[Yoda]

Just wanted to share this drill. Been trying to do some left arm only pitches, but would get inconsistent contact (mostly fat and thin shots). Then started trying left arm pitches with my right index finger (simulating PP#3) also touching the grip. The reason, in TGM, PP#3 is what guides the force. In a left arm only swing, I couldn't control the clubhead. With only the index finger, you can't add right arm force. Hope this helps.

Rchang72,

When doing your Left Arm Only drill, make sure you use a little Pivot motion to accelerate the Arm. In other words, do not rely solely on the Left Arm to Pull itself through the Ball. Except in the shortest Strokes, Swinging is all about transferring the rotating Body's momentum into the 'essentially inert' Left Arm and Club.

You're absolutely correct that the Right Forearm and #3 Pressure Point are the ones responsible for keeping the Club 'on track' through Impact, and their absence forfeits a substantial control. However, using a little Pivot to help you through will go a long way toward eliminating those one-arm fat and thin shots.