Renfro, that's good info. Thanks for posting that. Do those break cues you're referring to have synthetic tips? What info have you accumulated regarding damage to cue balls from synthetic tips, particularly the measle ball?
Fran for a tip to be in the 90s in energy transfer it is going to likely be some type of phenolic or synthetic... Notice I say some type... no one to my knowledge is using the same phenolic on the break tip as the actual cue ball it is all slightly softer....
The hardest impact you are going to have will be the ball on ball collision of the break.... That collision is going to be as close to 100% energy transfer as we will see in reality...... So for breaking we are hitting the cueball at 26mph with a lets say a 19oz cue.... The impact of the cueball on the head ball is going to be at 24mph against half of the weight of a 9ball rack which would be 1.65 pounds or roughly 26oz(this is being very conservative)... For 10ball and 8ball that number of course is going to go up based on the ball count and the geometry of the rack.....
As far as damage occurring with the different cue balls due to the use of the phenolic/synthetic tips.....
I think there are a few variables at work. Hardness and contact patch size... Some phenolics and the white diamond tips are harder than say the BK2 composite... They also have no resilience so you might as well be striking the cueball with a hammer.
In most instances I still have not seen much in the way of damage on true Aramith cue balls. I have a measles ball, a red circle, and a blue circle and I break with them all...
I looked last night and I have 1 stress crack in the Measles ball. I actually have had that particular crack in the ball for awhile now and it was caused by a white diamond tip on a 11.8mm shaft. That particular tip in that size with a dime radius had a small contact patch on the cueball. The concentrated hit caused damage. The crack is a less than a quarter circle and when it happened it was right outside of the contact patch that could be seen from the chalk residue....
The mezz deep impact is 13mm and the BK2 is 12.75mm and so far I have not seen damage occur using either of them.
I will say this... This is the 3rd measles ball I have had... The first 2 came from a reputable source but they were larger and heavier than the one I have now that I picked up at the Open a few years ago they were also a little different in color...
The first Measles ball I purchased was very very prone to fractures... I was and I am convinced that the lure of easy money has many sources selling the counterfeit as the Aramith measles ball...
I can also tell you that last year I came home with 5 tv sets from the Open.... Couldn't pass them up at 100 a pop.... They were selling both unopened and used sets from the tourney tables... I came home with 4 new sets and a used set.... Todd let me look thru the used sets to pick out the one I wanted and I saw nothing in the way of stress damage on any of the cue balls...
I know many of the pros use the BK2 and Mezz... I tried out the new deep impact pro that Mezz had just sent to Hunter Lombardo... We were waylaying the ball... Granted I max at about 29mph and that is 4-6mph slower than a few of the guys can break, but I didn't notice a single stress crack...
I think the BCAPL overreacted in banning ALL phenolic tips for breaking... I think the issue is likely confined to break cues that have been customized or cues converted to break cues where the shaft/tip is of small diameter and the tip has been chosen just because it's hardest material they can find.
I wish the BCAPL would change the ruling to legalize the factory mezz and predator break cues and then have a size minimum and rockwell hardness rating maximum to address other manufacturers and customized break cues...