Waterjet cut diamonds in my I-beam axle saturday!

That's like saying you once saw a turd flying through the air, so turd shaped airplanes are probably OK.

 

yeah, but those arent sharp cornered diamonds, those are rounded cornered slots.

my exhaust smells like roses.

 

Ummmmmm, right. You broke the code LOL.

 

That looks rad!


All the prior suggestions are spot on. I would use it as a wall hanger instead of using it on a road car. There are too many failure points without rounded edges on your diamonds.

 

its different its cool ive never seen it done in diamond shape before hotrod on man awsome

 

Axle looks very cool. I like the idea of seeing someting different.
However, coming from an aviation engineering background, when it comes to machining, sharp edges are not your friend. At a bare minuinm, I would have the axle shot peened not bead blasted to stress relieve it.
Talk in depth with an SME that specializes in metrology and get their expert advice before moving forward with this cool looking axle.

 

They are! Haven't you seen a Beech Musketeer?

 

I wanted to add this. If you do run that axle let us know what happens over time. Also tell a wife or a friend to let us know if you are not able to. Circles ovals are good. Squares triangle pointy things are bad. Good luck

 

I say run it and do a Dye Penetrant or Mag Particle inspection periodically just to be on the safe side!

 

if you take the wings off a plane it does have a turd shape

 

Everyone that says that the sharp corners are a bad idea is definitely right. However, I would love to see some real engineering on the issue instead of simply a load of conjecture, which is exactly what this is from both sides. Let's see some numbers. When I ran the SAE team at University of Delaware, we'd test suspension components on an Instron machine to get real world figures on when we could expect things to fail. We'd also run CFD analysis on SolidWorks to find areas of stress we hadn't accounted for. Nowhere in this thread do I see any kind of real data for or against, just a lot of "that looks like it will break", or "that looks fine". If there is a safety factor of 15 and the only way the axle will break is if he hits a curb at 40 mph, then the least of his worries is the axle and it's probably fine.

Wouldn't shot-peening increase the strength of the axle and relieve the stress? Something to consider.

 

"Odd-shaped holes weaken a stressed beam" is simply a load of conjecture?

Your degree is from where, again?

 

Why are you attacking him? It doesn't matter whether his degree is from MIT or Chico State. He never said he disagreed with the statement that these holes decrease the fatigue strength of the axle. What he said was that he'd like it if someone calculated the fatigue strength to see if the axle wouldn't break under normal driving conditions, and would only break during a severe collision.

 

Slow down there JD. His corpse isnt going to be very beautiful spread all over the inside of his car when it cartwheels down the highway.

Just make sure you're the one in the lane beside him when it blows. I wouldn't want to get any on my Volvo.

 

Bead blasting is NOT a stress relief method for steel...EVER...shot peening is...don't confuse the two...misinformation is a very bad thing...

 

Looking at this photo for a few minutes I highly doubt this car was built in this 60's.

 

Probably from a better school than where you got yours from judging by your reading comprehension skills. It doesn't take a BA, or a Juris Doctorate (which I'll have in about 6 months btw) to learn that you should get your facts straight before you open your mouth and attack someone. It's a sure fire way to look like a real ass whether you're on an internet message board or in a court of law.

Thanks to Mr. Fahrt for understanding the gist of my post. Again, I'm not taking a position as to whether it's safe or not. I don't know, and without real data, none of us do. Just to clarify, I am not, nor do I claim to be, an engineer. However, I did take enough courses to have at least a rudimentary background in the process and theory. We were taught that a safety factor of 6 is acceptable in the automotive field. I would love to see if anyone has actually tested an I beam axle, whether it be Ford, Chrysler, etc. to see what kinds of loads and forces they can handle.

 

Actually this is photoshop not an actual axle. look at the "cutouts"



The diamonds are a bad idea. I graduated with a degree in Industrial Design, then worked in a firm doing engineering work. Sharp points don't work b/c they're weak! It's plain and simple. Yes you can take material out of an i beam axle but you do need to be careful as to how much. You can lose all integrity if you do.

In my opinion the axle is not an area to fuck with too much or you're risking a lot. It supports the whole weight of your car and worse, the steering. So if you lose it you're endangering your own life and the lives of those around you and that's not a decision to be taken lightly.

To those that have said just run it who cares if it breaks, i'm sure you would feel differently if your loved one was killed by someone that didn't know what they were doing and just went for it. There's dozens of threads on welding and knowing what you're doing when it comes to suspension work. Seems it goes out the window with solid axles for some of you.

 

Shot peening may relieve some of the stress but I would believe that others who have been around for a while feel the same way that I do and that is that the sharp corners of the diamond may increase the chances that a crack "could' start there. It may never happen but there is a lot bigger chance that it would over the odds that one with round or oval holes would crack.

 

Agree 100%. There is no doubt that the edge increases the probability of a crack starting there. The question is simply does that increased risk rise to a level of becoming unsafe.

 

I agree... and judging by this photo the tops of the diamonds are too close to the upper rail creating a higher risk level. Cutting through the thinnest part of the center of the beam as most do with holes doesn't run the stress area directly up to the rail. The whole purpose of the center cross section of an i-beam is the vertical runner is the source of strength, while the horizontals provide shape and support, you remove too much from the strength factor you're in for a bad surprise.

http://www.jalopyjournal.com/forum/attachment.php?attachmentid=886676&d=1264971608


It may not be immediate but it will happen, unfortunately if it's not right away everyone will think it's safe and replicate putting a lot more unsafe vehicles on the road.

 

Those diamonds are not nearly as large as some holes i've seen. If it starts to crack in your lifetime, which it probably won't, do circles around the diamonds. Just keep an eye on it. Looks good though.

 

funny thats Volvo is mentioned so much
They had to take back several thousend
cars from the 140 series and change fans
that cracked beacuse they had to sharp
corners so the owners ended up with
the blades through the hood
and sometimes in the face.
And how much load is it on a fan.
It is vibrations that start cracks in
sharp corners not heavy loads

 

a water jet uses a stream of water about .024" in diameter, so the corners would have a radius of .012".

i know it's small, but maybe it would cut down on the stress.

-danny

 

Thats what I was thinkin. All those sharp junctions.

 

Just gring a radius in the corners.

Just for future reference when I'm going to cut a polygram into anything I always drill a small hole at the corners and cut to the hole. But maybe I'm just paranoid.

 

You can take a stock axle and attach the split bones on each side and flex it with just one man's strenght. Try it sometime. Then add to that weight, forces encountered with the road, bumps, curves, pot holes, etc. It get's alot of twisting. When Henry did his design the front bones were designed to be a wishbone along with a center mounted spring to where everything pivioted inline, The ibeam was never intended to twist as what most guy's do with it today. The only saving grace that axle would have would be to use a 4-link with rubber bushings, not really traditional, but still your looking at stress as in twisting. Since your friend has lot's of equipment set it up in a real world test and let the machine twist it for say a month 24/7 and see what happen's. I'd say that would be close to a life time of driving it, if it's a pleasure driven car. This all takes in to affect that your axle is a quality forged piece? Cheaper quality will fail sooner.

 

no engineer here but have to agree with the rest,those diamonds are well into the arch of the rail.its gonna fail sooner or later,be it on a curb,pothole or stress over time with normal bumps and ruts.how can you enjoy your ride with that in the back of your mind.or selling the car to someone.hate to rain on your parade but you gotta rethink this one.

 

If it starts to crack you're going to lose the integrity of the axle, cutting circles after the fact isn't going to do anything but speed up the process once the crack forms. If it starts to crack the axle is junk and a wall hanger.

 

oh crap!! no pun intended, thats funny stuff, a little chunky and not very aerodynamic, but still funny and I'm not an engineer!