[mrlmd1]

I don't understand, if the knob turns "forward" to tighten, ie, clockwise, and to reset the odometer also turns clockwise. how is that left hand ( or reverse) threads? Clockwise is the normal direction for almost all screws and nuts and turning the knob clockwise to reset the numbers also tightens the knob on the threaded rod it's attached to. There's no gigantic amount of torque on this thing, so why can't you just glue something onto the threaded rod and if you have to open the speedo case again, just pull it right off if you have to? A ballpoint pen refill, either plastic or metal may be about the right size, just cut it to length, maybe cover the end with a glob of glue or something to get a better grip on it so you can turn it easier.