn't mean his entire inventory has turned over enough to be 100% imported.
If it doesn't have line markings that say Plymouth, it pretty much wasn't made here. Excluding the AED stuff.
4130 Symmetrical Tubing
Everything commented on regards dents / dimples , wavyness etc hold true in my experience also. We have a Swift 014 that uses a 4130 symmetrical elipse profile. As this profile was proprietary to Swift, that was the only source for A -Arms unless you go to a streamline /teardrop profile. In order to stay true to the OEM profile I went down the path of having a mill custom make some (a small truckload in fact !) After investing signifcant time money and effort to ensure dimensional and metallurgical specs were met, dealing with the mill to minimize quality defects such as dents etc, I now have the material quality where it needs to be. That of course is reflected in the cost (more than streamline).Yes, this stuff is expensive material, but you have to consider what its doing.
Regards Graham
Graham
I understand what you are saying, but my knowledge base so far (and I'm the first to admit that it isn't all-inclusive) is that high-strength alloys need lots of post-weld treatment to not go glass hard and brittle. However, that observation may indeed not include supposedly "non-heat-treatable" alloys.Well, they do weld that stuff all the time without issue, and road bikes in general seem to be capable of failing welds with the best of them. That being said, I'm not going to be the first to use it on a race car.
No argument here, that is certainly the way it usually is. I just can't help but think that if it were brittle, it would crack on skinny-tired road bicycles with no suspension. It's all moot as the tubing is available only in limited sizes and short lengths anyways, as each size is intended for a specific member on a bicycle frame.
Did anyone else watch the video and think, "Get the #&*@ing abrasive chop saw away from the machine tools?"
A quick search shows that it is a maraging steel, and as long as it is welded before age-hardening, it will not go brittle. Welding after fully aged will lose a bit of it's ultimate strength. Takes a special filler rod (supplied by Reynolds) to do the job properly.
Yes, I read that as well. I had assumed you had read it before, so I thought the issue was whether or not we believe their magical claims.
source for streamline 4130
Another good source for 4130 tubing (streamline and others) is Wicks Aircraft Supply in Highland Illinois. The stock is good quality..... and they will cut and ship any quantity same day.
Jerry Hodges
Soulcraft.
I wonder if those Soulcraft folks are as surgical and precise when nobody's looking ... I mean do they occasionally yell and curse and suffer through loud machines and bad music on the radio like normal folks or not? Wow, they make it look glamorous...
And something tells me that material could work... if someone wanted to do an extensive and carefully figured destructive test program. Unfortunately, that ain't me so I'll continue trying to find a way to use 4130 without breaking the bank...
Thanks for that link.
C
Apparently the alloy was developed by Carpenter and produced at various foundries over here. Carpenter has a very good reputation (as far as I know) about what it produces and their claims, so I'd be hard pressed to quibble with what they say its spec are.
I'd still want to run a bunch of tests before using it for a-arms, though!
What if ---
a guy were to try this stuff for a-arms, but say at a 10 percent oversize (gauge), and then be real vigilant with dye penetrant (and etc.) during a testing phase.
What I'm wondering is... if you could you avoid a sudden and catastrophic failure of the stuff in the extremes of the racing environment. I mean, if cracking started... well, you probably quit.
I think Bob McKee was sponsored by a stainless steel producer back in the day and built more than one race cars out of the stuff. I wish I remembered if his A-Arms were SS, or just the chassis. Does anyone remember that McKee project by chance?
I haven't seen that many wishbone failures, but the ones I've seen failed either in buckling near the center or at the end fittings. It's hard to predict exact loading in a crash, but I'm not sure you necessarily want material with higher strength, especially if it comes at the expense of ductility.
We've been using 4130N streamline tubing from Dillsburg. I've been dealing with Charles Vogelsong for almost 20 years, and his quirks aside, I've never previously had any issues with quality. We bought a few hundred feet of streamline tubing from him recently, and did find one defective section. I understand he's selling out his inventory and closing up shop, maybe we are getting to the bottom of the barrel?
Even with true 4130 streamline, the tubing material averages only about 15% of our cost to make a wishbone, so it hasn't been a priority, but at some point I'm going to look into alternatives.
I wouldn't use stainless for wishbones.
Nathan
How much money are you really going to save to build something that would be pretty ****ing scary?
Use the squished round tube like Stohr does(or did, I haven't looked lately) and Swift did if you want to save money.
This is one of the reasons that building a car is always more expensive than buying one.
I dunno, maybe not so scary, Wren ---
This is from an article about the McKee F/A5000 car I remembered. The car is still running -- and apparantly cracklessly! Wonder what the wall thicknesses were on the SS a-arms...
This car and McKee Mk8 before it were essentially sponsored by Armco. The frames and most of the suspension components of these cars were constructed of Armco's Grade 304 stainless steel tubing, with TIG welded joints. In this time period, Armco was developing some very high strength stainless alloys. They provided all the stainless steel McKee Engineering could use - for free - and they encouraged experimentation.
McKee used stainless for many, many parts. For example, the balljoint standoffs on Mk12 front spindle were made from "17-4 PH" stainless. Also known as Grade 630, this is a very high tensile strength stainless with the composition of 17% chromium, 4% nickel, 4% copper and 0.3% niobium. The PH designation stands for "precipitation hardening." Its properties can be improved by a single, fairly low temperature heat treatment which causes no distortion of the component. Hub carrier bottom pivots were "13-8 Mo", which is another machineable and precipitation hardenable stainless steel. Its composition is 13% chromium, 8% nickel, 2% molybdenum. This is another high strength material, chosen because of its particularly high toughness and crack resistance.
http://www.britishracecar.com/PaulDu...cKee-Mk12c.htm
There are other articles online about the McKee stainless steel race car adventures; apparently they worked out pretty well. Are we neglecting a potentially very usable material?
Chris
Last edited by Christopher Crowe; 11.29.11 at 1:17 PM. Reason: typical bonehead spelling
Chris - build them out of round 4130 tube then. Initially cheaper upfront cost, and you can later use them as spares for when you do something else. Get the car out!
You can also cut cheaper (very thin) round tube in half lengthwise then bend each half to form an ellipse - then tack weld to the the A-Arms.
And you can use Nathan's aluminum track rods.
EDGE Engineering
I remember seeing a post by Gary Hickman of EDGE Engineering that said he had found a way to flatten round tubing for a-arms. He is in San Diego.
Stainless is very useful in certain applications. We use 304 stainless for exhaust parts and heat shields, but unless you need high temperature performance there is usually a better material choice. In most race car applications you don't care about ultimate tensile strength as much as yield strength, and the 300 series stainless steels have a very low yield point (as low as 200 MPa if annealed, about 40% of the UTS).
17-4 stainless is a totally different story. It machines very nicely "half hard" (H1150) with proper tooling, so you can get a finished part that doesn't need plating with excellent mechanical properties. It is expensive, though, so it's hard to justify for bigger parts.
4130 is really an ideal material for wishbones, where we are more concerned with the performance of the entire weldment, not just the tubing itself. Mild steel is just fine as well. If material cost is a big concern, why don't you talk to Jay Novak and see if he can supply you squashed mild steel tubing?
Nathan
Guys ---
Of course you're right, both of you are, and Rob, you're profoundly deeply completely right, time to get the car out!
Just an interesting academic question for me, really, but I believe I'll be using Novak/Pontiek tubing and some bit-the-bullet streamlined tube (on the front) from Spruce, Chassis Shop or AED.
But PS, elliptical SS is absolutely gorgeous and I wish we were assured that it worked. Some prices are very good in that the stuff is used like mad in the architectural world. Or, you could get an outfit like Armco to sponsor you, just like McKee did!
Thanks guys.
Chris
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