ball marker

[iusedtoberich]

While that marker will work for some tasks, it's apparently the wrong size for others. It should be exactly one ball long and half a ball wide. That allows you to check for clearance for spotting a ball and such. That would be 28.6mm wide and 57.2mm long. Instead it is "Diameter: Approx. 25.7mm" whatever that means and 80mm long according to the picture.

I had a friend who has a small machine shop make me a ball marker from brass. It is an L with arms half a ball long so you can check for clearance. It also has a companion square that fills the arms. This means you can place the L, remove the ball, place the square to fill the L, mark the outside point on the square -- that is the spot where the ball was resting. Or you can reverse the process to place a ball exactly on a spot: place the square and L so that the point of the square is at the spot, remove the square and place the ball against the L.

Thanks! I like this design a lot! I find when trying to place a doughnut "exactly" where the ball rests in order to recreate a shot, it can take many movements of the doughnut.

The removable square piece can even have a modification to it where one of its corners has a concave radius equal to the doughnut radius.

 

[stevekur1]

I just watched a 1 Pocket Match last night, where a player which i wont mention his name requested the cue ball to be cleaned in the middle of the rack to maybe get a better placement on the CB.

Ken Shullman used the ball marker very acurately, using the ball marker like this is so much better than having to use cubes of chalk besides the ball.

Still havent picked up one for myself yet.

-Steve

 

[Bob Jewett]

...
I had a friend who has a small machine shop make me a ball marker from brass. It is an L with arms half a ball long so you can check for clearance. It also has a companion square that fills the arms. This means you can place the L, remove the ball, place the square to fill the L, mark the outside point on the square -- that is the spot where the ball was resting. Or you can reverse the process to place a ball exactly on a spot: place the square and L so that the point of the square is at the spot, remove the square and place the ball against the L.

Here is a drawing of the marker I had made. The dimensions of the arms are exactly half a ball long (1.125 inches) and .293 ball square cross section which is .33 inches. The .293 is found by the Pythagorean theorem for the square that fits outside the ball (side view) and is 1-sqrt(1/2).

The filler square is about half as thick. Its thickness is not important.

 

[iusedtoberich]

Here is a drawing of the marker I had made. The dimensions of the arms are exactly half a ball long (1.125 inches) and .293 ball square cross section which is .33 inches. The .293 is found by the Pythagorean theorem for the square that fits outside the ball (side view) and is 1-sqrt(1/2).

The filler square is about half as thick. Its thickness is not important.

View attachment 409041

Nice. Did you keep a sharp edge on the edges of the L that touch the ball? A deliberate chamfer could also be used, but then the height and/or length would need to be adjusted.

 

[Bob Jewett]

Nice. Did you keep a sharp edge on the edges of the L that touch the ball? A deliberate chamfer could also be used, but then the height and/or length would need to be adjusted.

I broke the edges very slightly. The marker is made of brass.