Mitch Alsup on 6/26/2009 12:43:53 PM
From BCA Play Pool "Rules and specifications" section found here:
Professional Pool Table Specs:
- Pocket Openings and Measurements
Only rubber facings of minimum 1/16 [1.5875 mm] to maximum ¼ inch [6.35 mm] thick may be used at pocket jaws. The WPA-preferred maximum thickness for facings is 1/8 inch [3.175 mm]. The facings on both sides of the pockets must be of the same thickness. Facings must be of hard re-enforced rubber glued with strong bond to the cushion and the rail, and adequately fastened to the wood rail liner to prevent shifting. The rubber of the facings should be somewhat harder than that of the cushions.
The pocket openings for pool tables are measured between opposing cushion noses where the direction changes into the pocket (from pointed lip to pointed lip). This is called mouth.
- Corner Pocket Mouth: between 4.5 [11.43 cm] and 4.625 inches [11.75 cm]
- Side Pocket Mouth: between 5 [12.7 cm] and 5.125 inches [13.0175 cm] The mouth of the side pocket is traditionally ½ inch [1.27 cm] wider than the mouth of the corner pocket.
- Vertical Pocket Angle (Back Draft): 12 degrees minimum to 15 degrees maximum.
- Horizontal Pocket Cut Angle: The angle must be the same on both sides of a pocket entrance. The cut angles of the rubber cushion and its wood backing (rail liner) for both sides of the corner pocket entrance must be 142 degrees (+1). The cut angles of the rubber cushion and its wood backing (rail liner) for both sides of the side pocket entrance must be 104 degrees (+1).
- Shelf: The shelf is measured from the center of the imaginary line that goes from one side of the mouth to the other - where the nose of the cushion changes direction - to the vertical cut of the slate pocket cut. Shelf includes bevel.
- Corner Pocket Shelf: between 1 [2.54 cm] and 2 ¼ inches [5.715 cm]
- Side Pocket Shelf: between 0 and .375 inches [.9525 cm]
Non-Professional Pool Table Specifications:
POCKET OPENINGS & MEASUREMENTS (cloth-covered rails):
- Pockets openings are measured from tip to tip of the opposing cushion noses where direction changes into the pocket. This is called the mouth.
- Corner Pocket: Mouth 4 7/8” minimum to 5 1/8” maximum
- Side Pocket: Mouth 5 3/8” minimum to 5 5/8” maximum
- The angle at the corner pocket entrance on each side of the pocket is 142º (± 1º).
- The angle at the side pocket entrance on each side of the pocket is 103º (± 2º).
- Vertical Pocket Angle: 12º minimum to 15º maximum
- Shelf: The shelf is measured from the center of the imaginary line that goes from one side of the mouth to the other where the nose of the cushion changes direction to the center of * the vertical cut of the slate pocket radius.
- Corner Pocket: 1 5/8” minimum to 1 7/8” maximum
- Side Pocket: 0” minimum to 3/8” maximum
- Drop Point Slate Radius: The pocket radius measured from the vertical cut of the slate to the playing surface.
- Drop Point Slate Radius: 1/8” radius minimum to ¼” radius minimum
Also see the diagrams in:
http://www.playbca.com/Downloads/Rulebook/CompleteRulebook/tabid/372/Default.aspxbilliardsforum on 6/27/2009 6:40:12 AM
Mitch, do you know what, if anything, table manufacturers are doing or can do to show buyers what, if any, specifications their tables adhere to? Seems like a lot of pool table buyers would overlook this stuff, as it seems nadeau may have done.
I would think that if you play in a league (bca pool league, for example) you'd want to buy a table that adheres to the BCA spec sheet.Mitch Alsup on 6/27/2009 1:00:54 PM
I do not know what any of the pool table manufactures are doing. I suspect that the tables one sees on TV have been "gone over" by one or more table mechanics prior to use in a pro tourney. This would include causing the above dimensions to both exist on the table, and be as identical as possible from pocket to pocket and from table to table.
To a certain extent (the last 1/8th inch) the tables are adjustable from the screws and bolts and the clearances around same. So one couldpull the rails back and get a loose table, or push them inward to get a tight table. I know that the clearances are there so that the rails can be set true, plumb, and square (I had to fix an end rail on my new table that was a little more than 1 degree out of square).
So, given these clearances, I suspect a table mechanic (so inclined) could set up the table to spec or at least measure to see which parameters are or could be set to spec. Over in a different forum, the table mechanics show various means to adjust a table to put pro pockets on a home table by adding a shim here, new rubber there, and liberal use of machine sanders and other carpentry tools.
A little known issue for those looking for pro-tight pockets is the depth of the shelf--which the owner of the table has essentially no way to adjust. The longer the shelf, the tighter the pocket plays. Also the angles of the throat significantly alter the drop-versus-rattle characteristics of the pocket. The actual width of the entrance and mouth of the pocket play somewhat lesser rolls.
Also note: for those with home tables, be sure to check the torque on the rail bolts about once or twice a month to prevent the rails from going out of square and from giving bad angles on balls bouncing off them. Most tables have these bolts at 10-ish foot-pounds--tight enough to deal with the forces without giving, loose enuogh to avoid warping the slate. So, don't crank them down--and don't let them get loose. After a year or two the bolts, slate, and slate frame will achieve the desired hold torque and cease to need monthly checks.
So, back to the posed queston:
I did not see any particular advertizing that states that this table or that table adhears to one set of table specs or another. I suspect this is a quality of implementation and service issue. There may be several specs in use world wide (I don't really know) and many home tables are probably set up on the loose side for the enjoyment of the owners (even the tourneyment quality tables). But, a good table mechanic can set of the table to what you want (assuming you have any idea of what you want) and can tell you after a few minutes measuring things how long and how much it will take. Anyone having the (rubber in the) rails replaced can basically get all this set up at the same time for next to nothing extra.nadeau on 6/29/2009 9:04:47 AM
@Mitch Alsup and @billiardsforum,
Thanks for the great feedback. Being a beginner I found it very helpful.
Its unfortunate that some manufacturers have difficulty following good practice when cutting the rubber at the rail ends. I measured variations of as much as 8 degrees at the corners on my new rails, pre-installed.
When I spoke to a mechanic he didn't sound too surprised and mentioned that things can be adjusted somewhat.