Welding a steering shaft

[stownsen914]

Hi all,

I am doing some suspension and steering customizations to that require adding a universal joint in place of the rubber donut that connects the early 911 / 914 lower steering shaft to the steering rack. This means welding some splined stubs to the lower steering shaft.

Any tips for welding to the lower steering shaft? Tips?

Thanks in advance!

Scott

[ClickClickBoom]

TIG!
Did it on my diesel Landcruiser powersteering conversion.

[Dan J]

Get a pro welder to do it (like Mr CCB above)

[stownsen914]

I should have mentioned ... I will certainly be having a pro welder do this, and it will be TIG'd.

I am wondering if anyone happens to know what steel these shafts are made of - low carbon steel? It will help the welder know what rod to use. Also, it it's made of high carbon steel like chromoly, I'd be inclined to have the part stress relieved at a heat treatment facility after welding. I don't want my steering shaft to fail while in use!

[Targalid]

This is a typical repair done on drive shafts that lose the splines. The old splined portion is removed and a new splined end is welded in place. The welder has a rotating holder, not unlike a lathe, that keeps the parts completely in line. If you have a drive line shop locally you can either watch how it is done or pay the guy to weld it.

[ClickClickBoom]

Don't worry, relatively low stress application, allow to air cool. With proper beveling the penetration will increased, and the heat affected zone will be minimal with TIG. Listen to your welder, he will advise. Don't overthink this....

[Rob T.]

I would not weld a steering shaft until i exactly know which steel the shaft is made of.
Some sorts (specially the strong sorts) are not easy to weld, or you can't weld them at all.
They tend to get little cracks....
It depends on the right welding rod any many other parameters.
just want to say that...

[stownsen914]

Originally Posted by Rob T.

I would not weld a steering shaft until i exactly know which steel the shaft is made of.
Some sorts (specially the strong sorts) are not easy to weld, or you can't weld them at all.
They tend to get little cracks....
It depends on the right welding rod any many other parameters.
just want to say that...

Thank you for that information. How would I be able to tell what steel it's made from?

[ClickClickBoom]

Originally Posted by stownsen914

Thank you for that information. How would I be able to tell what steel it's made from?

Your welder will do a spark test, as I said if he gets a good weld it will work fine. This is as close to a no stress appication, torque transmission via human abilities to produce said torque means virtually no stress. But don't, mind me, I only have 6G certification in multiple processes, TIG(35 years) and MIG included with formal training......you and many others are over thinking this.

[Rob T.]

I have no idea.
Maybe it is a "normal" steel that you can weld without any problems.
It could also be a steel with high share of carbon which aren't easy to handle.
Just wanted that you think about these problems...

[Rob T.]

Originally Posted by ClickClickBoom

Your welder will do a spark test, as I said if he gets a good weld it will work fine. This is as close to a no stress appication, torque transmission via human abilities to produce said torque means virtually no stress. But don't, mind me, I only have 6G certification in multiple processes, TIG(35 years) and MIG included with formal training......you and many others are over thinking this.

Sounds like you are a welding pro.
Then it is certainly no problem to weld the shaft.

[stownsen914]

Originally Posted by Rob T.

I have no idea.
Maybe it is a "normal" steel that you can weld without any problems.
It could also be a steel with high share of carbon which aren't easy to handle.
Just wanted that you think about these problems...

Thanks. I was thinking that in the absence of more information about what steel it is, to treat it as high carbon steel. I.e. have the welder do pre and post heat, and then have the welded part stress relieved afterward.

[stownsen914]

Originally Posted by ClickClickBoom

Your welder will do a spark test, as I said if he gets a good weld it will work fine. This is as close to a no stress appication, torque transmission via human abilities to produce said torque means virtually no stress. But don't, mind me, I only have 6G certification in multiple processes, TIG(35 years) and MIG included with formal training......you and many others are over thinking this.

Ha, fair points, and thank you for the information. Agreed that torque on the part is minimal compared to other applications. I just get nervous at any remote chance of failure of steering!

I can keep the discarded portion of the shaft for the welder to practice with. I had a suggestion to join the shafts using a rosette weld, I assume to increase the surface area of the over which the shafts are welded. Is this overkill?

Also, I think I missed your earlier post before commenting on the pre/post heat and stress relieving. It sounds like you don't find those needed in this case.

[ClickClickBoom]

This is classic over thinking. Think exactly what a steering shaft is being used for, torque transmission, human powered. By process of deduction, why would the good Dr. use an exotic material to transmit torque that in almost every possible scenario would be less than 60 Lb Ft on the worst day? If nothing else give the Pcar engineers credit for using the proper material for the job, cold rolled steel rod would exceed every possible human force applied at a price point acceptable to the bean counters. And remember the steering shaft is a potential harpoon in an accident, short but still in line with your sternum.
The elegance in Pcars isn't materials, its pure engineering excellence.

[Rob T.]

Originally Posted by ClickClickBoom

This is classic over thinking. Think exactly what a steering shaft is being used for, torque transmission, human powered. By process of deduction, why would the good Dr. use an exotic material to transmit torque that in almost every possible scenario would be less than 60 Lb Ft on the worst day? If nothing else give the Pcar engineers credit for using the proper material for the job, cold rolled steel rod would exceed every possible human force applied at a price point acceptable to the bean counters. And remember the steering shaft is a potential harpoon in an accident, short but still in line with your sternum.
The elegance in Pcars isn't materials, its pure engineering excellence.

sounds plausible....

[ClickClickBoom]

Originally Posted by stownsen914

Ha, fair points, and thank you for the information. Agreed that torque on the part is minimal compared to other applications. I just get nervous at any remote chance of failure of steering!

I can keep the discarded portion of the shaft for the welder to practice with. I had a suggestion to join the shafts using a rosette weld, I assume to increase the surface area of the over which the shafts are welded. Is this overkill?

I turned a male reduced section on one side and a corresponding female section on the other end, beveled and welded. Have done dozens of similar steering shafts from 32 Fords to my Diesel Landcruiser. The turning was more for alignment to simplify the welding setup than anything else.

[stownsen914]

Originally Posted by ClickClickBoom

This is classic over thinking. Think exactly what a steering shaft is being used for, torque transmission, human powered. By process of deduction, why would the good Dr. use an exotic material to transmit torque that in almost every possible scenario would be less than 60 Lb Ft on the worst day? If nothing else give the Pcar engineers credit for using the proper material for the job, cold rolled steel rod would exceed every possible human force applied at a price point acceptable to the bean counters. And remember the steering shaft is a potential harpoon in an accident, short but still in line with your sternum.
The elegance in Pcars isn't materials, its pure engineering excellence.

Fair points again. And I'm smiling a little as I read ... It makes sense that Porsche would have used plain old mild steel for this part. Thanks for your thoughts on this.

[Porboynz]

All good points, but how do you explain the wheel nuts ?????

[rocket534]

All good points in this conversation, A short reminder or 2 about welding Borgeson style universals in steering shafts.
1.] Don't run your grounding through the U-Joint.
2.] Keep the U-joint as cool as possible while welding the female ends of it to the shaft, I use rags soaked in ice water and wrap the joint with them..I usually weld about 1/3 of the way around the juncture and then allow the U-joint to air cool until you can touch it before welding the next 1/3.
I've done many of them on street and race applications and never had a failure.

[stownsen914]

Thanks for the comments. Note that I won't be having the U joint itself welded to the steering shaft. I bought two short Borgeson splined shafts that will be welded to the 914 steering shaft, so the Borgeson U joint will just slide on and be secured the normal way.

Originally Posted by rocket534

All good points in this conversation, A short reminder or 2 about welding Borgeson style universals in steering shafts.
1.] Don't run your grounding through the U-Joint.
2.] Keep the U-joint as cool as possible while welding the female ends of it to the shaft, I use rags soaked in ice water and wrap the joint with them..I usually weld about 1/3 of the way around the juncture and then allow the U-joint to air cool until you can touch it before welding the next 1/3.
I've done many of them on street and race applications and never had a failure.