This is why I won't trust my life to a cast axle....who knows if it may be one from the last pour or some other quality control problem? I won't chance it. My axle is a gennie 32 heavy forging [dropped] that's been magnafluxed before I drilled it and had it jet-hot coated. I love the look of a chrome axle but hydrogen embrittlement rears it's ugly head with chrome. Yeah, I'm running split bones.
Just a guess, but I think some of it may have to do with the wheels being turned at much higher angles when driven at low speed. That puts just that last bit of stress on the part and it snaps off. A coworker's kid broke two ball joints on his Stratus in parking lots. Also, those horrid modern driveways with the deep drainage curbs at the edge can really stress parts when driving over them every day. The '85 Chevy I used to have snapped its sway bar link on one side doing just that.
I've tried to follow two current threads dealing with broken cast axles (I have an old Superbell cast 4" drop, and I'm starting to worry). There has been a lot of good technical discussion so far far, so maybe someone can enlighten me. An axle is forged because: 1. It becomes stronger due to the forging process - grain is improved, effect of heat treating? 2. It is a more practical, cheaper, faster way to form a complex shape? 3. Other? 4. When a forged axle is heated hot enough to allow it be dropped (stretched), does this negate or change the strength or character of the axle. I've seen the twisted original Henry axle, but has anyone twisted a heated and dropped original axle? 5. Is it fair to assume that a new axle that is forged initially to the drop configuration, then machined and heat treated would be superior in strength to a heated and stretched original forged axle. I'm thinking it may be time for a forged axle. If all things are equal, a dropped heavy '32 would be my choice.
Understandable! The good news is that there are some relatively easy non destructive metallurgical inspections that can be done to ensure the axle is SG grade iron. We're currently looking at a way to offer this as a service to rodders here in NZ.
Correct. These axles were almost 'destined' to snap at some point, it just needs a load beyond the yield of the grey cast iron. The low speed turning loads are much higher than high speed turning loads, and I'm guessing the 'bump' loads are handled slightly better through the shape of the I beam meaning they don't seem to snap on the first little bump in the road.
Hey Justin.... we're recommending you for a knighthood in the next honours list. The White Knight of the South.... bwahahahahahhahha.... Seriously, this is good stuff and may save someone's sorry arse! Glad I bought a CE now!
Castings are cheaper to make. Forgings require expensive tools and machinery, and involve higher labor costs. A good casting, made with the right alloy, can be adequate for the job. A good Forging is tougher, and will bend before they break.
That's the whole idea.... By the way, thanks a bunch to everybody for their input on this - good discussion, from a lot of knowledgeable people. We'll be putting together an information sheet which will provide some guidance to rodders here in NZ, but no doubt it'll be helpful to everyone who has a cast axle. Justin
Yes - it was purchased through Superbell. I know, seems strange, but it is understandable; Superbell don't do an axle for that application so supplied the NZ based rod shop with a Magnum instead.
Well SHIT! I was always planning to use a dropped Ford axle, Wish I'd already ordered mine, cause it looks like the price is gonna go up!
I don't have a dog in this hunt, my axle is tube. Having said that, Why did Ford only have a tube for a short while? Why don't you guys run tubes? Is it ascetics? Or is there some engineering reason? The tube axle under my car went through absolute hell on the dragstrip, countless wheelstands, disc brakes, etc. etc. and it is still straight, and in one piece. And that was with wishbones. I guess I'm hijacking here, but I'm thinking it's pertinent to the discussion. Hope so anyway. Mike
My understanding is that the tube axle will not twist like a forged axle esp with split bones, the lack of twist ability will cuase it to crack...however guys have had them on everyhgting and anything and with all kinds of radius rods etc...
Never heard of an original "Henry" axel doing that.....They usually bend ,.... And they said to bend it back, NO heat... Anyone actually done that ? 4TTRUK
I don't mean to start a riff, but any component or hardware component is subject to failure. Follow the link and read carefully post #74. http://www.jalopyjournal.com/forum/showthread.php?t=306427&highlight=anglia+wreck&page=4 I think the problem here is poor quality, common to off shore casting and manufacturing to enable undercutting market pricing. We're confronted by it in ag equipment darn near daily. I still agree, tube axles are tough and my choice as well, but they still can fail. Bottom line: Magnaflux was invented for the purposes presented here.
I could be wrong - it's happened before-, but I don't think the Magnaflux process can detect a flaw based on the iron being an incorrect alloy. The problem with the broken cast axles shown here seems to be that the grade of cast iron is not as specified. The Magnaflux process works on the basis that a crack disrupts the continuity of the magnetic field induced in the part. Just because the axle is cast with the incorrect grade of alloy doesn't mean it's cracked at time of testing. Maybe if you tested it in between the instant of cracking and catastrophic failure a crack could be detected, but what are the odds of that happening? Bob
hey hot rod kiwi this is Broken super bell axle Luis i did talking to you in me post a couple of days ago but Ryan the moderator took it of with no explanation, i would like to know if i did something wrong by making every one aware of the problem. BROKEN SUPER BELL AXLE LUIS
The Safety Factor used when engineering suspension components is supposed to be at least 10x. Which means you should be able to hit a BIG bump, without breaking anything. Bend ? Maybe. Break ? NO.
Magnaflux identifies surface cracks, before the component fails completely. http://en.wikipedia.org/wiki/Magnaflux It does not identify the wrong alloy for an application.
I dont think he deleted it, but closed it once it had run its course. I can still see the thread. It is an important subject, and the lab results posted on this thread make it absolutely clear that there is a serious quality control issue here that must be addressed.
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