A couple questions for the pros.

[George Willer]

Most are NC. Other that some holding the rear light holder which I'm not sure are original, the only S.A.E. threads I can think of are holding the flywheel.

Well now I'll think of some more... Steering wheel nut, manifold studs, adjusting clevises on brake rods and governor rod, steering rods, bolts on center steering lever, wheel rim bolts, seat bracket key, bolts holding seat pan, wheel lug bolts, ...............Wow!

In general, all fasteners in threaded holes in cast iron will be NC.

[kylev]

And what does NC stand for?
What are the other types. I thought there was only SAE and MEtric

[Donny M]

National Course, of course

[Jim Becker]

Here is a more detailed explanation:
http://www.sizes.com/tools/thread_screw.htm
With some more here:
http://www.gizmology.net/nutsbolts.htm

By the way, there is a lot of other neat stuff on the second site I mentioned.

[beaconlight]

There are number sizes and fractional sizes. In general number sizes are for smaller bolts. NC = National Course. NF = National Fine. As an example a number 10 24 is course and 10 32 is fine. The 24 and 32 = the number of threads per inch. There are a couple of cross over points. !/4 and numbers size 14 are the same size but named differently.
Ihope this makes it clearer.

Bill

[Patbretagne]

Thanks again guys
So in general one is looking at NC and NF
Which in UK would be ANF and ANC
will do a bit of sherlock to see where WE stand Yaume isolated in the wilds of Brittany!!!
Pat

[johnbron]

In general, all fasteners in threaded holes in cast iron will be NC.

Now that I read that statement By`George it got me to wondering about the 2 bottom holes in the dog-legs which screw into cast iron. They seem to be different sizes in my 2 Cubs, some NF & some NC so they must have been re-tapped?. In fact one hole has a broken easy~out that I gave up on trying to remove.

[George Willer]

In general, all fasteners in threaded holes in cast iron will be NC.

Now that I read that statement By`George it got me to wondering about the 2 bottom holes in the dog-legs which screw into cast iron. They seem to be different sizes in my 2 Cubs, some NF & some NC so they must have been re-tapped?. In fact one hole has a broken easy~out that I gave up on trying to remove.

Bronson,

The Cub I'm working on now has 10-24 on the right side and 1/4-20 on the left. Now that I think about it a little, I think 1/4-20 makes a lot more sense and I may change the right side. IH never did it that way, but it seems silly to expect the 10-24s on the bottom to carry the same load as the 1/4-20s on top. No wonder so many of the 10-24s fail!

I don't worry very much what the correct police think.

[Jim Becker]

I thought all 4 were the same. My parts books show 10-24. All they have to hold is the panel, which also holds the grille.

That is at least until the bracket that holds the hood to the radiator side channels breaks off, then it has to hold the hood. I suspect that is when the side panel screws start breaking.