The next logical drill to reinforce the proper hand action is swinging the bat with both hands. Here is a drill that will help you to get the right feel for the proper path of the bat to the hitting zone. The goal is to achieve a short path "to the ball".

Stand facing a fence, holding your back arm straight out so that the tip of your fingers just touch the fence. Now, with bat in hand and utilizing the proper fundamentals, swing the bat through the hitting zone. Concentrate on taking your hands and the knob of the bat "to the ball" of course, this is not MLB swing. The tip of the bat should not hit the fence. If it does, you will get immediate negative feedback.

Hitting the fence is a result of "casting" or "sweeping" your hands through the hitting zone. Typically, this is a result of allowing your elbows to move away from your torso during the swing.

To practice the proper attacking of the hitting zone, bring the wrist action into the swing. The proper wrist action "snaps" the barrel into the hitting area after the hips have launched.

Your belly button should be facing the imaginary pitcher. Their 'good swing' picture does not show this.

We do this drill to make sure our "hands are inside the baseball" and "swing through".

[After the first swing] Great.

Next we are going to challenge our hitters, we can move even closer to the fence.

[After the 2nd swing] Great job. He demonstrates "hands inside the ball" and can "drive through it".

In both swings, he contorted his body, created a non-MLB downward swing path, and in the 2nd swing he also disconnected his back elbow

Use this drill to make sure you are coming through the zone with your hands on the inside. The quickest and shortest path to the ball. ... This is the start of a compact swing... this will promote the ideal swing.
the shortest path to the ball is aka the non-MLB "hands to the ball".

The goal of the drill is to learn a full speed swing without coming into contact with the fence.

This helps the hitter learn the quickest path to the ball when swinging, which will increase bat speed.

Unfortunately, the quickest path does not equate to increased bat speed.

Swing the bat through the hitting zone, concentrating on taking your hands to the ball... bring the wrist action into the swing. "hands to the ball" is not used by most MLB players.

A coach needs to watch to make sure that the batter doesn't lean away from the fence or tuck his elbows. we agree

... swing without the bat touching the fence. The only way she will be able to do this is if the barrel of the bat is lagging behind her hands until her hands have reached a position out in front of her front foot where she wants to make contact with the ball (I call this late bat lag). A good swing with good hip rotation and the proper bat lag will insure that she will be putting all of the energy generated into the ball.

late 'bat lag' is unfortunately a desired objective in linear teaching. Late bat lag makes it easy to foul off and popup the ball, or hit weak grounders

He taught A-Rod his "net drill," which he describes thusly: "You take a stance parallel to a net only a bat-length away from you. You hold the knob of the bat to your stomach to measure the distance. Then, your coach flips balls to you and you hit them -- without the bat touching the net. That's how you know your swing is more compact. The drill forces you to pull your hands towards your body as you swing -- it gets you in the proper position to turn on those inside pitches.

This is the best swing of this group, but I think he's a long way from that net. Even then, his body is slightly contorted.

Create a short compact swing with this simple drill.

It's short and compact but it doesn't look like any MLB swing. Notice the hand push after the back elbow hits the hip.

test the concept yourself before teaching it to your players. Stand close enough to a fence so that the bat will reach from your belly button to the fence. Without moving away from the fence, self-toss (or have someone feed you) balls and see just how effectively you can hit. --- Good luck.

I have often wondered where the idea for the mechanics used in the fence drill came from. Why would we think that accelerating the heel of the bat (or the hands) while keeping the bat head back during a good portion of the swing would result in greater bat speed and a shorter stroke than actively trying to accelerate the bat head from the start?

Various drills which I don't recommend... Fence drill - bat-length away from fence, take a swing with the goal of not hitting the fence. The goal is actually a good one, but unfortunately most hitters modify their swings in ways that are not good. Here's an example of what can happen at the end of the swing of a fence drill (see right).

I don't find casting so difficult to cure that I would resort to the fence drill.