TimC - don't be silly. If there's something we learned in this hobby is that we can never have enough nuts and bolts! Anyway, these Hirobo lock nuts (with this extra metal blades instead of the normal teflon) is really cool. I will use them to mount my engine instead of the self tapping screws into nylon that came with the plane (BH Matrix 60). So no worries!

As for the markets in Taiwan. I will let you know if I can find a 3.5 mm nut. The funny thing here is that so many of the the nuts and bolts here are actually using inches!!! I may end up epoxying it instead!