-Good luck!
AFAIK, a single-point 112 TPI threading tool would need a 1,29 thou (32,7 microns) tip radius and a 5,48 thou (0,139 mm) DOC,
but merely choosing the right tool alloy to make that tip strong enough for 303 SS is beyond my knowledge horizon.
Then, DIY-ing a tool grinder for that geometry and checking its precision would be quite an undertaking...
Then making a durable tap is a whole different job.