Steering Column Thread Pitch?

[AirmanPika]

Well too my horror my threads have stripped on the steering column of my Series III as I was trying to reinstall the steering wheel. I didn't realize things were bad till it was too late. That said, the remaining undamaged threads look to be for a 3/4-16 nut but I wanted to see if anyone knew for sure. I could use a split die to grip the good threads and work in reverse.

[cedryck]

Yikes when did that happen when you took the nut off or was the nut on there with the threads in that condition. I am curious what you are planning to do? Are you going to chase the threads and try to clean them up, or replace the shaft. I am considering changing my 2a steering wheel to a later style three prong, and have just finished collecting one from a friend. Cheers.

[SafeAirOne]

I don't have Machinery's Handbook with me, but the one that used to be on my '73 SIII appears to be 11/16-28 UN 2A based on the following:

Measured major diameter of mine: 0.684", 28 threads per inch.

The specs for the 11/16-28 UN 2A thread major diameter: 0.6799 to 0.6864 and, of course, 28tpi.

I'm willing to bet that this particular die isn't in any common tap and die sets, but I guess $40 is better than a whole new column: http://www.mscdirect.com/browse/tn/T...027+4288129900

[JimCT]

thread file

you can clean that up with a thread file or triangular file, just go slow and be careful

I don't have Machinery's Handbook with me, but the one that used to be on my '73 SIII appears to be 11/16-28 UN 2A based on the following:

Measured major diameter of mine: 0.684", 28 threads per inch.

The specs for the 11/16-28 UN 2A thread major diameter: 0.6799 to 0.6864 and, of course, 28tpi.

I'm willing to bet that this particular die isn't in any common tap and die sets, but I guess $40 is better than a whole new column: http://www.mscdirect.com/browse/tn/T...027+4288129900

[SafeAirOne]

you can clean that up with a thread file or triangular file, just go slow and be careful

Ha!...I think he's beyond the "clean up with a file" stage. His is the FIRST picture in this thread.

The one you referenced has a knackered ballscrew on the OTHER end, inside the box.

I just threw the pic of mine up there to make sure the thread spacing looked the same because the OP was saying it might be 16tpi which is vastly different (visually) than 28tpi. Kind of a sanity check to make sure these weren't 2 completely different threads.




It occurs to me that a 11/16-28 UN 2A FORMING die might be better than the CUTTING die I linked to for this repair job.

[AirmanPika]

Well I decided the existing threads were too far gone so I decided to step down a notch and get some solid new threads. I used an M18-1.5 die to cut new ones and it worked like a charm. It was just enough to cut solid threads without impacting shaft diameter at the threaded portion. I prolly would have been better off with a finer thread pitch than I used but with some thread lock and the actual lock washer I should be OK.