What makes a shaft whippy?
- Thread starter CeaseLess
- Start date
The wood itself, the diameter, and the taper.
Taper is enough for me. That changes with CF but I have yet to go there.
Incidentally, there's this carbon tube weave that's not actually new but looks promising for pool sticks and maybe cloth as well.
Incidentally, there's this carbon tube weave that's not actually new but looks promising for pool sticks and maybe cloth as well.
Flakeandrun
Well-known member
When I use the term, I refer pretty much only to the flex.
CeaseLess
Active member
Can you elaborate on the wood coming into play, admittedly I'm not too knowledgeable on the subject.
CeaseLess
Active member
Does the flex soely come from the diameter
Some wood does not have as much "spine" as other wood.
There could be a variety of things that contribute to that.
The wood isn't aged enough, it doesn't have enough growth rings, high moisture content, grain runout, etc.
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Flakeandrun
Well-known member
I think the density of the wood and the taper will be the contributing factors. Perhaps you could "ask the cue maker" section
RidgeRaider
Active member
The general term I like to use for this, is "spine". It's a term more commonly used in Archery, where they measure the stiffness of their arrow shafts (both wood and carbon fiber) in a numbered scale of 100-1000 spine. Spine strength is basically the overall rigidity of the given piece (shaft). In theory, longer and thinner objects have less spine, shorter and thicker objects have more spine (assuming working with wood and carbon fiber).
So, the spine of a cue shaft for the most part will come down to a few things. The type of wood used, the diameter of the shaft, and the length of the shaft. Carbon fiber is different, but still mainly comes down to the wall thickness and diameter / length.
Softer wood, longer shaft length, thin diameter (like 12mm) are going to make for a super whippy shaft unless counteracted like a lot of makers nowadays do.
So, the spine of a cue shaft for the most part will come down to a few things. The type of wood used, the diameter of the shaft, and the length of the shaft. Carbon fiber is different, but still mainly comes down to the wall thickness and diameter / length.
Softer wood, longer shaft length, thin diameter (like 12mm) are going to make for a super whippy shaft unless counteracted like a lot of makers nowadays do.
This is pure structural mechanics stuff.
The stiffness of a shaft is proportional to the 4th power of its diameter and inversely proportional the the square of its length.
Given that the length of the shaft is essentially constant::
The stiffness is proportional to 4th power (d^4) its diameter integrated along the length of the shaft. {Timoshenko}
List of second moments of area - Wikipedia
So, the thinner the shaft is, and the longer the taper is, the whippier it is.
Now as to taper, since diameter is increasing as the taper progresses, the tip of the shaft is a lot more whippy than 1/3rd of the way back, the tip is vastly whippier than 2/3rds of the way back. {50 years ago I could "do the math" but that day is gone}
If it goes
“Whipshayaew”
“Whipshayaew”