violent shake in front end when speeds reach 60-61 mph. Tires balanced and rechecked. Front left wheel bearings replaced. Mechanic says parts around wheels are tight. Newer CV joints. Tires good, no bad rims.
The first thing I would try would be to rotate the front wheels to the back. Test drive it and see if the shake moves toward the back. This would indicate an issue with the wheel or tire. Most likely a busted belt in the tire or tires.
Another option that comes to mind would be brake related. If you have a sticking caliper it may go unnoticed until it has been driven for a while and had a chance to heat up. This would intensify a warped rotor.