LD CF?

[Patrick Johnson]

CF is about 3 times as dense as maple, so to make a CF shaft that deflects (squirts) less than a solid maple shaft of the same diameter, it must have less than 1/3 the cross sectional area of the solid maple shaft at the tip. That means for a 12.7mm (1/2") shaft the CF version must be hollowed out until the remaining walls are less than 3/64" thick (see below).

Is that even feasible? Are 3/64" CF walls strong enough for a pool cue's shaft?

pj
chgo

 

[rexus31]

I don't know how thick the walls are of the shaft but the foam core must play a role in the strength, structure and deflection.

 

[garczar]

CF is about 3 times as dense as maple, so to make a CF shaft that deflects (squirts) less than a solid maple shaft of the same diameter, it must have less than 1/3 the cross sectional area of the solid maple shaft at the tip. That means for a 12.75mm (1/2") shaft the CF version must be hollowed out until the remaining walls are less than 3/64" thick (see below).

Is that even feasible? Are 3/64" CF walls strong enough for a pool cue's shaft?

pj
chgo

View attachment 631948

When i tried the Revo 12.9 i was kinda amazed they could get good LD out of 12.9mm shaft.

 

[garczar]

I don't know how thick the walls are of the shaft but the foam core must play a role in the strength, structure and deflection.

The foam is there mostly for vibration/sound tuning. Most of them are hollow for a few inches below the ferrule/tip-plate. The tubes are more that strong enough without it. I imagine the sound w/o any filler would be really annoying.

 

[Patrick Johnson]

I don't know how thick the walls are of the shaft but the foam core must play a role in the strength, structure and deflection.

Yes, but even light foam adds some weight, so it's (very minimally) counterproductive as far as squirt itself is concerned.

pj
chgo

 

[Patrick Johnson]

The foam is there mostly for vibration/sound tuning. Most of them are hollow for a few inches below the ferrule/tip-plate. The tubes are more that strong enough without it. I imagine the sound w/o any filler would be really annoying.

Have you measured the walls on any?

pj
chgo

 

[garczar]

Have you measured the walls on any?

pj
chgo

Haven't felt like cutting one open. I've seen a Prather blank and the walls are really thin up near the tip. I msg'd Carbonoid and they said you could make a hollow shaft but it would be very light and might sound strange. Might be worth trying one just for shits-n-giggles.

 

[Ģüśţāṿ]

Prather mentions the ID and OD of their carbon tubes, wall thickness is right around 0.07" or just shy of 5/64 with a +/- 0.035 tolerance.

 

[Patrick Johnson]

Prather mentions the ID and OD of their carbon tubes, wall thickness is right around 0.07" or just shy of 5/64 with a +/- 0.035 tolerance.

Thanks for the info. If that's the thickness of 1 wall, not two (both sides), then it's about 50% thicker than the maximum I calculated above...?

pj
chgo

 

[hang-the-9]

CF is about 3 times as dense as maple, so to make a CF shaft that deflects (squirts) less than a solid maple shaft of the same diameter, it must have less than 1/3 the cross sectional area of the solid maple shaft at the tip. That means for a 12.7mm (1/2") shaft the CF version must be hollowed out until the remaining walls are less than 3/64" thick (see below).

Is that even feasible? Are 3/64" CF walls strong enough for a pool cue's shaft?

pj
chgo

View attachment 631949

It must be feasible because the thicker Revo plays without breaking and has pretty low deflection.

However there are very very few 12.7 mm LD shafts in wood or CF, most are 12.5 or thinner.

 

[garczar]

It must be feasible because the thicker Revo plays without breaking and has pretty low deflection.

However there are very very few 12.7 mm LD shafts in wood or CF, most are 12.5 or thinner.

More than you might think. Predator,Viking,OB,GO,Pechauer and McD. all offer cf shafts in 12.75 or bigger.

 

[Patrick Johnson]

It must be feasible because the thicker Revo plays without breaking and has pretty low deflection.

However there are very very few 12.7 mm LD shafts in wood or CF, most are 12.5 or thinner.

FYI, here are some smaller shaft sizes and the corresponding thickness of CF walls that would equal the mass of solid maple shafts.

The constant is that, in order to weigh less than a solid maple shaft of the same size, a CF shaft's walls must total less than about 18% of the total diameter (of any size shaft).

pj
chgo

 

[hang-the-9]

More than you might think. Predator,Viking,OB,GO,Pechauer and McD. all offer cf shafts in 12.75 or bigger.

I have seen very few of them in the wild, and most I see people were looking to trade to a smaller diameter. Two in my local room, they had 12.9s, wanted to get something thinner, and several in the facebook groups looking to trade for thinner ones. Of the Predator shafts, I think the 12.4 is just right, I would guess it's a large bulk of sales in that size.

 

[dr_dave]

CF is about 3 times as dense as maple, so to make a CF shaft that deflects (squirts) less than a solid maple shaft of the same diameter, it must have less than 1/3 the cross sectional area of the solid maple shaft at the tip. That means for a 12.7mm (1/2") shaft the CF version must be hollowed out until the remaining walls are less than 3/64" thick (see below).

Is that even feasible? Are 3/64" CF walls strong enough for a pool cue's shaft?

pj
chgo

View attachment 631949

Check out the cross-section photo of the Revo and other info here:

LD shaft endmass resource page​

The carbon fiber shell is very thin (since it is so strong). The mass of the foam is probably insignificant.

For convenience, here's the photo:

 

[Patrick Johnson]

Check out the cross-section photo of the Revo and other info here:

LD shaft endmass resource page​

The carbon fiber shell is very thin (since it is so strong). The mass of the foam is probably insignificant.

For convenience, here's the photo:

Thanks, Dave.

I'm surprised the walls can be so thin - definitely thin enough to be lighter than solid maple, and maybe even lighter than Predator's hollowed out walls. The cylindrical shape must have a lot to do with it.

pj <- as usual, I shoulda started at https://billiards.colostate.edu/
chgo

 

[Patrick Johnson]

I imagine the sound w/o any filler would be really annoying.

Wear ear buds, annoy your opponent and look clueless.

pj
chgo