Steering shaft - stripped threads - what size die to recut?

[cattlerepairman]

Not an MV but a 1972 Kenworth cabover. Finally got the steering wheel off, but even after rounds of PB blaster, tapping, and pulling it required so much force that the steering wheel nut stripped the threads at the end of the steering shaft.

The shaft is a smooth 0.82 inches all around now.

What is the die size that will work for that diameter? I was thinking 7/8 - 14 . I don't have any that big so I can't simply hold one to it and check.

My theory is that as long as there is ok thread and a secure nut, it will work
The steering wheel nut only holds the wheel down; the actual force is carried by the splines and they are all unharmed.
If I am overthinking it and I should just go for it, let me know!

 

[simp5782]

They

Not an MV but a 1972 Kenworth cabover. Finally got the steering wheel off, but even after rounds of PB blaster, tapping, and pulling it required so much force that the steering wheel nut stripped the threads at the end of the steering shaft.

The shaft is a smooth 0.82 inches all around now.

What is the die size that will work for that diameter? I was thinking 7/8 - 14 . I don't have any that big so I can't simply hold one to it and check.

My theory is that as long as there is ok thread and a secure nut, it will work
The steering wheel nut only holds the wheel down; the actual force is carried by the splines and they are all unharmed.
If I am overthinking it and I should just go for it, let me know!

Splines are generally 1inch with the nut being a 7/8 on kenworths and freightliners

 

[silverstate55]

OR, get a new nut slightly smaller & accompanying die and go from there.

(Since you mentioned that the previous threads were stripped out and left a smooth shaft…why not just cut new threads slightly smaller and use a new nut that fits them? With a little anti-seize applied of course…)

 

[cattlerepairman]

@silverstate55 Yes, that is essentially what I am asking; I am just not sure which die size to go for with what is essentially a 0.82 inch rod to cut threads into.

 

[simp5782]

@silverstate55 Yes, that is essentially what I am asking; I am just not sure which die size to go for with what is essentially a 0.82 inch rod to cut threads into.

13/16 is .813

 

[silverstate55]

@silverstate55 Yes, that is essentially what I am asking; I am just not sure which die size to go for with what is essentially a 0.82 inch rod to cut threads into.

My apologies; I must have misread or misunderstood…didn’t meant to derail your thread.

 

[Welder1]

Not an MV but a 1972 Kenworth cabover. Finally got the steering wheel off, but even after rounds of PB blaster, tapping, and pulling it required so much force that the steering wheel nut stripped the threads at the end of the steering shaft.

The shaft is a smooth 0.82 inches all around now.

What is the die size that will work for that diameter? I was thinking 7/8 - 14 . I don't have any that big so I can't simply hold one to it and check.

My theory is that as long as there is ok thread and a secure nut, it will work
The steering wheel nut only holds the wheel down; the actual force is carried by the splines and they are all unharmed.
If I am overthinking it and I should just go for it, let me know!

At .820" diameter the closest thread would be metric at 20MM. You should be able to cut a M20 thread on that.

 

[cattlerepairman]

Thank you all! I ended up with 7/8-14 and it worked fine the first go. @Welder1 I did not consider metric (because the truck is not, but that would have been another way to go, for sure)

- although the closest, the 13/16 die is non-regular and hard to come by (I found a place that has it)
- 11/32 NUTS are next to impossible to find; I could not locate any, so abandoned that thread size. Thank you for confirming the size, @silverstate55
- ended up being able to rent the 7/8 die (it is $200 to buy) but the guy did not have a holder for a 2" die
- found a machine shop that let me borrow the holder

All in all, 4 hours of driving around and going places to gather the tools to do an essentially 5 minute job of cutting new threads. I paid my "stupid tax" in full and feel rehabilitated!

Again, thanks all for your suggestions!

 

[MarkM]

What was it before coarse or fine threads?

Only reason why I ask is fine threads are much stronger.

Mark

 

[cattlerepairman]

@MarkM
Yes, it was SAE fine thread. I looked at it but the nut really only holds the steering wheel down so it does not slip off the splines. I doubt that the coarse thread really makes a difference. The truck is a cabover, so the steering wheel is almost horizontal!