Table Difficulty Factor (TDF) for measuring table "toughness"

Not too many Olhausens. Here are my data:

Brand: Olhausen York

Table Size Factor (TSF): (9 ft) = 1.00
Pocket Size Factor (PSF): (13.1 cm) = 0.88
Pocket Angle Factor (PAF): (13.1 cm – 10.9 cm = 2.2 cm) = 1.04
Pocket Shelf Factor (PSF): (4.3 cm) = 1.00

Total Table Difficulty Factor (TDF): 0.92

I always thought my table played harder than those in most pool halls due to the pocket angle and deep shelf causing many rattles of seemingly well-struck balls. Guess the large pocket size somewhat negates that.
 
Cardigan Kid said:
I have another table for your list, Doc.

Premium Billiards, Syracuse, NY
Table 7 (Gold Crown 3 modified by Mark Gregory w Artemis cushions)
4 1/2" mouth
3 3/4" throat
1 1/16" shelf
Click to expand...
Here's what I've added:

Cardigan Kid -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/16":0.95 -- 0.97 (GC III Table 7 at Premium Billiards, Syracuse, Mark Gregory-modified w/ Artemis cushions)


Cardigan Kid said:
I thought the table played on the more difficult side of average with the "diamondized" pocket sizes, but the calculator kicks out average.
Click to expand...
Remember, 4 1/2" pockets (PSF=1.00) are in the "average" range.

I agree with others that the shelf depth seems a bit small. Did you measure it carefully based on the illustration and instructions in the first post?

Catch you later,
Dave
 
Cardigan Kid said:
Interesting how the shelf trumps pocket size, I always thought it was the other way around. Whenever someone describes how difficult a table is, or the mosconi high run controversy (what size table/pockets compared to today's takes)-the pocket sizes are always discussed. Rarely ever here the shelf size discussed.
Click to expand...
Look at the numbers in the tables that define the factor values in the TDF document. Pocket size does make a big difference. Also, pocket facing angle and shelf depth become more important as the size of the pockets gets smaller. It's all in the numbers.

Catch you later,
Dave
 
beetle said:
Not too many Olhausens. Here are my data:

Brand: Olhausen York

Table Size Factor (TSF): (9 ft) = 1.00
Pocket Size Factor (PSF): (13.1 cm) = 0.88
Pocket Angle Factor (PAF): (13.1 cm – 10.9 cm = 2.2 cm) = 1.04
Pocket Shelf Factor (PSF): (4.3 cm) = 1.00

Total Table Difficulty Factor (TDF): 0.92
Click to expand...
FYI, the PAF should be 1.03, not 1.04.

Here's what I've added:

beetle -- 9':1.00 -- 13.1cm:0.88 -- 2.2cm:1.03 -- 4.3cm:1.00 -- 0.91 (Olhausen York)

beetle said:
I always thought my table played harder than those in most pool halls due to the pocket angle and deep shelf causing many rattles of seemingly well-struck balls. Guess the large pocket size somewhat negates that.
Click to expand...
Exactly. Those pockets are huge. They might rattle balls more easily than a bar box, but they certainly have a large "center" where rattles are not a concern.

Thank you for posting,
Dave
 
Here's the latest:

Measurements and data reported by AZB users for table difficulty factor (TDF), based on the table size factor (TSF), pocket size factor (PSF), pocket angle factor (PAF), and pocket shelf factor (PLF):

name -- table_size:TSF -- pocket_mouth_size:PSF -- mouth-throat_difference:PAF -- shelf_depth:PLF -- TDF (table description)
Vahmurka -- 12':1.25 -- 7.2cm:1.55 -- 125deg:0.97 -- 25mm:0.98 -- 1.84 (12ft Russian pyramid table)
dr_dave -- 10':1.10 -- 4":1.20 -- 3/4":1.02 -- 1 7/8":1.03 -- 1.39 (fictitious tough 10' table example)
Bob Dixon -- 9':1.00 -- 4":1.20 -- 145deg:1.14 -- 1 5/8":1.00 -- 1.37 (Pool Sharks, Las Vegas, money table, Diamond Pro-Am, red logo, Ernesto Dominguez-modified)
dr_dave -- 9':1.00 -- 3 7/8":1.25 -- 5/8":1.00 -- 2 1/8":1.07 -- 1.34 (fictitious example "B")
Bonus Ball -- 9':1.00 -- 3 7/8":1.25 -- 1/8":0.97 -- 3/4":0.98 -- 1.19 (Bonus Ball table)
chevybob20 -- 9':1.00 -- 4 1/8":1.15 -- 7/8":1.05 -- 1":0.98 -- 1.18 (Mark Gregory modified Centennial)
Qaddiction -- 9':1.00 -- 4 1/8":1.15 -- 3/4":1.02 -- 1 3/8":0.99 -- 1.16 (Diamond)
rexus31 -- 9':1.00 -- 4":1.20 -- 3/8":0.98 -- 1":0.98 -- 1.15 (mid to late 50's AMF Commercial Model similar to a Brunswick Anniversary/Sport King)
FatBoy -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 1":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
TATE -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 7/8":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
pocket -- 9':1.00 -- 4 3/16":1.10 -- 7/16":0.99 -- 1 7/8":1.03 -- 1.12 (unknown)
Neil -- 7':0.85 -- 4 1/8":1.15 -- 1 1/4":1.14 -- 1 3/8":0.99 -- 1.10 (modified Valley "bar box")
MahnaMahna -- 10':1.10 -- 5 1/2":0.85 -- 2":1.09 -- 2 1/2": 1.07 -- 1.09 (snooker table poorly converted into a pool table)
Cardigan Kid -- 9':1.00 -- 4 1/4":1.10 -- 0.45":0.99 -- 1 5/16":0.99 -- 1.08 (GC II)
cigardave -- 9':1.00 -- 4 1/2":1.00 -- 1":1.07 -- 1 3/4":1.00 -- 1.07 (typical Pro-Cut Diamond)
Pool Hustler -- 9':1.00 -- 4 1/4":1.10 -- 1/4":0.97 -- 15/16":0.98 -- 1.05 (modified GC, measured by rexus31)
JC -- 9':1.00 -- 4 7/16":1.00 -- 143deg:1.07 -- 1 3/8":0.98 -- 1.05 ("Cobrasized" GC III)
SloMoHolic -- 9':1.00 -- 4 1/2":1.00 -- 7/8":1.04 -- 1 3/8":0.98 -- 1.02 (2005 Diamond Pro with ProCut pockets and Red-label rails)
CoreyClark -- 9':1.00 -- 5":0.91 -- 1":1.07 -- 2 1//8":1.05 -- 1.02 (GC I)
"standard" table -- 9':1.00 -- 4 7/16":1.00 -- 9/16":1.00 -- 1 5/8":1.00 -- 1.00 (average-difficulty table)
dr_dave -- 9':1.00 -- 5": 0.91 -- 1 1/8":1.10 -- 1 3/8":0.99 -- 0.99 (old GC II at MatchUps, Fort Collins)
MVPCues -- 9':1.00 -- 4 1/2":1.00 -- 1/2":0.98 -- 1 5/8":1.00 -- 0.98 (Antique Brunswick Jefferson, circa 1900)
oldschool1478 -- 9':1.00 -- 4 1/2":1.00 -- 0.625":1.00 -- 1.5":0.98 -- 0.98 (updated Red Badge Diamond Pro)
Cardigan Kid -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/16":0.95 -- 0.97 (GC III Table 7 at Premium Billiards, Syracuse, Mark Gregory-modified w/ Artemis cushions)
BryanB -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.97 (1931 Brunswick with double shimmed pockets)
Poolmanis -- 9':1.00 -- 10.9cm:1.05 -- 1cm:0.97 -- 3.1cm:0.95 -- 0.97 (modified SAM)
Vahmurka -- 9':1.0 -- 12.5cm:0.91 -- 20mm:1.04 -- 45mm:1.03 -- 0.97 (Brunswick Metro)
mamics -- 9':1.00 -- 4 11/16":0.95 -- 143deg:1.07 -- 1 3/16":0.95 -- 0.97 (no-name "Chinese Cheapie" with Uylin cushions)
dzcues -- 9':1.00 -- 4 7/8":0.91 -- 11/16":1.02 -- 1 15/16":1.03 -- 0.96 (typical League-Cut Diamond)
dzcues -- 9':1.00 -- 5":0.91 -- 15/16":1.07 -- 1 1/2":0.98 -- 0.95 (Gandy Big G)
Sloppy Pockets -- 8'+:0.95 -- 5":0.91 -- 1 1/8":1.10 -- 1 3/4":1.00 -- 0.95 (A.E. Schmidt)
44Runner -- 8'+/-:0.925 -- 4 3/8":1.05 -- 3/4":1.02 -- 1":0.95 -- 0.94 (8' Diamond Pro-Am - blue label)
beetle -- 9':1.00 -- 13.1cm:0.88 -- 2.2cm:1.03 -- 4.3cm:1.00 -- 0.91 (Olhausen York)
frigopie -- 9':1.00 -- 11.5cm:0.95 -- 138.7deg:0.98 -- 3.5cm:0.98 -- 0.91 (Eurotour Dynamic III)
12squared -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/2":0.98 -- 0.91 (GC home table)
iusedtoberich -- 9':1.00 -- 5 1/8":0.88 -- 1":1.05 -- 1 1/2":0.97 -- 0.90 (GC)
MSchaffer -- 9':1.00 -- 5 1/8":0.88 -- 3/4":1.01 -- 1 3/4":1.00 -- 0.89 (GC II)
mfinkelstein3 -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC III)
StraightPoolIU -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.88 (GC I)
Vahmurka -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC)
Dopc -- 8':0.90 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.87 (8' Connelly Kayenta)
SloMoHolic -- 8':0.90 -- 4 3/4":0.95 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.87 (old 8' Brunswick Medalist league table)
RobMan -- 9':1.0 -- 5": 0.88 -- 3/4":1.01 -- 1.5":0.97 -- 0.86 (GC)
SloMoHolic -- 8'+:0.95 -- 4 7/8":0.91 -- 7/8":1.04 -- 1 1/4":0.95 -- 0.85 (Brunswick Medalist at Stardust Club in Manchaca, TX)
nateobot -- 7':0.85 -- 4 3/8":1.05 -- 1/2":0.95 -- 1 3/4":1.00 -- 0.85 (custom-made)
dr_dave -- 8':0.90 -- 4 3/4":0.95 -- 5/8":1.00 -- 1 3/8":0.98 -- 0.84 (8' Connelly home table)
BRussell -- 8':0.90 -- 5":0.91 -- 13/16":1.04 -- 1 1/2":0.98 -- 0.83 (8' Olhausen)
jtaylor996 -- 7':0.85 -- 5 1/8":0.88 -- 146deg:1.09 -- 1.51":1.00 -- 0.82 (7' Legacy home table)
dr_dave -- 8':0.90 -- 5":0.91 -- 1/2":0.98 -- 1 3/8":0.98 -- 0.79 (fictitious 8' example "A")
Mooneye -- 7':0.85 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.79 (7' Brunswick "Ranchero")
SloMoHolic -- 6':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 5/8":0.95 -- 0.77 (old 6' Valley "bar box")
dzcues -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 1/2":0.95 -- 0.77 (7' Valley "bar box")
dr_dave -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 3/4":0.95 -- 0.77 (7' Valley "bar box" at West End, Fort Collins)
 
Dr. Dave,

Has there been a push to get the TDF statistic into the sport of pool such as the accu stats TPA?

I truly believe, with your and Mr. Jewitt's influence, you could get a dialogue with Pat over at accu stats and the party poker folks behind the mosconi cup to start using the TDF statistic in current and future events.

After a few years it will become commonplace for pool fanatics to debate TDFs and results, like we do with TPAs and results.

Also,

Could a side pocket measurement be added to the official three corner pocket measurements to more accurately gauge a table's difficulty level?
 
Cardigan Kid said:
Dr. Dave,

Has there been a push to get the TDF statistic into the sport of pool such as the accu stats TPA?

I truly believe, with your and Mr. Jewitt's influence, you could get a dialogue with Pat over at accu stats and the party poker folks behind the mosconi cup to start using the TDF statistic in current and future events.

After a few years it will become commonplace for pool fanatics to debate TDFs and results, like we do with TPAs and results.
Click to expand...
Honestly, Bob and I probably don't have any real "influence" with Accustats or Party Poker, but they and anybody else are certainly welcome to use the TDF system. Everything needed is online, and it can be used freely, as is or modified. Maybe it would help if you and others write or call to request this. I agree with you that it would be nice to have a quantitative measure of table difficulty for all events, especially those streamed and televised.

Cardigan Kid said:
Could a side pocket measurement be added to the official three corner pocket measurements to more accurately gauge a table's difficulty level?
Click to expand...
It would be nice to add many other things (side pocket measurements, cloth and cushion condition effects, pocket-wall vertical angle, etc.), but I personally like it the way it is ... as simple as possible while capturing the most important attributes of a table.

Regards,
Dave
 
dr_dave said:
Honestly, Bob and I probably don't have any real "influence" with Accustats or Party Poker, but they and anybody else are certainly welcome to use the TDF system. Everything needed is online, and it can be used freely, as is or modified. Maybe it would help if you and others write or call to request this. I agree with you that it would be nice to have a quantitative measure of table difficulty for all events, especially those streamed and televised.

It would be nice to add many other things (side pocket measurements, cloth and cushion condition effects, pocket-wall vertical angle, etc.), but I personally like it the way it is ... as simple as possible while capturing the most important attributes of a table.

Regards,
Dave
Click to expand...

Yes, sir. You got it. I'll do my part and make an effort to push the TDF more this year. Maybe get upstate Al to utilize it for the streaming table at the next Turning Stone classic. That could be a start.
And yes, simple is always a better option. I can see your point in not weighing in other factors.
 
Cardigan Kid said:
Yes, sir. You got it. I'll do my part and make an effort to push the TDF more this year. Maybe get upstate Al to utilize it for the streaming table at the next Turning Stone classic. That could be a start.
And yes, simple is always a better option. I can see your point in not weighing in other factors.
Click to expand...
Thanks! I'll also continue to help spread the word.

FYI, the best place to direct people for TDF info is here:
billiards.colostate.edu/threads/table.html#table_difficulty_factor
or just tell them to Google "table difficulty factor."

Catch you later,
Dave
 
Last edited:
Here's a new entry I received via PM:

freds said:
Here's the numbers from the Gandy I got installed a couple months ago. (These are new/replacement rails, don't know what kind.)

table_size, TSF: 8+, 0.95
pocket_mouth_size, PSF: 4.9", 0.91
mouth-throat_difference, PAF: 1.1" 1.1
shelf_depth, PLF: 1.8" 1.03

TDF: .98

Gandy Big G, oversized 8
Click to expand...
 
Here's the latest updated list:

Measurements and data reported by AZB users for table difficulty factor (TDF), based on the table size factor (TSF), pocket size factor (PSF), pocket angle factor (PAF), and pocket shelf factor (PLF):

name -- table_size:TSF -- pocket_mouth_size:PSF -- mouth-throat_difference:PAF -- shelf_depth:PLF -- TDF (table description)
Vahmurka -- 12':1.25 -- 7.2cm:1.55 -- 125deg:0.97 -- 25mm:0.98 -- 1.84 (12ft Russian pyramid table)
dr_dave -- 10':1.10 -- 4":1.20 -- 3/4":1.02 -- 1 7/8":1.03 -- 1.39 (fictitious tough 10' table example)
Bob Dixon -- 9':1.00 -- 4":1.20 -- 145deg:1.14 -- 1 5/8":1.00 -- 1.37 (Pool Sharks, Las Vegas, money table, Diamond Pro-Am, red logo, Ernesto Dominguez-modified)
dr_dave -- 9':1.00 -- 3 7/8":1.25 -- 5/8":1.00 -- 2 1/8":1.07 -- 1.34 (fictitious example "B")
Bonus Ball -- 9':1.00 -- 3 7/8":1.25 -- 1/8":0.97 -- 3/4":0.98 -- 1.19 (Bonus Ball table)
chevybob20 -- 9':1.00 -- 4 1/8":1.15 -- 7/8":1.05 -- 1":0.98 -- 1.18 (Mark Gregory modified Centennial)
Qaddiction -- 9':1.00 -- 4 1/8":1.15 -- 3/4":1.02 -- 1 3/8":0.99 -- 1.16 (Diamond)
rexus31 -- 9':1.00 -- 4":1.20 -- 3/8":0.98 -- 1":0.98 -- 1.15 (mid to late 50's AMF Commercial Model similar to a Brunswick Anniversary/Sport King)
FatBoy -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 1":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
TATE -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 7/8":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
pocket -- 9':1.00 -- 4 3/16":1.10 -- 7/16":0.99 -- 1 7/8":1.03 -- 1.12 (unknown)
Neil -- 7':0.85 -- 4 1/8":1.15 -- 1 1/4":1.14 -- 1 3/8":0.99 -- 1.10 (modified Valley "bar box")
MahnaMahna -- 10':1.10 -- 5 1/2":0.85 -- 2":1.09 -- 2 1/2": 1.07 -- 1.09 (snooker table poorly converted into a pool table)
Cardigan Kid -- 9':1.00 -- 4 1/4":1.10 -- 0.45":0.99 -- 1 5/16":0.99 -- 1.08 (GC II)
cigardave -- 9':1.00 -- 4 1/2":1.00 -- 1":1.07 -- 1 3/4":1.00 -- 1.07 (typical Pro-Cut Diamond)
Pool Hustler -- 9':1.00 -- 4 1/4":1.10 -- 1/4":0.97 -- 15/16":0.98 -- 1.05 (modified GC, measured by rexus31)
JC -- 9':1.00 -- 4 7/16":1.00 -- 143deg:1.07 -- 1 3/8":0.98 -- 1.05 ("Cobrasized" GC III)
SloMoHolic -- 9':1.00 -- 4 1/2":1.00 -- 7/8":1.04 -- 1 3/8":0.98 -- 1.02 (2005 Diamond Pro with ProCut pockets and Red-label rails)
CoreyClark -- 9':1.00 -- 5":0.91 -- 1":1.07 -- 2 1//8":1.05 -- 1.02 (GC I)
"standard" table -- 9':1.00 -- 4 7/16":1.00 -- 9/16":1.00 -- 1 5/8":1.00 -- 1.00 (average-difficulty table)
dr_dave -- 9':1.00 -- 5": 0.91 -- 1 1/8":1.10 -- 1 3/8":0.99 -- 0.99 (old GC II at MatchUps, Fort Collins)
MVPCues -- 9':1.00 -- 4 1/2":1.00 -- 1/2":0.98 -- 1 5/8":1.00 -- 0.98 (Antique Brunswick Jefferson, circa 1900)
oldschool1478 -- 9':1.00 -- 4 1/2":1.00 -- 0.625":1.00 -- 1.5":0.98 -- 0.98 (updated Red Badge Diamond Pro)
freds -- 8'+: 0.95 -- 4.9":0.91 -- 1.1":1.1 -- 1.8" 1.03 -- 0.98 (Gandy Big G, oversized 8)
Cardigan Kid -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/16":0.95 -- 0.97 (GC III Table 7 at Premium Billiards, Syracuse, Mark Gregory-modified w/ Artemis cushions)
BryanB -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.97 (1931 Brunswick with double shimmed pockets)
Poolmanis -- 9':1.00 -- 10.9cm:1.05 -- 1cm:0.97 -- 3.1cm:0.95 -- 0.97 (modified SAM)
Vahmurka -- 9':1.0 -- 12.5cm:0.91 -- 20mm:1.04 -- 45mm:1.03 -- 0.97 (Brunswick Metro)
mamics -- 9':1.00 -- 4 11/16":0.95 -- 143deg:1.07 -- 1 3/16":0.95 -- 0.97 (no-name "Chinese Cheapie" with Uylin cushions)
dzcues -- 9':1.00 -- 4 7/8":0.91 -- 11/16":1.02 -- 1 15/16":1.03 -- 0.96 (typical League-Cut Diamond)
dzcues -- 9':1.00 -- 5":0.91 -- 15/16":1.07 -- 1 1/2":0.98 -- 0.95 (Gandy Big G)
Sloppy Pockets -- 8'+:0.95 -- 5":0.91 -- 1 1/8":1.10 -- 1 3/4":1.00 -- 0.95 (A.E. Schmidt)
44Runner -- 8'+/-:0.925 -- 4 3/8":1.05 -- 3/4":1.02 -- 1":0.95 -- 0.94 (8' Diamond Pro-Am - blue label)
beetle -- 9':1.00 -- 13.1cm:0.88 -- 2.2cm:1.03 -- 4.3cm:1.00 -- 0.91 (Olhausen York)
frigopie -- 9':1.00 -- 11.5cm:0.95 -- 138.7deg:0.98 -- 3.5cm:0.98 -- 0.91 (Eurotour Dynamic III)
12squared -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/2":0.98 -- 0.91 (GC home table)
iusedtoberich -- 9':1.00 -- 5 1/8":0.88 -- 1":1.05 -- 1 1/2":0.97 -- 0.90 (GC)
MSchaffer -- 9':1.00 -- 5 1/8":0.88 -- 3/4":1.01 -- 1 3/4":1.00 -- 0.89 (GC II)
mfinkelstein3 -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC III)
StraightPoolIU -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.88 (GC I)
Vahmurka -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC)
Dopc -- 8':0.90 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.87 (8' Connelly Kayenta)
SloMoHolic -- 8':0.90 -- 4 3/4":0.95 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.87 (old 8' Brunswick Medalist league table)
RobMan -- 9':1.0 -- 5": 0.88 -- 3/4":1.01 -- 1.5":0.97 -- 0.86 (GC)
SloMoHolic -- 8'+:0.95 -- 4 7/8":0.91 -- 7/8":1.04 -- 1 1/4":0.95 -- 0.85 (Brunswick Medalist at Stardust Club in Manchaca, TX)
nateobot -- 7':0.85 -- 4 3/8":1.05 -- 1/2":0.95 -- 1 3/4":1.00 -- 0.85 (custom-made)
dr_dave -- 8':0.90 -- 4 3/4":0.95 -- 5/8":1.00 -- 1 3/8":0.98 -- 0.84 (8' Connelly home table)
BRussell -- 8':0.90 -- 5":0.91 -- 13/16":1.04 -- 1 1/2":0.98 -- 0.83 (8' Olhausen)
jtaylor996 -- 7':0.85 -- 5 1/8":0.88 -- 146deg:1.09 -- 1.51":1.00 -- 0.82 (7' Legacy home table)
dr_dave -- 8':0.90 -- 5":0.91 -- 1/2":0.98 -- 1 3/8":0.98 -- 0.79 (fictitious 8' example "A")
Mooneye -- 7':0.85 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.79 (7' Brunswick "Ranchero")
SloMoHolic -- 6':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 5/8":0.95 -- 0.77 (old 6' Valley "bar box")
dzcues -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 1/2":0.95 -- 0.77 (7' Valley "bar box")
dr_dave -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 3/4":0.95 -- 0.77 (7' Valley "bar box" at West End, Fort Collins)

_______________________________________

Based on ideas from previous threads on this topic (tight pockets thread and pocket answers thread), and based discussion in the Billiard University (BU) thread concerning how to account for table difficulty in scoring and rating drills like the BU Exams, I decided to create a system for determining how difficult a table plays (based on table and pocket geometry only). It is described in detail in the Table Difficulty Factor (TDF) document, which is convenient if you want a printed copy.

Here's how it works:

The Table Difficulty Factor (TDF) is a percentage measure of how difficult or easy a particular table plays. It is based on table size and the three corner-pocket measurements illustrated below. If the cushion is not 2” (5.1cm) thick, measure the throat size 2” (5.1 cm) back from the cushion noses. You can lay down Post-It Notes or masking tape to better define the lines and intersection points to help with the mouth and throat measurements. If you have an angle-measurement device, you can measure the facing angle directly instead of measuring the throat size. The pocket shelf depth should be measured from the pocket mouth line to the slate top lip edge (where the pocket opening first starts).

table_pocket_measurements.jpg

Four factors are used to account for table size, pocket size, pocket facing angle, and pocket shelf depth. Each factor is a number less than, equal to, or greater than 1, where 1 indicates average or standard. By multiplying the four factors, you get the TDF which is a good measure of table “toughness.” If TDF=1, the table has an average level of difficulty; if TDF>1, the table plays more difficult than average; and if TDF<1, the table plays easier than average.

The four factors are defined as follows:
table_difficulty_TSF.jpg


table_difficulty_PSF.jpg


table_difficulty_PAF.jpg


table_difficulty_PLF.jpg

The total Table Difficulty Factor (TDF) is then calculated by multiplying the four factors:

TDF = TSF x PSF x PAF x PLF​

The TDF can be used to adjust numbers from any scoring or rating system like the Billiard University Exams, “playing the ghost” drills, the Hopkins Q Skills drill, or the Fargo rating drill. An effective score, taking table difficulty into consideration, can be calculated with:

(effective score) = (raw score) x TDF​


NOTE – The TDF and effective-score numbers should not be interpreted too literally since there are so many other factors that contribute to how difficult a table actually plays (cloth type and condition, ball conditions, pocket facing and shim properties, rail and cushion conditions, table levelness, humidity, etc.). Here’s a rough scale one can use to put the TDF factor in better perspective:

table_difficulty_TDF.jpg


Here's an Excel spreadsheet and a mobile-friendly online tool (created by "Isaac") for automatically calculating the TDF factors to determine the difficulty level of a table.
 
My 9-foot Brunswick Anniversary comes in at 1.07. Everything was average except the pocket angle figure. Thanks for the system. Kind of neat to check
 
PlayTrey said:
My 9-foot Brunswick Anniversary comes in at 1.07. Everything was average except the pocket angle figure. Thanks for the system. Kind of neat to check
Click to expand...
Please post your info and I'll add it to the list.

Thanks,
Dave
 
Here's the latest updated list:

Measurements and data reported by AZB users for table difficulty factor (TDF), based on the table size factor (TSF), pocket size factor (PSF), pocket angle factor (PAF), and pocket shelf factor (PLF):

name -- table_size:TSF -- pocket_mouth_size:PSF -- mouth-throat_difference:PAF -- shelf_depth:PLF -- TDF (table description)
Vahmurka -- 12':1.25 -- 7.2cm:1.55 -- 125deg:0.97 -- 25mm:0.98 -- 1.84 (12ft Russian pyramid table)
dr_dave -- 10':1.10 -- 4":1.20 -- 3/4":1.02 -- 1 7/8":1.03 -- 1.39 (fictitious tough 10' table example)
Bob Dixon -- 9':1.00 -- 4":1.20 -- 145deg:1.14 -- 1 5/8":1.00 -- 1.37 (Pool Sharks, Las Vegas, money table, Diamond Pro-Am, red logo, Ernesto Dominguez-modified)
dr_dave -- 9':1.00 -- 3 7/8":1.25 -- 5/8":1.00 -- 2 1/8":1.07 -- 1.34 (fictitious example "B")
Bonus Ball -- 9':1.00 -- 3 7/8":1.25 -- 1/8":0.97 -- 3/4":0.98 -- 1.19 (Bonus Ball table)
chevybob20 -- 9':1.00 -- 4 1/8":1.15 -- 7/8":1.05 -- 1":0.98 -- 1.18 (Mark Gregory modified Centennial)
Qaddiction -- 9':1.00 -- 4 1/8":1.15 -- 3/4":1.02 -- 1 3/8":0.99 -- 1.16 (Diamond)
rexus31 -- 9':1.00 -- 4":1.20 -- 3/8":0.98 -- 1":0.98 -- 1.15 (mid to late 50's AMF Commercial Model similar to a Brunswick Anniversary/Sport King)
FatBoy -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 1":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
TATE -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 7/8":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
pocket -- 9':1.00 -- 4 3/16":1.10 -- 7/16":0.99 -- 1 7/8":1.03 -- 1.12 (unknown)
Neil -- 7':0.85 -- 4 1/8":1.15 -- 1 1/4":1.14 -- 1 3/8":0.99 -- 1.10 (modified Valley "bar box")
MahnaMahna -- 10':1.10 -- 5 1/2":0.85 -- 2":1.09 -- 2 1/2": 1.07 -- 1.09 (snooker table poorly converted into a pool table)
Cardigan Kid -- 9':1.00 -- 4 1/4":1.10 -- 0.45":0.99 -- 1 5/16":0.99 -- 1.08 (GC II)
cigardave -- 9':1.00 -- 4 1/2":1.00 -- 1":1.07 -- 1 3/4":1.00 -- 1.07 (typical Pro-Cut Diamond)
Side Pocket -- 10':1.10 -- 4 7/8":0.91 -- 1":1.07 -- 1 1/2":0.98 -- 1.05 (10' 1920-1925 Brunswick)
Pool Hustler -- 9':1.00 -- 4 1/4":1.10 -- 1/4":0.97 -- 15/16":0.98 -- 1.05 (modified GC, measured by rexus31)
JC -- 9':1.00 -- 4 7/16":1.00 -- 143deg:1.07 -- 1 3/8":0.98 -- 1.05 ("Cobrasized" GC III)
SloMoHolic -- 9':1.00 -- 4 1/2":1.00 -- 7/8":1.04 -- 1 3/8":0.98 -- 1.02 (2005 Diamond Pro with ProCut pockets and Red-label rails)
CoreyClark -- 9':1.00 -- 5":0.91 -- 1":1.07 -- 2 1//8":1.05 -- 1.02 (GC I)
"standard" table -- 9':1.00 -- 4 7/16":1.00 -- 9/16":1.00 -- 1 5/8":1.00 -- 1.00 (average-difficulty table)
dr_dave -- 9':1.00 -- 5": 0.91 -- 1 1/8":1.10 -- 1 3/8":0.99 -- 0.99 (old GC II at MatchUps, Fort Collins)
MVPCues -- 9':1.00 -- 4 1/2":1.00 -- 1/2":0.98 -- 1 5/8":1.00 -- 0.98 (Antique Brunswick Jefferson, circa 1900)
oldschool1478 -- 9':1.00 -- 4 1/2":1.00 -- 0.625":1.00 -- 1.5":0.98 -- 0.98 (updated Red Badge Diamond Pro)
freds -- 8'+: 0.95 -- 4.9":0.91 -- 1.1":1.1 -- 1.8" 1.03 -- 0.98 (Gandy Big G, oversized 8)
Cardigan Kid -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/16":0.95 -- 0.97 (GC III Table 7 at Premium Billiards, Syracuse, Mark Gregory-modified w/ Artemis cushions)
BryanB -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.97 (1931 Brunswick with double shimmed pockets)
Poolmanis -- 9':1.00 -- 10.9cm:1.05 -- 1cm:0.97 -- 3.1cm:0.95 -- 0.97 (modified SAM)
Vahmurka -- 9':1.0 -- 12.5cm:0.91 -- 20mm:1.04 -- 45mm:1.03 -- 0.97 (Brunswick Metro)
mamics -- 9':1.00 -- 4 11/16":0.95 -- 143deg:1.07 -- 1 3/16":0.95 -- 0.97 (no-name "Chinese Cheapie" with Uylin cushions)
dzcues -- 9':1.00 -- 4 7/8":0.91 -- 11/16":1.02 -- 1 15/16":1.03 -- 0.96 (typical League-Cut Diamond)
dzcues -- 9':1.00 -- 5":0.91 -- 15/16":1.07 -- 1 1/2":0.98 -- 0.95 (Gandy Big G)
Sloppy Pockets -- 8'+:0.95 -- 5":0.91 -- 1 1/8":1.10 -- 1 3/4":1.00 -- 0.95 (A.E. Schmidt)
44Runner -- 8'+/-:0.925 -- 4 3/8":1.05 -- 3/4":1.02 -- 1":0.95 -- 0.94 (8' Diamond Pro-Am - blue label)
beetle -- 9':1.00 -- 13.1cm:0.88 -- 2.2cm:1.03 -- 4.3cm:1.00 -- 0.91 (Olhausen York)
frigopie -- 9':1.00 -- 11.5cm:0.95 -- 138.7deg:0.98 -- 3.5cm:0.98 -- 0.91 (Eurotour Dynamic III)
12squared -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/2":0.98 -- 0.91 (GC home table)
iusedtoberich -- 9':1.00 -- 5 1/8":0.88 -- 1":1.05 -- 1 1/2":0.97 -- 0.90 (GC)
MSchaffer -- 9':1.00 -- 5 1/8":0.88 -- 3/4":1.01 -- 1 3/4":1.00 -- 0.89 (GC II)
mfinkelstein3 -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC III)
StraightPoolIU -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.88 (GC I)
Vahmurka -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC)
Dopc -- 8':0.90 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.87 (8' Connelly Kayenta)
SloMoHolic -- 8':0.90 -- 4 3/4":0.95 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.87 (old 8' Brunswick Medalist league table)
RobMan -- 9':1.0 -- 5": 0.88 -- 3/4":1.01 -- 1.5":0.97 -- 0.86 (GC)
SloMoHolic -- 8'+:0.95 -- 4 7/8":0.91 -- 7/8":1.04 -- 1 1/4":0.95 -- 0.85 (Brunswick Medalist at Stardust Club in Manchaca, TX)
nateobot -- 7':0.85 -- 4 3/8":1.05 -- 1/2":0.95 -- 1 3/4":1.00 -- 0.85 (custom-made)
dr_dave -- 8':0.90 -- 4 3/4":0.95 -- 5/8":1.00 -- 1 3/8":0.98 -- 0.84 (8' Connelly home table)
BRussell -- 8':0.90 -- 5":0.91 -- 13/16":1.04 -- 1 1/2":0.98 -- 0.83 (8' Olhausen)
jtaylor996 -- 7':0.85 -- 5 1/8":0.88 -- 146deg:1.09 -- 1.51":1.00 -- 0.82 (7' Legacy home table)
dr_dave -- 8':0.90 -- 5":0.91 -- 1/2":0.98 -- 1 3/8":0.98 -- 0.79 (fictitious 8' example "A")
Mooneye -- 7':0.85 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.79 (7' Brunswick "Ranchero")
SloMoHolic -- 6':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 5/8":0.95 -- 0.77 (old 6' Valley "bar box")
dzcues -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 1/2":0.95 -- 0.77 (7' Valley "bar box")
dr_dave -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 3/4":0.95 -- 0.77 (7' Valley "bar box" at West End, Fort Collins)
 
The latest list is below.

I just added Marc Vidal's table (TDF=1.18). I played on it quite a bit this past weekend. It was quite humbling being used to my 8' with buckets for pockets.

Measurements and data reported by AZB users for table difficulty factor (TDF), based on the table size factor (TSF), pocket size factor (PSF), pocket angle factor (PAF), and pocket shelf factor (PLF):

name -- table_size:TSF -- pocket_mouth_size:PSF -- mouth-throat_difference:PAF -- shelf_depth:PLF -- TDF (table description)
Vahmurka -- 12':1.25 -- 7.2cm:1.55 -- 125deg:0.97 -- 25mm:0.98 -- 1.84 (12ft Russian pyramid table)
dr_dave -- 10':1.10 -- 4":1.20 -- 3/4":1.02 -- 1 7/8":1.03 -- 1.39 (fictitious tough 10' table example)
Bob Dixon -- 9':1.00 -- 4":1.20 -- 145deg:1.14 -- 1 5/8":1.00 -- 1.37 (Pool Sharks, Las Vegas, money table, Diamond Pro-Am, red logo, Ernesto Dominguez-modified)
dr_dave -- 9':1.00 -- 3 7/8":1.25 -- 5/8":1.00 -- 2 1/8":1.07 -- 1.34 (fictitious example "B")
Bonus Ball -- 9':1.00 -- 3 7/8":1.25 -- 1/8":0.97 -- 3/4":0.98 -- 1.19 (Bonus Ball table)
Marc Vidal -- 9':1.00 -- 4 1/8":1.15 -- 7/16":1.05 -- 1":0.98 -- 1.18 (shimmed Brunswick Tournament Edition)
chevybob20 -- 9':1.00 -- 4 1/8":1.15 -- 7/8":1.05 -- 1":0.98 -- 1.18 (Mark Gregory modified Centennial)
Qaddiction -- 9':1.00 -- 4 1/8":1.15 -- 3/4":1.02 -- 1 3/8":0.99 -- 1.16 (Diamond)
rexus31 -- 9':1.00 -- 4":1.20 -- 3/8":0.98 -- 1":0.98 -- 1.15 (mid to late 50's AMF Commercial Model similar to a Brunswick Anniversary/Sport King)
FatBoy -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 1":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
TATE -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 7/8":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
pocket -- 9':1.00 -- 4 3/16":1.10 -- 7/16":0.99 -- 1 7/8":1.03 -- 1.12 (unknown)
Neil -- 7':0.85 -- 4 1/8":1.15 -- 1 1/4":1.14 -- 1 3/8":0.99 -- 1.10 (modified Valley "bar box")
MahnaMahna -- 10':1.10 -- 5 1/2":0.85 -- 2":1.09 -- 2 1/2": 1.07 -- 1.09 (snooker table poorly converted into a pool table)
Cardigan Kid -- 9':1.00 -- 4 1/4":1.10 -- 0.45":0.99 -- 1 5/16":0.99 -- 1.08 (GC II)
cigardave -- 9':1.00 -- 4 1/2":1.00 -- 1":1.07 -- 1 3/4":1.00 -- 1.07 (typical Pro-Cut Diamond)
Side Pocket -- 10':1.10 -- 4 7/8":0.91 -- 1":1.07 -- 1 1/2":0.98 -- 1.05 (10' 1920-1925 Brunswick)
Pool Hustler -- 9':1.00 -- 4 1/4":1.10 -- 1/4":0.97 -- 15/16":0.98 -- 1.05 (modified GC, measured by rexus31)
JC -- 9':1.00 -- 4 7/16":1.00 -- 143deg:1.07 -- 1 3/8":0.98 -- 1.05 ("Cobrasized" GC III)
SloMoHolic -- 9':1.00 -- 4 1/2":1.00 -- 7/8":1.04 -- 1 3/8":0.98 -- 1.02 (2005 Diamond Pro with ProCut pockets and Red-label rails)
CoreyClark -- 9':1.00 -- 5":0.91 -- 1":1.07 -- 2 1//8":1.05 -- 1.02 (GC I)
"standard" table -- 9':1.00 -- 4 7/16":1.00 -- 9/16":1.00 -- 1 5/8":1.00 -- 1.00 (average-difficulty table)
dr_dave -- 9':1.00 -- 5": 0.91 -- 1 1/8":1.10 -- 1 3/8":0.99 -- 0.99 (old GC II at MatchUps, Fort Collins)
MVPCues -- 9':1.00 -- 4 1/2":1.00 -- 1/2":0.98 -- 1 5/8":1.00 -- 0.98 (Antique Brunswick Jefferson, circa 1900)
oldschool1478 -- 9':1.00 -- 4 1/2":1.00 -- 0.625":1.00 -- 1.5":0.98 -- 0.98 (updated Red Badge Diamond Pro)
freds -- 8'+: 0.95 -- 4.9":0.91 -- 1.1":1.1 -- 1.8" 1.03 -- 0.98 (Gandy Big G, oversized 8)
Cardigan Kid -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/16":0.95 -- 0.97 (GC III Table 7 at Premium Billiards, Syracuse, Mark Gregory-modified w/ Artemis cushions)
BryanB -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.97 (1931 Brunswick with double shimmed pockets)
Poolmanis -- 9':1.00 -- 10.9cm:1.05 -- 1cm:0.97 -- 3.1cm:0.95 -- 0.97 (modified SAM)
Vahmurka -- 9':1.0 -- 12.5cm:0.91 -- 20mm:1.04 -- 45mm:1.03 -- 0.97 (Brunswick Metro)
mamics -- 9':1.00 -- 4 11/16":0.95 -- 143deg:1.07 -- 1 3/16":0.95 -- 0.97 (no-name "Chinese Cheapie" with Uylin cushions)
dzcues -- 9':1.00 -- 4 7/8":0.91 -- 11/16":1.02 -- 1 15/16":1.03 -- 0.96 (typical League-Cut Diamond)
dzcues -- 9':1.00 -- 5":0.91 -- 15/16":1.07 -- 1 1/2":0.98 -- 0.95 (Gandy Big G)
Sloppy Pockets -- 8'+:0.95 -- 5":0.91 -- 1 1/8":1.10 -- 1 3/4":1.00 -- 0.95 (A.E. Schmidt)
44Runner -- 8'+/-:0.925 -- 4 3/8":1.05 -- 3/4":1.02 -- 1":0.95 -- 0.94 (8' Diamond Pro-Am - blue label)
beetle -- 9':1.00 -- 13.1cm:0.88 -- 2.2cm:1.03 -- 4.3cm:1.00 -- 0.91 (Olhausen York)
frigopie -- 9':1.00 -- 11.5cm:0.95 -- 138.7deg:0.98 -- 3.5cm:0.98 -- 0.91 (Eurotour Dynamic III)
12squared -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/2":0.98 -- 0.91 (GC home table)
iusedtoberich -- 9':1.00 -- 5 1/8":0.88 -- 1":1.05 -- 1 1/2":0.97 -- 0.90 (GC)
MSchaffer -- 9':1.00 -- 5 1/8":0.88 -- 3/4":1.01 -- 1 3/4":1.00 -- 0.89 (GC II)
mfinkelstein3 -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC III)
StraightPoolIU -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.88 (GC I)
Vahmurka -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC)
Dopc -- 8':0.90 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.87 (8' Connelly Kayenta)
SloMoHolic -- 8':0.90 -- 4 3/4":0.95 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.87 (old 8' Brunswick Medalist league table)
RobMan -- 9':1.0 -- 5": 0.88 -- 3/4":1.01 -- 1.5":0.97 -- 0.86 (GC)
SloMoHolic -- 8'+:0.95 -- 4 7/8":0.91 -- 7/8":1.04 -- 1 1/4":0.95 -- 0.85 (Brunswick Medalist at Stardust Club in Manchaca, TX)
nateobot -- 7':0.85 -- 4 3/8":1.05 -- 1/2":0.95 -- 1 3/4":1.00 -- 0.85 (custom-made)
dr_dave -- 8':0.90 -- 4 3/4":0.95 -- 5/8":1.00 -- 1 3/8":0.98 -- 0.84 (8' Connelly home table)
BRussell -- 8':0.90 -- 5":0.91 -- 13/16":1.04 -- 1 1/2":0.98 -- 0.83 (8' Olhausen)
jtaylor996 -- 7':0.85 -- 5 1/8":0.88 -- 146deg:1.09 -- 1.51":1.00 -- 0.82 (7' Legacy home table)
dr_dave -- 8':0.90 -- 5":0.91 -- 1/2":0.98 -- 1 3/8":0.98 -- 0.79 (fictitious 8' example "A")
Mooneye -- 7':0.85 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.79 (7' Brunswick "Ranchero")
SloMoHolic -- 6':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 5/8":0.95 -- 0.77 (old 6' Valley "bar box")
dzcues -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 1/2":0.95 -- 0.77 (7' Valley "bar box")
dr_dave -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 3/4":0.95 -- 0.77 (7' Valley "bar box" at West End, Fort Collins)

_______________________________________

Based on ideas from previous threads on this topic (tight pockets thread and pocket answers thread), and based discussion in the Billiard University (BU) thread concerning how to account for table difficulty in scoring and rating drills like the BU Exams, I decided to create a system for determining how difficult a table plays (based on table and pocket geometry only). It is described in detail in the Table Difficulty Factor (TDF) document, which is convenient if you want a printed copy.

Here's how it works:

The Table Difficulty Factor (TDF) is a percentage measure of how difficult or easy a particular table plays. It is based on table size and the three corner-pocket measurements illustrated below. If the cushion is not 2” (5.1cm) thick, measure the throat size 2” (5.1 cm) back from the cushion noses. You can lay down Post-It Notes or masking tape to better define the lines and intersection points to help with the mouth and throat measurements. If you have an angle-measurement device, you can measure the facing angle directly instead of measuring the throat size. The pocket shelf depth should be measured from the pocket mouth line to the slate top lip edge (where the pocket opening first starts).

table_pocket_measurements.jpg

Four factors are used to account for table size, pocket size, pocket facing angle, and pocket shelf depth. Each factor is a number less than, equal to, or greater than 1, where 1 indicates average or standard. By multiplying the four factors, you get the TDF which is a good measure of table “toughness.” If TDF=1, the table has an average level of difficulty; if TDF>1, the table plays more difficult than average; and if TDF<1, the table plays easier than average.

The four factors are defined as follows:
table_difficulty_TSF.jpg


table_difficulty_PSF.jpg


table_difficulty_PAF.jpg


table_difficulty_PLF.jpg

The total Table Difficulty Factor (TDF) is then calculated by multiplying the four factors:

TDF = TSF x PSF x PAF x PLF​

The TDF can be used to adjust numbers from any scoring or rating system like the Billiard University Exams, “playing the ghost” drills, the Hopkins Q Skills drill, or the Fargo rating drill. An effective score, taking table difficulty into consideration, can be calculated with:

(effective score) = (raw score) x TDF​


NOTE – The TDF and effective-score numbers should not be interpreted too literally since there are so many other factors that contribute to how difficult a table actually plays (cloth type and condition, ball conditions, pocket facing and shim properties, rail and cushion conditions, table levelness, humidity, etc.). Here’s a rough scale one can use to put the TDF factor in better perspective:

table_difficulty_TDF.jpg


Here's an Excel spreadsheet and a mobile-friendly online tool (created by "Isaac") for automatically calculating the TDF factors to determine the difficulty level of a table.
 
Dr Dave....without reading through the entire thread, do you, or anyone here, find it common for the side pockets to be quite a bit larger then the corners? Does the tabe difficulty need adjusted to compensate? My corners are 4 3/4, and the sides are over 5. Ill just give you my table info.....

American Heritage "Independence"......8 foot. .9

Pocket mouth... 4 3/4.
Pocket throat.... 4. Pocket angle factor... 1.04
PSF.................... .91

Shelf....... 1 1/2" PLF.... 1


For the side pocket..........

Mouth.... 5 1/4
Throat. .. 4 5/8
Shelf... None. The pocket edge is even with cushion.

I intend to extend the rails to close up the sides when I replace cushions. Wont be soon. Lots of life in these yet.
 
Thank you for posting your table info. This is what I get:

buckshotshoey -- 8':0.90 -- 4 3/4":0.95 -- 3/4":1.02 -- 1 1/2":0.98 -- 0.85 (American Heritage "Independence")

I've added it to the list.

Concerning the side pockets, often they are bigger, but they aren't as important to table difficulty as the corners. Also, I wanted to keep things as simple as possible with as few measurements and calculations as possible, while still capturing the most important aspects of table difficulty.

Thanks again,
Dave

buckshotshoey said:
Dr Dave....without reading through the entire thread, do you, or anyone here, find it common for the side pockets to be quite a bit larger then the corners? Does the tabe difficulty need adjusted to compensate? My corners are 4 3/4, and the sides are over 5. Ill just give you my table info.....

American Heritage "Independence"......8 foot. .9

Pocket mouth... 4 3/4.
Pocket throat.... 4. Pocket angle factor... 1.04
PSF.................... .91

Shelf....... 1 1/2" PLF.... 1


For the side pocket..........

Mouth.... 5 1/4
Throat. .. 4 5/8
Shelf... None. The pocket edge is even with cushion.

I intend to extend the rails to close up the sides when I replace cushions. Wont be soon. Lots of life in these yet.
Click to expand...
 
Dave...
I submitted my info a few years back. I recently had RKC come through and re-do my table...here are the new specs:

9' GCII.
4 7/16" at the corners
3 1/2" at the throat
1 5/8" shelf

If I muddled my way through the math, I think I have a 1.07 TDF now (up from 0.89), but I'll see what your official calculations reveal.
 
MSchaffer said:
Dave...
I submitted my info a few years back. I recently had RKC come through and re-do my table...here are the new specs:

9' GCII.
4 7/16" at the corners
3 1/2" at the throat
1 5/8" shelf

If I muddled my way through the math, I think I have a 1.07 TDF now (up from 0.89), but I'll see what your official calculations reveal.
Click to expand...
Thank you for posting the update. I used the online TDF tool to check your numbers, which are correct.

Here's the latest updated list:

Measurements and data reported by AZB users for table difficulty factor (TDF), based on the table size factor (TSF), pocket size factor (PSF), pocket angle factor (PAF), and pocket shelf factor (PLF):

name -- table_size:TSF -- pocket_mouth_size:PSF -- mouth-throat_difference:PAF -- shelf_depth:PLF -- TDF (table description)
Vahmurka -- 12':1.25 -- 7.2cm:1.55 -- 125deg:0.97 -- 25mm:0.98 -- 1.84 (12ft Russian pyramid table)
dr_dave -- 10':1.10 -- 4":1.20 -- 3/4":1.02 -- 1 7/8":1.03 -- 1.39 (fictitious tough 10' table example)
Bob Dixon -- 9':1.00 -- 4":1.20 -- 145deg:1.14 -- 1 5/8":1.00 -- 1.37 (Pool Sharks, Las Vegas, money table, Diamond Pro-Am, red logo, Ernesto Dominguez-modified)
dr_dave -- 9':1.00 -- 3 7/8":1.25 -- 5/8":1.00 -- 2 1/8":1.07 -- 1.34 (fictitious example "B")
Bonus Ball -- 9':1.00 -- 3 7/8":1.25 -- 1/8":0.97 -- 3/4":0.98 -- 1.19 (Bonus Ball table)
Marc Vidal -- 9':1.00 -- 4 1/8":1.15 -- 7/16":1.05 -- 1":0.98 -- 1.18 (shimmed Brunswick Tournament Edition)
chevybob20 -- 9':1.00 -- 4 1/8":1.15 -- 7/8":1.05 -- 1":0.98 -- 1.18 (Mark Gregory modified Centennial)
Qaddiction -- 9':1.00 -- 4 1/8":1.15 -- 3/4":1.02 -- 1 3/8":0.99 -- 1.16 (Diamond)
rexus31 -- 9':1.00 -- 4":1.20 -- 3/8":0.98 -- 1":0.98 -- 1.15 (mid to late 50's AMF Commercial Model similar to a Brunswick Anniversary/Sport King)
FatBoy -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 1":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
TATE -- 9':1.00 -- 4":1.20 -- 1/4":0.97 -- 7/8":0.98 -- 1.14 (Ernesto-Dominguez-modified GC)
pocket -- 9':1.00 -- 4 3/16":1.10 -- 7/16":0.99 -- 1 7/8":1.03 -- 1.12 (unknown)
Neil -- 7':0.85 -- 4 1/8":1.15 -- 1 1/4":1.14 -- 1 3/8":0.99 -- 1.10 (modified Valley "bar box")
MahnaMahna -- 10':1.10 -- 5 1/2":0.85 -- 2":1.09 -- 2 1/2": 1.07 -- 1.09 (snooker table poorly converted into a pool table)
Cardigan Kid -- 9':1.00 -- 4 1/4":1.10 -- 0.45":0.99 -- 1 5/16":0.99 -- 1.08 (GC II)
MSchaffer -- 9':1.00 -- 4 7/16:1.00 -- 15/16":1.07 -- 1 5/8":1.00 -- 1.07 (GCII, RKC mod)
cigardave -- 9':1.00 -- 4 1/2":1.00 -- 1":1.07 -- 1 3/4":1.00 -- 1.07 (typical Pro-Cut Diamond)
Side Pocket -- 10':1.10 -- 4 7/8":0.91 -- 1":1.07 -- 1 1/2":0.98 -- 1.05 (10' 1920-1925 Brunswick)
Pool Hustler -- 9':1.00 -- 4 1/4":1.10 -- 1/4":0.97 -- 15/16":0.98 -- 1.05 (modified GC, measured by rexus31)
JC -- 9':1.00 -- 4 7/16":1.00 -- 143deg:1.07 -- 1 3/8":0.98 -- 1.05 ("Cobrasized" GC III)
SloMoHolic -- 9':1.00 -- 4 1/2":1.00 -- 7/8":1.04 -- 1 3/8":0.98 -- 1.02 (2005 Diamond Pro with ProCut pockets and Red-label rails)
CoreyClark -- 9':1.00 -- 5":0.91 -- 1":1.07 -- 2 1//8":1.05 -- 1.02 (GC I)
"standard" table -- 9':1.00 -- 4 7/16":1.00 -- 9/16":1.00 -- 1 5/8":1.00 -- 1.00 (average-difficulty table)
dr_dave -- 9':1.00 -- 5": 0.91 -- 1 1/8":1.10 -- 1 3/8":0.99 -- 0.99 (old GC II at MatchUps, Fort Collins)
MVPCues -- 9':1.00 -- 4 1/2":1.00 -- 1/2":0.98 -- 1 5/8":1.00 -- 0.98 (Antique Brunswick Jefferson, circa 1900)
oldschool1478 -- 9':1.00 -- 4 1/2":1.00 -- 0.625":1.00 -- 1.5":0.98 -- 0.98 (updated Red Badge Diamond Pro)
freds -- 8'+: 0.95 -- 4.9":0.91 -- 1.1":1.1 -- 1.8" 1.03 -- 0.98 (Gandy Big G, oversized 8)
Cardigan Kid -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/16":0.95 -- 0.97 (GC III Table 7 at Premium Billiards, Syracuse, Mark Gregory-modified w/ Artemis cushions)
BryanB -- 9':1.00 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.97 (1931 Brunswick with double shimmed pockets)
Poolmanis -- 9':1.00 -- 10.9cm:1.05 -- 1cm:0.97 -- 3.1cm:0.95 -- 0.97 (modified SAM)
Vahmurka -- 9':1.0 -- 12.5cm:0.91 -- 20mm:1.04 -- 45mm:1.03 -- 0.97 (Brunswick Metro)
mamics -- 9':1.00 -- 4 11/16":0.95 -- 143deg:1.07 -- 1 3/16":0.95 -- 0.97 (no-name "Chinese Cheapie" with Uylin cushions)
dzcues -- 9':1.00 -- 4 7/8":0.91 -- 11/16":1.02 -- 1 15/16":1.03 -- 0.96 (typical League-Cut Diamond)
dzcues -- 9':1.00 -- 5":0.91 -- 15/16":1.07 -- 1 1/2":0.98 -- 0.95 (Gandy Big G)
Sloppy Pockets -- 8'+:0.95 -- 5":0.91 -- 1 1/8":1.10 -- 1 3/4":1.00 -- 0.95 (A.E. Schmidt)
44Runner -- 8'+/-:0.925 -- 4 3/8":1.05 -- 3/4":1.02 -- 1":0.95 -- 0.94 (8' Diamond Pro-Am - blue label)
beetle -- 9':1.00 -- 13.1cm:0.88 -- 2.2cm:1.03 -- 4.3cm:1.00 -- 0.91 (Olhausen York)
frigopie -- 9':1.00 -- 11.5cm:0.95 -- 138.7deg:0.98 -- 3.5cm:0.98 -- 0.91 (Eurotour Dynamic III)
12squared -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/2":0.98 -- 0.91 (GC home table)
iusedtoberich -- 9':1.00 -- 5 1/8":0.88 -- 1":1.05 -- 1 1/2":0.97 -- 0.90 (GC)
MSchaffer -- 9':1.00 -- 5 1/8":0.88 -- 3/4":1.01 -- 1 3/4":1.00 -- 0.89 (GC II)
mfinkelstein3 -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC III)
StraightPoolIU -- 9':1.00 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.88 (GC I)
Vahmurka -- 9':1.00 -- 5 1/8":0.88 -- 7/8":1.03 -- 1 1/2": 0.97 -- 0.88 (GC)
Dopc -- 8':0.90 -- 4 1/2":1.00 -- 3/4":1.02 -- 1 1/4":0.95 -- 0.87 (8' Connelly Kayenta)
SloMoHolic -- 8':0.90 -- 4 3/4":0.95 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.87 (old 8' Brunswick Medalist league table)
RobMan -- 9':1.0 -- 5": 0.88 -- 3/4":1.01 -- 1.5":0.97 -- 0.86 (GC)
SloMoHolic -- 8'+:0.95 -- 4 7/8":0.91 -- 7/8":1.04 -- 1 1/4":0.95 -- 0.85 (Brunswick Medalist at Stardust Club in Manchaca, TX)
buckshotshoey -- 8':0.90 -- 4 3/4":0.95 -- 3/4":1.02 -- 1 1/2":0.98 -- 0.85 (American Heritage "Independence")
nateobot -- 7':0.85 -- 4 3/8":1.05 -- 1/2":0.95 -- 1 3/4":1.00 -- 0.85 (custom-made)
dr_dave -- 8':0.90 -- 4 3/4":0.95 -- 5/8":1.00 -- 1 3/8":0.98 -- 0.84 (8' Connelly home table)
BRussell -- 8':0.90 -- 5":0.91 -- 13/16":1.04 -- 1 1/2":0.98 -- 0.83 (8' Olhausen)
jtaylor996 -- 7':0.85 -- 5 1/8":0.88 -- 146deg:1.09 -- 1.51":1.00 -- 0.82 (7' Legacy home table)
dr_dave -- 8':0.90 -- 5":0.91 -- 1/2":0.98 -- 1 3/8":0.98 -- 0.79 (fictitious 8' example "A")
Mooneye -- 7':0.85 -- 4 7/8":0.91 -- 3/4":1.02 -- 1 5/8":1.00 -- 0.79 (7' Brunswick "Ranchero")
SloMoHolic -- 6':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 5/8":0.95 -- 0.77 (old 6' Valley "bar box")
dzcues -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 1/2":0.95 -- 0.77 (7' Valley "bar box")
dr_dave -- 7':0.85 -- 4 1/2":1.00 -- 0":0.95 -- 3/4":0.95 -- 0.77 (7' Valley "bar box" at West End, Fort Collins)
 
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