Master Alex,
If your Ace store doesn't have it, any LHS will have it in the Dubro section.
Also, one of the questions you asked was "What's the secret code here?". Here's the secret code so you can figure any number size thread.
First of all, numbered thread sizes are below 1/4" dia and go up to about #14, although I've never used any above #10.
The code is : ( and don't tell anyone, because it's a trade secret!!) As you know the second number is the number of threads per inch. The mysterious first number is the outside diamater fo the thread. To figure the diamater, in thousanths of an inch, you multiply the first number (in your case: 4) times .013" and then add .060" to that number.
So... 4 X .013" = .052". Add to that .060" and you get .112" dia as EloyM mentioned. This works for all the number size threads.
...Steve