Diy - fail

[JohnUlaszek]

Jim,
I agree, rag joints work fine.



You mentioned seeing wear on jack shaft assemblies -- what was the application and input loads?

What do you think the loads are on a rag joint?

[Jim Nilsen]

Jim,
I agree, rag joints work fine.

You mentioned seeing wear on jack shaft assemblies -- what was the application and input loads?

What do you think the loads are on a rag joint?

I have worked with them on packaging machines that had very low torque to turntables that rotated up to 600 lb to 900 lb of magnet wire all day long to load up drums. It doesn't seem to make a difference on the load sometimes because the pins or bolts will work the holes larger from the flex and the torque of the drive motor is what wears them not the resistance of the load, when more room is wanted for clearance of movement it just happens. Once you get them worn in you can go back and make timing adjustments on the machines if needed like inthe packaging machines and the turntables only went one direction and indexing was not really an issue. I see nothing but the same slop he is trying to fix coming back within hours of use.

The load on a rag joint is probably not a lot with power steering until you hit large bumps or impacts and that is why a rag joint is there to begin with and are easily and cheaply replaced by design. he spent more on JB weld and grade 8 fasteners than he more than likely would have spent on a new rag joint.

[JohnUlaszek]

The load on a rag joint is probably not a lot with power steering until you hit large bumps or impacts and that is why a rag joint is there to begin with and are easily and cheaply replaced by design.

I tend to agree, the largest input I can think of is that of the strongest person you can find, turning the steering wheel to full lock as hard as they can -- any misalignment could create additional stress in the entire assembly which may result in binding.

Given our friend has modified the bolted joint by eliminating two of the shoulder bolts, I am not quite sure how it would behave compared to stock in the event the isolating material fails. In stock configuration the joint is designed to continue working even if the isolating material (rubber) disintegrates, which it tends to do on 40 year old cars.

Regarding True's thoughts on work hardening, work hardening is a result of repeated plastic deformation as a result of loads being greater than the yield but less than ultimate tensile. I think the disc would begin to delaminate before any failure of the aluminum. If the bolted joint was maintained in OEM configuration, with the exception of the new disc, it could result in a loss of clamp load in the joint manifesting itself in sloppy steering; given the change in bolted joint design, the fasteners and the design of the joint should be scrutinized.

I certainly don't endorse this guy's efforts, but it is an interesting engineering problem.

[406 Q-ship]

The issue I have with this that isn't being addressed, he is checking the out of alignment at a static turning of the steering wheel. Well in a corner loading situation the chassis will be under deflextion and moving in directions that the orginal rag joint can compensate but that a solid or his goofy laminate can not do. What if in a high corner load he needs to adjust steering input and the steering shaft is in bind and will not move or requires a high amount of force, it could cause a major over turn in or over correction and loss of vehicle control. I have worked on the Fox and SN95 Mustangs and those chassis move all over the place, this is not safe in my opinion. Someplaces just are not worth looking to cheap out and this is one of them.