steering wheel shaft threaded, safe to cut new thead?

[chinwaa]

Hi,

In a fit of genius, I've somehow managed to strip the thread of the nut (and the shaft) that holds the steering wheel on the splines. My mechanic raised the possibility of cutting a new thread on the shaft but is worried it will weaken it. Any thoughts please? Should I try to persuade him into it, or look for a replacement?

If I go for a replacement, do I need a whole steering column assembly, or is it possible to find just the central shaft?

Thanks for any advice.

Matt

[scanner]

Cutting a new thread on something the size of the usual steering column shouldn't be any cause for worry.
The nut & thread is only there to hold the steering wheel on the splines, so if the splines aren't damaged I don't think there should be any problem.

[The Great Pretender]

Are you sure the thread has stripped off both? If the nut has stripped it has probably left its metal in the shaft threads. If so it should be easy to clean up the threads with a die.
Cutting a new thread on the shaft is not a problem but unless the diameter is within close tolerance of an alternative thread it will need removing and turning in a lathe to the required diameter, so a machine shop not a garage are the people you need.
If what I'm saying sounds like a foreign language PM me Matt.

[chinwaa]

Hi, Yes it sounds like the shaft threads were stripped as well (or were damaged cutting the nut off). I haven't seen it, but my mechanic says it wasn't possible to cut a new thread as it is. He is indeed taking it to a machine shop with the idea to build it up with some weld, lathe it back to a sensible shape, then cut another thread.

Thanks for your input folks, I'm mildly optimistic this might get sorted without having to fit a new shaft. Just wish I knew how I managed to knacker the thread in the first place!

[briwy]

I think you need to be careful here. This is a critical part that you are changing.

Whilst building up with weld will get the diameter back so that it can be machined and have anew thread cut it may also heat treat the shaft. This may or may not matter depending on the material but I think it's worth noting.

Also, when they cut the new thread try to ensure that it is slightly undercut at the bottom. (bit difficult to explain but a small groove in the shaft at the bottom of where the thread finishes)
Sharp corners can induce stress points and lead to fractures.

Sorry to sound a bit negative but better safe than sorry.

[chinwaa]

Ok, good points, thank you. I shall be sure to pass these on to the machine shop and mechanic.