Pool Table Stimpmeter

Joe Waldron*

Pocket Billiards Review

http://www.sunburstselect.com/PBReview/index.htm

January 09

Table speed is important when a player goes from one table to another. The balls, the rails, the cloth, ambient temperature, humidity, as well as the cleanliness of the balls affect the table’s speed or the way in which the balls roll today. At times one player will say the table plays fast today another player may disagree. Is it the players or the table conditions that lead to these statements? Given all of the factors that affect table speed a method for quickly determining how a table plays today would be useful.

Players who attend some of the pool schools learn to control the speed of the cue ball.

The usual or normal pool stroke moves a cue ball about 19 diamonds or the length of a lag shot with return to the middle of the table. This includes hitting the rails twice. Within this range the player learns to control the cue ball within at least one diamond’s distance (12.5 inches on a nine foot table). With further experience a player develops better cue ball control that may be within an inch or two on length of table shots. One’s ability to maintain a consistent normal stroke is important and will vary from day to day based on one’s practice schedule, physical condition etc. With increasing skill it is important to know the table’s condition. The ability to determine if a table plays faster or slower than one’s home table is useful information. With this information a player could learn to quickly adjust their normal stroke for the current table conditions.

Bob Jewett's discusses determining table speed (http://www.sfbilliards.com/articles/1995-04.pdf). The test can be conducted as follows. On a nine foot table, shoot a ball from the first diamond off the head rail. Hit the foot rail and calculate the length of time it takes for the ball to return to the head rail from the foot rail. The ball must be hit in such a way that it returns to the head rail and does not quite touch it. A return time of seven seconds indicates the table is competition speed. This is a good way to gauge a table and gives a reference for table speed. The player might need several shots to get a return exactly to the head rail and of course there is a problem with calculating the time. Jewett states that a stop watch that measures in tenths of a second is recommended. At times the player may need to check both sides of the long rails as well as across the short side. There is a need for a method that could be used reliably, easily and quickly to make these determinations. At times the player may be interested in only the cloth’s speed at other times the rail plus cloth speed give a better idea about table speed.

A Stimpmeter (http://en.wikipedia.org/wiki/Stimp_meter) is used to determine how fast a golf putting green is playing at any given time. This measurement has several uses in the game of golf. The meter is a simple reliable device that is of use to some players. A variation of the Stimpmeter for use on a pool table is described below.

A pool table Stimpmeter needs to be a device that can be easily made and used by any player. It should be inexpensive and easily standardized. Of course there is no particular requirement for a Pool Table Stimpmeter: It is not currently in widespread use.

To create a Pool Table Stimpmeter use a piece of 2” X 4” X 13.5” pine. The length of the 2 X 4 was squared with a table saw. A line was drawn that formed the hypotenuse of a triangle with one side 12.5” long the other was 3.25” long. After the cut was made the meter was cut to be 12.5” long. A ¾” X 3/16” slot was routed in the top of the meter. The back stop for the pool ball was made from a piece of 1.5” X 2” X ¾” pine. It was sanded and painted with white spray enamel. See Photo One

Photo One. The Pool Table Stimpmeter with reference lines.

To standardize the meter the room temperature was brought to 72 degrees with 61% humidity. This is the average humidity for Youngstown, Ohio. Refer to the charts located at http://www.ncdc.noaa.gov/oa/climate/online/ccd/avgrh.html for other cities. The table and the pool balls were cleaned prior to standardizing. Using Jewett’s method it was determined that the table with new 860 Simonis cloth is slightly faster than “competition speed.”

When placed against a rail the drop point for the meter is one diamond away from the rail. On a 9’ pool table there are seven diamonds to the foot rail from the drop point. To determine the Cloth Speed reference line a ball was held against the stop at various places on the ramp until the place was found where the ball would roll up to but not touch the foot rail. The mark was verified at all three diamonds on the table with three attempts at each diamond. The final position was marked with a line and the numeral “7.” A carpenter’s Speed Square was used to square the meter with the rails as shown in Photo One. It was found that the meter is reliable. In general the balls return to within one ball’s width when several attempts are made at each place on the table. In most instances the balls return to within less than one inch of each other when care is taken to insure the ball stop is exactly placed and square with the table.

The maximum distance across the table is three diamonds. Using the procedure outlined above the “3” line was verified for all diamonds down the length of the table.

Individual Table Speed is here defined as a two diamond return from the rail. For the length of the table this is nine diamonds. Across the table this distance is five diamonds. Using the procedure outlined above the reference lines were found and marked as “9” and “5” respectively.

In other tests it was found that changes in humidity by 20% changed the return distance by about one half diamond. A rail bolt on a Gold Crown III was loosened and the ball return distance was reduced by one half diamond.

When the meter set points were used on a seven foot table with Simonis cloth and conversions were made for the differences in distances between diamonds it was determined that the cloth speed was nearly identical. However the Table speed was about 25% slower. A table without Simonis cloth played about 30% slower.

The meter can be used to determine if a table rolls true when a carpenter’s square is used to insure the meter is square with the rail. The results of rolling balls down the side rails will show if pockets fade, if the table is level, and the effects of loose or overly tight cloth.

Dave Alciatore (http://billiards.colostate.edu/) reviewed a preliminary version of this text. His comments and suggestions are appreciated.