Window frame bolt thread

I want to chase the threads on the two bolts that secure the window frame to the door on my IIa. Does anyone know what that thread is, is it Whitworth?

Thanks,
Ed

According to RN, the thread is 7/16" UNF.

Item #30 here: https://www.roversnorth.com/category...i_doors_hinges

Quote:

---

Originally Posted by jp-

According to RN, the thread is 7/16" UNF.

Item #30 here: https://www.roversnorth.com/category...i_doors_hinges

---

Great thanks.