Good luck with the die! If you have any way to cut these threads on your lathe, do it!
Titanium work hardens 'like a bitch' and tapping is a strange mix of cutting and extrusion.
I had to make some 1/8 BSP lambda sensor plugs/bosses and only have a metric lead screw. The plugs were M10 race bolts turned down and I managed to hold the die stock in a vise and use a long breaker bar to turn the bolts... only just... it was seriously hard work after the first turn, despite cutting fluid everywhere.
I looked for a spiral tap designed for stainless etc. to do the bosses but the price as stupid. I ended up grinding down a second cut tap with a Dremel, to reduce the lands and enlarge the flutes, which reduced the friction enough for me to blast through with the tap in an 18V drill. Turning down the bosses with a carbide tool was child's play by comparison.
