What is the thread for the steering wheel nut.

[Jim Burrill]

I have a sample provided to the machine shop and he isn't getting a match on his tools to the thread.

Does anyone know what the size is supposed to be?
The machinist is thinking it was press formed to the shaft threads, and not milled.

[Phil Waterman]

Hi Jim

Refresh my memory what are you working on? Do you need the nut or retread the shaft?

Cheers Phil

NOW I see that your question is in the CARRIER heading.

[RichardT10829]

Canadian pattern universal carrier steering box nut that holds the steering wheel on, Jim needs the nut, or the correct thread so he can make another.

[Jim Burrill]

Mechanic offered a possible way to check..... embed the thread in a block of plasticene. (Modelling clay) which i happen to have some in the shop.

I will brace the back and impress the front along the threads. That will give him something to neasure.

His tools have BSF and BSW but he said they weren't matching up with the sample nut (original CTL part on loan) nor SAE or Metric.

For BSF, he said it should be 55 degree pitch, and it doesn't match that.

Have I stumbled across some odd thread only used to trap the steering wheel on the shaft? I really doubt that - - but odder things have happened!

[Michael R.]

Have you considered BSP ?

[motto]

Originally Posted by Jim Burrill

Have I stumbled across some odd thread only used to trap the steering wheel on the shaft? I really doubt that - - but odder things have happened!

It's quite possible that this comment is closer than you think Jim.
I haven't checked it out completely but the nut that holds the steering wheel on the Chev CMP seems to be an oddity and I believe to be the same as the CCKW which appears to be the same as Dodge WC and I think M37 and who knows how many others. These are tubular shafts but I would imagine the U/C had a solid shaft. However:
To approach the question from a different angle perhaps you could give a description of the original example in your possession and see if it compares with anything else out there.

David

[brengunman]

Just checked my Canadian built Mk II. It appears to be standard 3/4 - 16 NF with 60 degree threads. The manuals show that there is a different steering box for British units.
George

[Lynn Eades]

I think all 3 steering boxes (Canadian, Brit, and Australian) all take the same nut.

[Chris Suslowicz]

Originally Posted by Michael R.

Have you considered BSP ?

Or National Pipe Thread (U.S. NPT), because 16tpi and 60 degree threadform seems to match that exactly:

http://www.engineeringtoolbox.com/np...ads-d_750.html

[Stew Robertson]

Pipe thread is tapered
The thread in the nut can be turned on a lathe then the cap tig welded on to match the under cut in the nut
clean up, the welds and presto you have a steering wheel nut almost original
or maybe it is
the cap is a piece of light gauge metal like a frost plug

[Lynn Eades]

3/4 NPT is only 14 tpi. It will be 3/4 U.N.F. (16 tpi)
When quoting U.N.F. or U.N.C. it is not required to quote the inclusive angle of the thread. They are all 60 degrees while the standard British threads are 55 degrees.

[rob love]

Originally Posted by Stew Robertson

Pipe thread is tapered

Not quite true. NPT (National Pipe Tapered) is tapered, NPS (National Pipe Straight) is straight.

[ajmac]

Standard BSP is a straight thread too, it seals on a copper or dowty washer rather than on the threads like NPT.

[Paul Dutton]

Originally Posted by ajmac

Standard BSP is a straight thread too, it seals on a copper or dowty washer rather than on the threads like NPT.

Or WD seal.

[Stew Robertson]

That is the point I was making pipe thread is Tapered the nut is not and the threads are a standard 29 1/2 degree thread at 16 tpi and can easily be turned on a lathe with the cap tig welded on so the thread can have the under under the cap
Clear as mud

[Stew Robertson]

hi Lynn I was taught from way back when you always set the compound rest at 29 1/2 to cut the standard Canadian thread but Canadians are always a little behind ,but not down under

[Lynn Eades]

Stew, that went straight over the top. I'll have to stand up next time. (the cricket people would say "it went straight through to the keeper")
I do have a small lathe, but powered thread cutting is not something that I can do on it. (I would figure it out if I had to) Obviously my skills in the machine shop, are not up with yours.
I do use it to get the die holder square.

[Jim Burrill]

Got a call from the machine shop. They matched the thread for the sample nut and also the clay impression I made of the spindal.

They say it is a UNF 3/4 16 60 degree.

That matches also what Lynn said.
They are cutting a chunk of steel for me to test fit and then machining the nut and the flange for me.

No idea of cost yet. I need it and they can do it, and I have been happy with the work they did drilling all the holes in the Humber Gun mantle.

SO, I am getting three made up. 1 for my Mk1, another for Lance's Mk2 that I somehow lost, and one spare.

If anyone is interested in the spare, let me know.

[Stew Robertson]

no comment

[Lynn Eades]

Stew!

[Jim Burrill]

Got the replacements from the machine shop. Now I have two spare. (and for sale... see the For Sale section!

[super dave]

Nice job, they turned out great

[Michael R.]

You seldom see the original take-off nut(s) without an apprentice hammer blow depression on the thin dome section.