REPLY TO PIN QUESTION,trueblue,jschelin99-top hat cue, whammo57

[avscue]

the original post asked about about g10 pins

http://forums.azbilliards.com/showthread.php?t=301039

i had posted this - the g10 pin is a premium pin, i personally would leave it alone. i've never seen them coming apart but they do have sharper crowns than the metal. the pin is used for less weight and to protect the butt and shaft if it were to fall over....the pin would break instead of putting stress on the joint and possibly splitting the shaft or screwing up the collar. you just drill out the glass pin parts that are broke and replace. if you lightly buff the pin, you should not have any problems.

got an interesting response - Perhaps I'm totally wrong, but...

Pins are made out of G10 because it's light yet very strong. I highly doubt "ease of replacement" factored into the picture. Yes, G10 pins are far easier to machine out than a metal pin. Then again, when replacing a metal pin it's much easier to heat the pin to break down the glue.

As far as the G10 pin "protecting" the joint during a fall... Huh? Have you ever tried to break a G10 pin? Clamp one in a vise and whack it with a hammer. I guarantee you they're stronger than you're describing. If an "accident" occurs that breaks the G10 pin, I'd be willing to bet there's going to be more repairs needed to the cue than just a new pin.

The typical "problem" with G10 pins is this: G10 pins can only effectively be made into large threaded pins (3/8-10, Radial, etc.) which screw into wooden threads in the shaft. The raw G10 material is quite abrasive and over time it will grind down the inner surface of the wooden threads causing the joint to loosen up. Some remedies are wax or thin CA on the G10 threads.

G10 pins are no more "premium" than stainless, brass, or aluminum.


it inspired this experiment - g10 threaded into scrap shaft. put in vise and with just a light push on the shaft (about 6" from the joint collar) i get this.

now about that guarantee......

 

[bdcues]

Your experiment is faulty.

 

[JoeyInCali]

To create those threads, they are subjected to side to side stress.
If they break that easily, those threads wouldn't get made.

I agree with BD.
G10 rods cost more than alum, SS or Brass.

 

[avscue]

well, buy the pin and try it yourself. its a g10 pin that got stressed.

 

[FLYINGSNAIL]

wrong post sorry... Happy New Year!!!

 

[whammo57]

the original post asked about about g10 pins

http://forums.azbilliards.com/showthread.php?t=301039

i had posted this - the g10 pin is a premium pin, i personally would leave it alone. i've never seen them coming apart but they do have sharper crowns than the metal. the pin is used for less weight and to protect the butt and shaft if it were to fall over....the pin would break instead of putting stress on the joint and possibly splitting the shaft or screwing up the collar. you just drill out the glass pin parts that are broke and replace. if you lightly buff the pin, you should not have any problems.

got an interesting response - Perhaps I'm totally wrong, but...

Pins are made out of G10 because it's light yet very strong. I highly doubt "ease of replacement" factored into the picture. Yes, G10 pins are far easier to machine out than a metal pin. Then again, when replacing a metal pin it's much easier to heat the pin to break down the glue.

As far as the G10 pin "protecting" the joint during a fall... Huh? Have you ever tried to break a G10 pin? Clamp one in a vise and whack it with a hammer. I guarantee you they're stronger than you're describing. If an "accident" occurs that breaks the G10 pin, I'd be willing to bet there's going to be more repairs needed to the cue than just a new pin.

The typical "problem" with G10 pins is this: G10 pins can only effectively be made into large threaded pins (3/8-10, Radial, etc.) which screw into wooden threads in the shaft. The raw G10 material is quite abrasive and over time it will grind down the inner surface of the wooden threads causing the joint to loosen up. Some remedies are wax or thin CA on the G10 threads.

G10 pins are no more "premium" than stainless, brass, or aluminum.


it inspired this experiment - g10 threaded into scrap shaft. put in vise and with just a light push on the shaft (about 6" from the joint collar) i get this.

now about that guarantee......

That sure makes me want to put one in my cue.............LOL

thanks for the experiment

Kim

 

[JoeyInCali]

well, buy the pin and try it yourself. its a g10 pin that got stressed.

There are hundreds , if not thousands, of cues out there with radial joint pins.
If it had breaking problems , makers would quit using them now.

I don't see 5/16 aluminum pins out there either.

Your experiment is faulty as DP said.
You put the pin on a vice, not a cue with two faces mated together.
When the cue is jointed, the weakest point is in the stroking area.

My house cue has a G10 pinned extention

 

[bdcues]

Joey's point about the mating faces is the key failure of the OP's test. In your pics you can see where the vice contacted the shoulder of the pin. In your test I would not expect the pin to do any else but snap off. If you are going to needlessly break good pins and happen to have more of them I can send you my address instead and will put them to good use.
My cue, with a G-10 pin, has fallen a couple to the floor a couple of times. I am not worried about the pin breaking off. If the shaft was not tight... you might get the same results as your vise did. Otherwise I think not. Have you heard or seen a large number of posts on here asking how to remove broken G-10 pins?

 

[avscue]

the test was by no means a "failure". i think its being misunderstood. i was challenged to put a g10 in a vise and whack it with a hammer. so... i did, but didn't even have to use a hammer to snap it. i was certain it would because thats what the Mfg. had claimed. still, to give the challenger the benefit of the doubt, i had personally never broke one or had one break to date, maybe the challenger is correct. well, the pics show the results. this test was not intended to discredit the g10 radial (a pin i like) or to put fear in ones that have or use them. i think it gives merit to the Mfrg.'s claim and possibly protect the cue. i don't think the pin would break on any piloted joint but on flat faced joints or if it wasn't tightened would break and protect the cue from further damage. dropping on the floor may not break it but if the cue were in a case,shaft connected, leaning on a table and it slides off and the shaft strikes a chair....that may be a different outcome. anyway, interesting responses again. whammo57, i wouldn't hesitate to use the g10 radial, it will be fine. now i have to check the ease of getting it out, i suspect no problems.

 

[JoeyInCali]

. now i have to check the ease of getting it out, i suspect no problems.

It is the easiest joint screw to remove.

 

[Chopdoc]

the test was by no means a "failure". i think its being misunderstood. i was challenged to put a g10 in a vise and whack it with a hammer. so... i did, but didn't even have to use a hammer to snap it.

Seems clear to me. It was a challenge. That's all.


.

 

[Chopdoc]

To the OP,

The thing to understand about screws is that they are not designed not intended for anything but axial (tension) forces. The test you performed applied a shear/moment force.

A properly designed screw joint (not just cues, anything) should rely completely on the friction between the two surfaces to react all sliding, bending and twisting loads.

dld

Engineering and design is one thing (really two). Real world is another.

When I was building small blocks over 400 cubic inches in the mid-eighties I was told all sorts of stories by technicians at the machine shop who thought they were engineers. Usually they were wrong. But that's another story.

One of the interesting (but simple) things I learned about fasteners was that the skinnier ones often were better. Let me clarify. On the main cap bolts of a modified small block with splayed outer bolts one would find that thicker bolts sheered off under high loads (read drag racing) right at the top of the threads. Thinner bolts that did not taper down to meet the threads actually tolerated higher forces. Obviously to those who understand such things this is very basic stuff, but really very counter-intuitive to many people.



Engineering vs design vs real world

The design guys always screw up the engineering and the real world guys ultimately screw up the design. In the end the real world always wins.

He was challenged. It would seem to be a silly challenge so of course he tried it. Of course the pin failed miserably in the challenge. It wasn't engineered or designed for the forces encountered anyway, but that wasn't the point now was it? He was challenged to do this.

I am reminded of the collapse of a pedestrian bridge inside a building. The engineers specified certain fasteners at certain intervals. The design guys didn't like it so they changed it. At the grand opening the bridge was overloaded and collapsed. The engineers said they didn't specify it that way and the designers said that so many people should not have been on it. In the end the real world won...and people died.



.

.

 

[Paul Dayton]

he testexamined the screw in a way it was never designed for beingused.

 

[iusedtoberich]

DoubleD, did you go to Drexel University? That collapse was part of my eng ethics class also. The lesson I recall from it is that the design was so different than anything existing at the time, that it was the ethical duty of the engineers to be there on site to supervise the building.

 

[Chopdoc]

Failure of a joint pin is pretty benign, but can serve as a learning point for other, possibly dangerous situations.

dld

Engineering cannot ever fully compensate for human stupidity. People do dumb things all the time...hence we have warning labels on things like plastic bags.

Interestingly, human ingenuity can apparently overcome engineering limitations in ways that sometimes inspire. "This widget was never designed to do that!" It brings to mind things like Apollo 13.

Yes DoubleD, I believe it was the Kansas City Hyatt Regency I mentioned. I find it's a good one to mention because anybody with education in engineering and /or design immediately knows the case.


Fasteners are interesting. I learn a lot from you guys.


.

 

[whammo57]

Engineering and design is one thing (really two). Real world is another.

When I was building small blocks over 400 cubic inches in the mid-eighties I was told all sorts of stories by technicians at the machine shop who thought they were engineers. Usually they were wrong. But that's another story.

One of the interesting (but simple) things I learned about fasteners was that the skinnier ones often were better. Let me clarify. On the main cap bolts of a modified small block with splayed outer bolts one would find that thicker bolts sheered off under high loads (read drag racing) right at the top of the threads. Thinner bolts that did not taper down to meet the threads actually tolerated higher forces. Obviously to those who understand such things this is very basic stuff, but really very counter-intuitive to many people.



Engineering vs design vs real world

The design guys always screw up the engineering and the real world guys ultimately screw up the design. In the end the real world always wins.

He was challenged. It would seem to be a silly challenge so of course he tried it. Of course the pin failed miserably in the challenge. It wasn't engineered or designed for the forces encountered anyway, but that wasn't the point now was it? He was challenged to do this.

I am reminded of the collapse of a pedestrian bridge inside a building. The engineers specified certain fasteners at certain intervals. The design guys didn't like it so they changed it. At the grand opening the bridge was overloaded and collapsed. The engineers said they didn't specify it that way and the designers said that so many people should not have been on it. In the end the real world won...and people died.



.

.

Is that the difference between a cut thread and a rolled thread?

Kim

 

[ratcues]

Weight reduction and ease of removal were not even in my head as to why I switched to G10 pins.

As to this experiment, yes, they can be broken. I broke several with very little torque. But, I will add this; I'd much rather replace the broken G10 pin vs a bent/broken pin out of any type of metal.

 

[jschelin99]

Avscue: Yes, you are correct that I said to put a G10 radial pin in a vise and whack it with a hammer. I didn't mean to be literal and set a challenge for you, but I applaud you following through with the experiment.

To clear up any misunderstandings:
- I'm not a joint pin expert.
- I'm not a G10 expert.
- I'm not the world's best cue maker.
- I can be an incredible smart-aleck, and sometimes my sarcasm is mistaken for grumpiness.

The reason for my original response was that I just didn't agree with some of your statements, and thought I'd put in my 2 cents worth. Hence, the disclaimer "perhaps I'm totally wrong".

As pointed out above, your experiment doesn't apply in the real world. To do so would require breaking, or attempting to break, a cue with a G10 pin. Since no sane person would purposefully break a perfectly good pool cue, I suggested the vise.

If you feel like following through with the "break a cue with a G10 pin" challenge, I'd be interested to see the results. If the cue is tightly screwed together, with the butt and shaft squarely mated, and you break it, I'd be willing to bet more than just the G10 pin will need to be repaired.

 

[Chopdoc]

Is that the difference between a cut thread and a rolled thread?

Kim

I honestly don't remember exactly. It's been almost 30 years.

I do seem to remember that may have something to do with it.





.

 

[EddySJ]

threads...

Is that the difference between a cut thread and a rolled thread?

Kim

A rolled threading process does not remove material to form the threads.
The threads are compressed into the metal stock/rod with machinery.
This type of process strenthens the metal due to hardening from cold work.
Grain flow patterns in the metal are not interupted when rolled.
Higher production rates are possible with rolled threads.
Higher fatigue life and better surface finish are also benefits of rolled threads.

"Strain hardening" or "cold work" should produce some good search results if you were interested in knowing more details.


We also discussed the walkway case in my Engineering Forensics class. I recall the discussion centering on the changes made to the drawings that were not fully reviewed by the design engineer. That change was regarding the fastening system mentioned in detail in the earlier posts. (Our discussion was somewhat topical, but it seems to agree with what was said earlier.)

Is the G-10 material now available to everyone in black and green? At one point, the Cue Components site had a statement that they were the only authorized folks to have the black G-10.