Reference Lines: 45 Degree Cuts

Very often, a student will tell me “I didn’t shoot that shot because I thought it would scratch.”  So, I will ask them to set up the shot and try.  Quite frequently, they are surprised at the results (usually that they didn’t scratch).

I try to instill this in everyone: know your cue ball paths!

Admittedly, it’s not easy for some people to predict the path the cue ball is going to take in any given situation.  If this is the case for you, all I can tell you is that you’ll figure it out over time.  After a while, it will become natural.

To speed up the learning curve, I propose that you actually spend some time learning some standard reference lines: setups that have predictable outcomes.  Here is the first one (I’ll post more in subsequent posts):

Before I show you the setup, try to answer this: will the following shot result in a scratch in the corner pocket?


Will this shot result in a scratch?

Will this shot result in a scratch?

Before we answer, let’s experiment!  Set up the following shot.  The 1 ball should be in the exact center of the table.  The 15 ball is exactly one diamond down and to the right.  The cue is touching the 15:

Photo May 30, 9 29 19 AM

Now, remove the 15.  If you were to shoot a stop-shot into the 1, making it in the side pocket, you should know that the cue ball will travel along the tangent line to the end rail, like so:

Photo May 30, 9 30 09 AM

I want you to shoot this shot, but instead of a stop shot, make sure the cue ball has natural forward roll.  You can ensure this by hitting with about one tip of follow.  Make the 1 ball with just enough speed to pocket it.  Observe the cue ball’s direction.  If you did everything correctly, the cue ball should end up hitting the end rail about one diamond away from the tangent line, like so:

Photo May 30, 9 30 37 AM

This is repeatable, and should serve as a reference for future shots where you have about a 45 degree cut angle on the shot.

So, let’s revisit our original shot, shall we?  The 1 ball was about a half-diamond away from the side, and the cue ball had a 45 degree cut.  If our calculations are correct, the cue ball should hit the side rail first, and miss the corner pocket, like so:

Photo May 30, 9 32 10 AM

Pretty cool, huh?  With practice, you’ll come to know these reference lines intuitively, and won’t need to think about it!

I am not the originator of this concept.  I must give a shout out to Ralph Eckert, who has an excellent video on this very subject.  Check it out:

If you would like a neat tool to understand cue ball path, I recommend the Total Shot Trainer developed by Nick Varner.  I have one in my training toolbox, and it is every accurate.  You can order one from the Mueller web site (no, I am not a spokesperson… just a fan):,2561.html

Nick Varner's Total Shot Trainer

Nick Varner’s Total Shot Trainer

Special thanks to DrawShot for iOS for the screenshots.

Posted in Practice, Tip of the Day