Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

I have some metric Craftsman ignition wrench sets that I have been happy with... they came in my larger sets. Sizes included:  4,  4.5,  5,  5.5,  6,  7,  8,  9,  10, 11 mm

If those are small enough, look for an older set in this style bag that says Made in USA on the front:







This style bag is a newer set and most often made in China







Any smaller and you may consider a nut driver set like this (2.5 to 6mm range):