Mechanic Q: Why does front end shake intermittently at high speeds??

The front end of my vehicle (and steering wheel) shake intermittently at 70mph+. I've had my tires balanced 3 times in 2 months. Tires are good, brakes are new, alignment is good. Any help/advice you could offer would be greatly appreciated.

Mechanic Q: Why does my steering column shake intermittently??

My steering column shakes intermittently at 70+ mph. I've had my tires balanced 3 times in 2 months. My tire tread is good, new brakes, alignment is good, rims are not warped. The shaking doesn't always happen. Any help or advice you could offer would be greatly appreciated.