Ignition Help

I have an 89 Bronco with the 351W. Within the last 4 months I have gone through 3 Ignition switches. The last went bad after only two starts. Switches work in all positions, except for the final position that cranks the engine. i simply get nothing when i engage the switch all of the way. The truck can be started by crossing the solenoid. Am I just getting faulty switches from the auto parts store, or is this another problem? I took apart a switch and it seems to be only a mechanical part , so I don't believe it could be fried. Does this sound right? I would appreciate any help.

An interesting problem...
So you are able to start the engine a few times, then the switch seems to go badd andd you can't
't start the engine.. you replace the switch adn the same rutine takes place...
So its not the switch, unless there is something in the collare that is broken...
the switch is only a mechanical divise... no voltage passes through it so that can not be the problem.
Are you buying the switch from the same manufacturere??
is so, see if theres another brand.
sorry I'm not very helpfull... electrical are always the hardest to find ...
Best