If you see the file I attached, it helps explain
The cylinder has a recess that is 6mm deep and it's made from aluminum. There is a part that goes into the bottom of that recess and is 2mm high, leaving 4mm space above.
That plug that's sort of mushroom shaped - the top part is the same OD as the cylinder and the bottom smaller OD part will screw in.
I don't have a ton of room to work with (4mm of thread area). I can use any thread I want, but i want to get the thread as close to the shoulder in the plug part as possible. The cylinder recess is 6mm deep, and I can overshoot the thread to ensure the entire first 4mm is threaded completely... but I can't do that on the top.
If I use my generic 60-degree laydown threading bit on the plug, and cut a fine thread, I am not really going to be able to get all that close to the shoulder.. I am not at work right now but I bet I can only get within maybe 2mm of the shoulder with an AG60 threading bit.
I thought I had seen some full form threading inserts that let you go right up to the shoulder - they extended out slightly beyond the end of the toolholder.
Or, if I got a full profile insert made for a fine pitch thread, wouldn't the actual cutting tip triangle be a lot narrower, allowing me to get right up to the shoulder?
Or does anyone have any suggestions on how to do this? I know more threaded area would be ideal, but I am very constrained on the length and dimensions of this part so what I have here is all I got to work with. Any suggestions are welcome