Deflection question, explain how a stiffer CF shaft has less deflection.

[Bob Jewett]

Did someone get banned 20 years ago?

No, it was about 20 or 25 years ago that the why of deflection started to be generally understood and the details were worked out, largely online.

Nobody was banned. The discussion was tame compared to some of today's threads, and the discussion was on a forum that didn't have a banning mechanism. It was before AZB existed.

 

[heater451]

No, it was about 20 or 25 years ago that the why of deflection started to be generally understood and the details were worked out, largely online.

Nobody was banned. The discussion was tame compared to some of today's threads, and the discussion was on a forum that didn't have a banning mechanism. It was before AZB existed.

Bob, my post was a joke on the "poolscholar" getting deleted. I know that many posts topics are repeated, and certainly will be as long as there are new people coming into the forums--hell, it seems like about 99% of the threads go OT in like the first page of replies, and many of them devolve into the same arguments found in dedicated threads! [Although, specifically about deflection, I expect the topic to have a longer cycle than your standard, "which ball do I look at last" thread.]

Anyway, I can see it wasn't clearly readable as humor, and also apologize for these (my) posts being OT in this thread--they are off, but not meant to be hijacking.

 

[Bob Jewett]

Bob, my post was a joke on the "poolscholar" getting deleted....

No problem. I hadn't noticed that PS had not only been banned but had been deleted. I don't think I've seen that kind of "unmembering" before.

 

[SSP]

I am sensing a new brand of LD shaft it the making.

The bendier, lighter end mass generation.

The Becue Prime II 12.0 shaft is that shaft, it even gives a little feedback, plays the most like a wood shaft I have ever tried, to me it is the perfect blend of CF transfer of power and feel of a traditional wood shaft.

 

[Cornerman]

Did someone get banned 20 years ago?

You’re joking, right?

If you’re not, yes, even if you go back 20 years and find virtually the same thread with the same arguments, the same physics, and the similar posters who swear that every little nuance hasn’t been dissected such that it must negate all the proper understanding and testing we’ve had on this subject, there are at least two banned members on each thread.

 

[Cornerman]

No, it was about 20 or 25 years ago that the why of deflection started to be generally understood and the details were worked out, largely online.

Nobody was banned. The discussion was tame compared to some of today's threads, and the discussion was on a forum that didn't have a banning mechanism. It was before AZB existed.

I found a 2005 thread right here on AZBilliards.

H

Thread 'Deflection, Endmass and Shaft Design'

Apr 24, 2005

I’m new here so I have not seen a lot of the discussions on deflection and shaft design…so for those of you who have followed this conceptually, please don’t let me confuse this issue with old and fully settled questions. Simply point me to the answer and I’ll get up to speed without troubling anyone. I was obliged recently to answer criticism heaped on one of my friends and customers for posting his new cue in the cue gallery and showing his exuberance. In the process, one fellow posted a link to an article on cue ball squirt that uses some quantified methods of physics and maths to...

• HittMan
• Replies: 182
• Forum: Main Forum

 

[Bob Jewett]

I found a 2005 thread right here on AZBilliards.

And that thread does have a number of now-banned participants.

 

[Paul_#_]

Does anyone have a file of the now-deleted posts? I couldn't find it on the WayBack Machine.

 

[Bob Jewett]

Does anyone have a file of the now-deleted posts? I couldn't find it on the WayBack Machine.

I can see several posts like #44 from a deleted member. Were there others?

 

[iusedtoberich]

Leave the past in the past!

 

[Cornerman]

And that thread does have a number of now-banned participants.

I found a couple of interesting posts (interesting maybe only to me). One from Koop, which may have been the impetus for me to get away from using my name in these forums. The other one, which is completely related to this thread, is where I suggested that if somebody could come up with a stiffer material, but keep the mass of the same, then we could test out whether a stiffness has any effect on squirt. Fast forward six years later or so when I had a phone conversation with Dr. Dave on the potential use of a better carbon fiber for a shaft as opposed to the cheaper “graphite” carbon fiber shaft of the time. This was around 2011. The discussion was specifically about a stiff shaft with similar low squirt properties as the LD shafts made of wood.

 

[Paul_#_]

I can see several posts like #44 from a deleted member. Were there others?

There were many posts by AZ-banned 66136 (aka poolscholar). His twenty-seven posts copied below give you an idea of what triggered his banishment. The thread started on August 8th with Pool Scholar first appearing on August 10th at post #44 and his last post, #129, on August 12th:

Stiffness does matter. The original 11.8 mm Revo was flexible and deflected a lot. The newer version is much stiffer and has close to zero deflection.

My theory is that because as shaft flexes it will push the cue ball offline in the opposite direction before it completely leaves the tip. If you've ever hit with an old graphite shaft you can really feel this flexing and increase in deflection

If you have an original 11.8 mm Revo. Try grabbing it at the joint and tip and flexing it. Very flexy vs 12.9 or newer 11.8 revo

You're wrong. It matters a lot

2 reasons why people don't feel it. One they aren't good enough at pool to notice. Two they didn't use enough sidespin. This goes for testing as well. Really need to get closer to 2 tips of side with a smooth firm stroke to generate max deflection

Find an old and new 11.8 revo and you'll have proof. You're not always correct

That's a theory but you need sophisticated experiments to prove this

Yes if you have two shafts which are similar build but vary in flexibility. Then you can learn something potentially

Hopefully with more than 2 but it's tough. Science is hard

You admit flex affects deflection but nobody understands how much.

Posting old articles doesn't prove anything, nor does making one video or having a phd. We need carbon fiber shafts of various flexibility and a robot. Testing anything with a human shooting is suspect and definitely not science

I posted my experience with 11.8 revos... Relating to this thread. Did you read it?

August 11th:

Yes a robot is required for accurate testing. Dr Dave isn't even close to pro and even a pro isn't consistent

Nobody properly understands how shaft flexibility or lack of it affects deflection.

We're where golf was 20 years ago. If you're going to do human testing at least use more than 1 human

not to mention basic sample size issues... we're not in high school science fair are we

Still waiting Dave

Whatever you guys are smoking I want some

I have personally generated way more deflection with 12.4 Revo than 12.9 which contradicts Dave's video. The reason is because the 12.9 is a stiffer shaft

Until a robot or multiple humans test the same shaft with various shaft flexibilities, we don't understand the dynamics of deflection fully.

My point is we don't know. But y'all think dr Dave is correct with sloppy science

Did you know Einstein didn't believe in black holes

Look at the progress in the world the last 20 years and tell me we know everything about pool shafts and nothing matters

It's because everyone is winging it... exactly why the first version of the 11.8 Revo was high deflection. They didn't understand that the flexibility was a factor. Then sometime a year later they fix the design because obviously the first one was incorrect. Of course predator changed the design without telling anyone because they don't want to look incompetent

t's a combo of end mass and how much the shaft flexes at impact and possibly other factors. We need real studies which control variables properly, which we don't have. It's amateur hour out there

If something flexes it will push the opposite direction. This is very obvious if you've ever hit with an old graphite bar cue

This is incorrect. The following is from Dr Dave and explains a stiffer tip deflects less. Same applies to the shaft

Now, the more the tip compresses and flexes sideways, the longer the tip will tend to stay in contact with the CB. This would certainly result in more squirt (CB deflection) because effective “endmass” is larger with a longer contact time. Also, the more the tip flexes sideways, the more the endmass of the shaft moves sideways, which would also tend to create more squirt. A harder tip compresses and flexes less and results in a shorter tip contact time. Therefore, a harder would be expected to produce less squirt, assuming it is not heavier than the tip to which it is being compared

This is a theory, not reality

Where does sideways force come from which pushes a cue ball offline? Think of a diving board, if it's too rigid...then you don't get the force to jump high

Anyone interested in the truth instead of parroting others, read through my replies and Dr Dave's and you will find it. The truth is we don't know how much flex affects deflection but likely more flex means more deflection. This makes intuitive sense and I also have practical experience supporting this

August 12th

I don't make reality, like I said. Dr Dave needs to do some serious science

Think about a diving board. Why does it need to flex and what happens when it's too stiff

I'm not the PhD in the forum. But I do have my own evidence. Just because I'm not doing science doesn't mean I can't judge the lack of science or understanding. There's obviously room to improve our knowledge of shaft physics but God only knows why everyone has their head in the sand

Do some real science Dave come on lol

There's peer review in science. Try that on any video on YouTube

If anyone does any real testing and science be sure to use close to miscue point to generate maximum deflection. Most players aren't comfortable using maximum side spin. With a high deflecting cue you should be able deflect 4 inches at least

 

[Sheldon]

There was a lot of discussion about it back in the good old days of RSB/ASP. Here's a thread from 1998:

Latest Squirt Equations

groups.google.com

 

[336Robin]

The Becue Prime II 12.0 shaft is that shaft, it even gives a little feedback, plays the most like a wood shaft I have ever tried, to me it is the perfect blend of CF transfer of power and feel of a traditional wood shaft.

I will have to find one and give it a whirl.

 

[dendweller]

Not even close, the majority of CF shafts out there are higher deflection. If you've only tried the becue and predator shafts, then I might believe it though. I've hit with several CF shafts that were higher deflection than LD wood shafts, and even non LD wood shafts for that matter. Most of the asian CF blanks that are out there are impossible to make lower deflection without drastic modification.

I bought a cheap cf shaft and it does seem to deflect as much as a standard wood shaft. The one I have would appear to have a small plug ferrule and is assumably hollow given it's a cf tube. I will say it hits like a piece of rebar, it's really stout. I actually like the hit except for the amount of deflection (I'm used to a level of ld around a 314).

It does seem that what you're saying is true in my case and I'm curious if you ideas on the reason for that. Lower quality cf? Over the top stiffness?
Thanks

 

[garczar]

I bought a cheap cf shaft and it does seem to deflect as much as a standard wood shaft. The one I have would appear to have a small plug ferrule and is assumably hollow given it's a cf tube. I will say it hits like a piece of rebar, it's really stout. I actually like the hit except for the amount of deflection (I'm used to a level of ld around a 314).

It does seem that what you're saying is true in my case and I'm curious if you ideas on the reason for that. Lower quality cf? Over the top stiffness?
Thanks

Asian cf shafts come in both reg and lo-defl. When i bought the Crical i got the 'Pro' model and that shaft was fairly lo-d. If you bought the standard Crical you got a higher def. shaft. It all comes down to end mass. The lower squirt shafts uses various ways to do that: thinner tube walls, different(or no) foam filler, lighter ferrules.

 

[bbb]

Asian cf shafts come in both reg and lo-defl. When i bought the Crical i got the 'Pro' model and that shaft was fairly lo-d. If you bought the standard Crical you got a higher def. shaft. It all comes down to end mass. The lower squirt shafts uses various ways to do that: thinner tube walls, different(or no) foam filler, lighter ferrules.

it takes 7 words not 9 pages to answer the question.......
jmho

 

[dendweller]

Asian cf shafts come in both reg and lo-defl. When i bought the Crical i got the 'Pro' model and that shaft was fairly lo-d. If you bought the standard Crical you got a higher def. shaft. It all comes down to end mass. The lower squirt shafts uses various ways to do that: thinner tube walls, different(or no) foam filler, lighter ferrules.

Yep, that my assumption also from all the tests done etc. Guess I'm just surprised that you can get cf this high without putting a big honkin ferrule on it. I've shot with Revos, they are really low. Assumed any hollow tube would beat solid maple by a large margin but I guess I assumed wrong.

Who knows what they filled it with to get it to 4 ounces.

I think what I learned from this made the 90 bucks a good spend.

 

[Patrick Johnson]

For reference, here's a diagram of two 12mm shafts, CF and solid maple, showing how thick the CF walls need to be in order for the shafts to have equal mass (assumes CF's density is 2.5 times maple's). Presumably, these would produce equal deflection. If the maple shaft was hollow at the tip, the CF walls would need to be thinner.

And here's the same pic reduced to show them at more or less normal size:

pj
chgo

 

[Jaden]

I bought a cheap cf shaft and it does seem to deflect as much as a standard wood shaft. The one I have would appear to have a small plug ferrule and is assumably hollow given it's a cf tube. I will say it hits like a piece of rebar, it's really stout. I actually like the hit except for the amount of deflection (I'm used to a level of ld around a 314).

It does seem that what you're saying is true in my case and I'm curious if you ideas on the reason for that. Lower quality cf? Over the top stiffness?
Thanks

I think it comes down to the amount of end mass. Maybe they use more epoxy resin or a thicker tubing. Maybe more heavy of a ferrule.

Aside from the few manufacturers like Becue, Predator, Cuetec and Mezz that make and design their own, I think that most of the people making and selling CF shafts are getting their blanks from the same Chinese manufacturers.

The first AEM shaft that I protoyped I made with a straight taper cf tube and it was VERY low deflection. When I started using the same blanks that I think most people are using I noticed the higher deflection, in some cases EXTREMELY high deflection with pivot points of as low as 6".