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

Isaac said:

Dr. Dave,
I believe I now fixed all the issues with Online TDF Calculator.
I ran it on about half of examples published on this thread and there are just few discrepancies:

1. MahnaMahna -- 10':1.10 -- 5 1/2":0.85 -- 2":1.09 -- 2 1/2": 1.15 -- 1.17 (snooker table poorly converted into a pool table)
My calculator gives PLF = 1.07, which is in line with the document (shelf size > 2 1/4, but PSF <= 0.9)

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This was a typo in the list. My spreadsheet agrees with your tool. I've made the correction. Thank you for pointing out the error.

Isaac said:

2. 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)
My PAF is 0.99 vs 0.98 expected. My program converts inches to millimeters, before running the calculations. Mouth-Throat diff is 3/8", which is 9.525mm. After rounding it becomes 10mm, so I pick up 7th and not 8th column in PAF table. I think these metric threshold values should be updated in the document (9mm to 10mm). Could you please confirm?

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You are correct. The rounded cutoff should be 10mm (not 9mm). I've updated this in the document and in the thread image. Again, thank you for pointing this out. Please set the rounded cutoff to 10mm in your tool.

Isaac said:

3. dr_dave -- 9':1.00 -- 5": 0.91 -- 1 1/8":1.10 -- 1 3/8":0.98 -- 0.98 (old GC II at MatchUps, Fort Collins)
I get PLF = 0.99 vs 0.98 expected. I think my value is correct - 5th column from PLF table and 3rd row since PAF >= 1.1.

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Again, this was a typo in the list. My spreadsheet agrees with your tool. I've made the correction. Thank you again for pointing out the error.

Isaac said:

Please let me know if you see any problems of have some enhancements suggestions.

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Other than the 9mm-to-10mm thing, everything seems solid now. Great work. I will certainly use your tool instead of my spreadsheet (after you make the minor change from 9mm to 10mm).

Thanks again for offering this useful tool to the pool community. FYI, I have a link to it on both the AZB TDF thread and the TDF resource page.

Best regards,
Dave

Here's the latest, after the corrections pointed out by Isaac:


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_sizeSF -- mouth-throat_differenceAF -- shelf_depthLF -- 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)
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)
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)

Poolmanis said:

Dave. I probably put measurements wrong because we use metric system here.

Pocket mouth 10,9 cm
Pocket throat 9,9 cm
Shelf depth 3,1 cm

Dunno if it make any difference but if you were kind and check my calculations with these..

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These are slightly different than the English measurements you provided previously. Here's what I get with your metric measurements:

Poolmanis -- 9':1.00 -- 10.9cm:1.05 -- 1cm:0.97 -- 3.1cm:0.95 -- 0.97 (modified SAM)

I've update the list.

Poolmanis said:

I also noticed pocket liners are not totally straight because rail cloth installation so tight at corners it bend em slightly. Pocket mouth would be little bit tighter if they would be straight.

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Actually, take a look at the detailed instructions and illustration at the top of the TDF System document. For best accuracy, you are supposed to measure the mouth at where the flat-faced points would be (not to the rounded point). If you want to measure things more carefully, please feel free to post updated numbers again.

Catch you later,
Dave

Isaac said:

Done, the rounded cutoff metric value of 3/4" is updated to 10mm now.

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Thanks again for your great work.

Best regards,
Dave

Isaac said:

Thank you Dr. Dave!
Also, I'd like to look into automating BU exams score-sheets if you are OK with that.

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That would be awesome. Please proceed and post them on the AZB BU thread when they are available.

FYI, all of the score sheets and forms are available here: billiarduniversity.org/exams.html.

Thanks again,
Dave

nateobot said:

Not to steer this too far off course, but it would be awesome to be able to login/save your BU stats online and then be able to see trends and track your results. :thumbup:

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We don't offer this online, but a spreadsheet for atuomatic scoring and record keeping is available (created by PJ). We also have historical log forms available for manual record keeping here: BU Exam Resources.

Good idea. Maybe if the BU stuff really takes off one day, we will create an app and online database to do what you suggest, and more.

Regards,
Dave

Isaac said:

Thank you Dr. Dave!
Also, I'd like to look into automating BU exams score-sheets if you are OK with that.

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Isaac,

FYI, if you do this, and if you post scores on videos on the AZB BU thread, I will be more than happy to send you a free BU diploma.

Good luck,
Dave