Erv, your days are long now. You get up early, fight traffic, work all day, come home and have an evening. When you retire you will find the days fly by, and assuming the honey-do list isn't too long, you may even get out to shoot for a couple of hours. Then the sun goes down and you question where the day went.
As for the 1/4" - 20 TPI - that is standard, but the length of the screw is not. I have run into that several times. Nylon washers are a great invention as a spacer.
Dblunt76 is correct. 1/4 inch, 20 threads per inch. (At least for every camera that I've owned.)
I built a mono-pod myself, using 1-1/4 inch diameter doweling, a threaded insert, a 1/4-20 setscrew, and a rubber washer.
Nice job, I've considered one like that myself, no real need though as I have a metal hiking stick with a 1/4 20 stud and a standard mono pod, but my creative self keeps saying "do one", Bob.