LD and Power
- Thread starter Patrick Johnson
- Start date
Don't think so...
lol - Touché.
Here's a visual of a jump shot to help us get a sense of the forces involved. The cue is hitting the cue ball at maximum tip offset (miscue limit), producing maximum squirt. The blue arrow is the direction the shaft is actually pointed, and the black arrows are the directions of the squirt-modified forces generated by low-squirt and high-squirt shafts (2.5° and 5.0° from straight).
I have a hard time accepting that the 2.5° difference between the low-squirt and high-squirt force directions (the two black lines) makes all the difference we see in jumping ability. And this is the maximum difference we'd see from shaft to shaft and shot to shot. Just sayin'.
pj
chgo
But it does. I've had a fair number of lo-defl. shafts and they all jumped like crap. How do you arrive at those squirt numbers?
Something to keep into account if you haven't already. There is a massive increase in the shaft deflection produced when the CB is being forced into the slate.
I'm also interested in where you got those 2.5° and 5.0° numbers. Not that I have measured values to compare against, but I have experienced a far greater disparity between solid maple and say a Z2
I agree - me too. I just doubt it's the small difference in the amounts of squirt that causes it - I'm thinking it must be something else that comes with the squirt difference... like less force.
Given pivot lengths for LD and HD shafts (I assumed 13" and 6 1/2") and the amount of tip offset (I assumed maximum: 9/16"), it's basic geometry to figure those maximum squirt angles.
pj
chgo
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If that matters I think it would be because of shaft stiffness, not squirt (largely unrelated) - so it wouldn't explain why LD shafts jump badly.
pj
chgo
So you are under the impression that shaft stiffness and CB squirt are unrelated...? If that's the case, then I suggest you dig into how LD shafts perform as compared to solid maple. Attempting to discuss this further is pointless until you have this understanding.
You'll have to take that up with Dr. Dave - on his Shaft Endmass and Stiffness Effects resource page he says "it is endmass (not shaft stiffness) that is almost entirely responsible for squirt."
pj
chgo
Play almost every day now, and I'm actually banking balls now at 72 better than I did in my prime years, it's real. Fach Garcia made it for me.
From the same page:
Lateral shaft stiffness can also have a direct effect on squirt since when a stiffer shaft is flexed (as the CB pushes the tip sideways), the shaft reacts with more sideways force, which can create more squirt.
The size of that effect on squirt is minimal - that's why Dave concludes squirt is "almost entirely" caused by endmass. Shaft stifness may play a significant part in jumping, but it doesn't play a significant part in squirt, so it doesn't indicate that squirt itself plays an important part in jumping.
Since you've already started, I recommend reading more of Dave's analysis. You might even run across some comments by me in there.
pj
chgo
Oh... You're still caught up in my use of the term squirt. I already stated that it may not be the most accurate use of the word, and born from my childhood antics.
Move passed that... The rest of my opinion still holds fast
All i ever used was 13mm, ivory ferruled steel-joint cues yrs ago. They were stiff with really big end-mass. Jumping with them was a no-brainer. The hard tips i used didn't hurt either. Could also draw whitey 8ft at any time. Possible my stroke was just awesome.
I think to really test the low deflection vs regular shaft jumping ability, you would need to test two shafts that had the same taper, shaft material, tip diameter, ferrule material, and tip. The only difference between the two needs to be that the end mass is reduced on one of them. The next two jump and break shafts I build I’ll do this. I’ll make them the same except I will do my low deflection steps on one of them and do the other one regularly. I do this already but make my dedicated break shafts low deflection and usually around 13 mm. I make my jump shafts standard and 13.5mm. I’ll make them both 13.5mm and see if I can tell the difference in the way they jump.
I jump fine with pretty much any wallabushka.All i ever used was 13mm, ivory ferruled steel-joint cues yrs ago. They were stiff with really big end-mass. Jumping with them was a no-brainer. The hard tips i used didn't hurt either. Could also draw whitey 8ft at any time. Possible my stroke was just awesome.
pj
chgo
One for the math guy or guys or girl or girls or those of the sixty-some-odd varieties now: With the restriction of motion hitting a ball with a jump cue, how long does tip contact last?
Hu
Hu
I don't know the answer; just want to clarify your question... does "restriction of motion" refer to the cue ball being "stopped" by being driven down into the table surface?
pj
chgo
PJ,
I am talking about all differences between a typical shot and a jump shot. Why isn't really the issue, what I am curious about is duration of time that the tip is in contact with the cue ball. Are we talking 15-20% different or more like 300%?
I am not really going anywhere with this, no hidden motive, just curious. Of course if there is an answer out there it may show up in a discussion somewhere down the road. Just idle mind and idle hands this morning!
Hu