I would like to start making kitless pens like Mr. Fred Brunings but don't know the thread size for the Classic Fountain Pen from Penn State, or where to get the correct size die. I'm based in Ontario, Canada.
If you want to start with ready made sections. The churchill replacement sections from William Woodwrite, over in Guelph, uses a standard 10x1.0 mm thread.
I have one of these sitting in the shop, so i did a quick check for you.
I drilled a piece of acrylic with a T sized drill bit. Then I tapped it using an 10x1.0 tap from my generic Canadian Tire bit set. I then had to drill a little recess to fully seat the section, using an X drill bit.
As you can see in the attached pics, it worked well.
You wont need the die to use their front section with feed and nib. It is more than likely 8.5 x 1 But without having one to measure Im just guessing from what is normal for that size pen and tubes. You will only need a tap to make the threads it screws into.