DeeDeeCues
Well-known member
Glad you found it interesting.
In the cases above, increase the distance between the stress risers. Make the tenon/pin deeper in the handle.
Broken pool cue
- Thread starter Jerry J
- Start date
Glad you found it interesting.
In the cases above, increase the distance between the stress risers. Make the tenon/pin deeper in the handle.
Whenever there is a change in diameter replacing a square cut with a radiused cut helps reduce stress at that point. I don't know how possible that may be in a cue but it is typical with metal.
Does the load get distributed around the radius as opposed to flat on the face?
I think more a case of the square cut itself being the stress riser. If you look at a crankshaft all of the journals have radiuses or "fillets" which requires the bearing to be smaller than it could otherwise be. The fillets serve no useful purpose for the connecting rods/bearings or even for the main journals, but the fillets do increase the strength of the crank in an area where cranks typically suffer stress cracks. Someone with mechanical engineering background/education would understand this a lot better than I do.
DeeDeeCues
Well-known member
That isn't completely correct, but a decent way of envisioning it. Consider the stress flowing like water, the water likes the radius, so do the stresses.
That's just about what I see.
Is it just that the flat face offers a convenient shear line?
I'm not sure the reasons but I do know that I pay a steep price for not furthering my education.
What I've heard is cues are fragile when dropped sort of flat to the ground.
I've witnessed a cue that was dropped from a vertical position to flat on the ground and snapped.
IKN, Just sayin, I've seen cues break for no apparent reason.
Das Cue-Boot
Active member
Along with DeeDeeCues very good description of stress risers, we delve into fracture mechanics as well. The point about rounding the pin is very good. The stress at a point is proportional to 1/(radius squared), so giving it a larger radius at the square end reduces the stress concentration at a point. That is why the auto glass places drill a hole into end of the crack propagating on your windshield to increase the radius and reduce the stress at that point.
Any bending or shock on the cue will give a band of high stress at the end of the bolt, which is why we have two pictures posted with fractures right around the end of the squared off bolt.
Das Cue-Boot
Active member
Yes. That is the area with the highest stress, so a flaw or microfracture can grow from that point. Many of the larger cast components exhibit what we call brittle fracture, which is where the material is not resilient and the crack grows almost instantaneously. Wood will do this under some conditions. One of the best examples (well, worst example if you were on the receiving end) were the World War II Liberty ships that were made from steel that was very brittle in the cold north Atlantic. Many of them when hit by a torpedo had a crack propagate up the side of the hull, broke in two and sank in the matter of a minute or two.
Brutal.
So a full splice is actually more sound than a half splice? This makes me wonder about the butt/shaft joint and how that differs.
Break a half splice over your knee. Then try to break a full splice
tomatoshooter
Well-known member
You can use a finger joint if it is concealed
I just noticed that one of the pieces needs to be rotated 180 degrees for proper assembly.
As far a the stress riser discussion, a simple visualization is perforations in a paper towel or how a rip in fabric propagates. Cutting glass is another example.
BuffaloSlim
Active member
I was just looking at a players break cue as a cheap replacement for mine that got swiped at the hall .. after seeing this thread and hearing how they are handling the warranty I definitely will not be buying a players cue
I have played with several (not mine) that were pretty old and all were fine. This is not a normal thing for that brand. I would still recommend them, considering the price point. it's not like you are paying $400 for a US made cue with a lifetime warranty, it's like a $100-150 cue from China.
We need to have some expectations of what one can get for the price and what service one gets. Like picking MetroPCS vs Verizon, I don't know how many people bitch about customer service when they are paying $30 a month vs $60 a month and seem to expect the same service as if they were 5 star clients in first class. There is a reason some things are cheaper, you take that trade-off for the cost savings.
BuffaloSlim
Active member
I get it and i wouldnt expect much from a 100/150 cue.. I guess what struck me funny about it was that I was looking for a break cue and their warranty department was accusing the op of breaking with the cue and sounded like part of the reason for them denying his claim lol
Well now you know it's a #21 shovel handle.
That, and lower quality wood. the void at the end of the screw hole not getting filled with glue. Maybe the hole is off center. Who knows. But that’s not like any maple I’ve seen in a cue before. Just the worm hole alone should make Players warranty the cue.