RE: metal control rod threading tool
A good way to do it is to buy the 4-40 rods threaded on one side and either use a 4-40 size connector (a clevis or ball joint, etc.) on one side and then "die cut" a 2-56 on other side. You can put the larger connector where ever you want. Or just buy fully threaded rod and cut to size and stick em in nyrods or whatever.