optimum joint?

[Canadian cue]

pin types

This topic keeps coming up and although you can not say that one is better than another there is definite differences with pros and cons to all types. Why not start a discussion determining what those pros and cons are that way the customer can make an educated decision. There are only so many variables in the equation and each style of pin has different strengths and weaknesses. Lastly how they are executed is probably the most important factor of them all. For example if we looked at the 5/16 18, the beneficial qualities are it is readily available, a standard in which any cuemaker should have the tools to work on. In combination with a piloted joint and brass insert it is quite robust and will withstand years of use. The cons might be it is not very unique, quite common with the cheap cues as per what has already been mentioned. This combo usually does not have a very tight fit between pin and insert so not allot of surface contact. If we compare this pin to say the 3/8 ten flat rooted pin the pros would be, one it pilots and fastens the cue together in one action, there is no need for a pilot. There is plenty of surface area to transfer feel. The cons would be it is used mostly in combination with wood threads, which is probably not as robust. I also think because the pin is bigger there is less wall thickness to the female side of the joint so it probably won't withstand as much abuse.
If you compare all the pins there are differences of weight, as well as how fast it is to put together. A 5/16 14 is quicker than a 5/16 18 to put together, that may not be important to some but still a difference. There is also the issue of material, different materials have pros and cons too. Brass will bend easier than steel, it will also tarnish.
Anyway my point is you can analyze all the pins and make an educated decision as to which to use. Now how to execute each style is a whole other subject.

 

[Canadian cue]

Looks like you just started the list...

...unfortunately, your pros and cons are still mostly subjective. For instance, you list a loose fit while screwing together as a con. I would argue that tight, friction filled fits are worse.

Of course, my argument would be based in science and engineering, every other argument I've read is based on pixie dust and feathered unicorns flying out of someone's posterior (or a poor understanding of friction, screw threads, alignment features, etc.).

dld

In the engineering world a screw threads only job is to fasten two objects together with strength being the biggest factor. If alignment is important than that job is usually given to another feature, a boss or dowel pin for example. Lastly how a screw thread transmits vibrations is not ordinarily a criteria. Cues bring a unique set of criteria to the question of how to engineer the connection of shaft and cue butt.

 

[cueman]

A cue pin is worthless if it does not sell. So when something starts to not be popular in the market, you can do like I have for years and stick with it or find something that sells. Fortunately I did not have to sell thousands of cues to make a living. Even Meucci has started offering a 3/8-10 pin and I doubt it is because his robot says it plays better. It is market demands. I still feel the small pin is better, yet the main two 5/16 threads have run their coarse of popularity. I had some flat minor diameter 5/16-14 pins made, but did not care for them as they were not visually appealing. The 5/16-10 looks really cool.

 

[Canadian cue]

Hmmm, not true. In the engineering world, I have seen many screw threads that do not fasten two objects together. Sometimes they do exactly the opposite and push two objects apart.

I also know of a lot of aerospace assembly parts that use screw threads to insert alignment pins. Many times these alignment pins are actually part of the screw. The are never part of the screw thread.

Making bastard threads serves nobody. I'm all for adding better alignment features, but, dammit, stop making flat bottomed, dual lead, high friction threads. This is BAD PRACTICE. There is so much technology available now that there is no excuse for making different pins. The only pins I consider valid are: 5/16-18 (hey, you can buy this off the shelf! How neat!), 5/16-14 (this has been around for long enough that it is also an off-the-shelf item, albeit from specialty suppliers) and 3/8-10 (this thread is still a 60deg. vee thread and it allows for the insert required in finer threads to be left out).
I
Any screwing with those threads, like round bottoms (and calling it 'radial'...guess what? All threads are radial, by definition...a thread is simply an inclined plane wrapped around a radius), flat bottoms, unnecessary tight tolerances, etc. is inane and done only by people who don't understand what the hell they are doing.

Want a lighter screw? I can supply you with fifty materials lighter than steel that will do the job. Heavier? At least ten materials.

You can argue this, but the fact remains that you are arguing an indefensible position. I'll let you in on a little secret: All of these new threads were imagineered as gimmicks for marketing purposes only. The pool world is stupid enough to drink that Kool-aid and buy into it, which pushes cuemakers to follow suit and create other new threads.

Ever wonder why Szam never used other threads? Do you think he was stupid? Maybe Franklin and Runde were idiots, also? Hell, Schuler was nearly a genius and one only needs to look at his joint design to figure it out--his piloted joint is simple, elegant, works and is easy to make.

Look, I'm spewing pearls here. If someone wants to actually test joints in a scientific way to figure out what does and doesn't effect important elements in the way a cue performs, I'll help...I have access to probably a million dollars of equipment that can collect potential data. Screw threads aren't the answer to fixing anything--they already do the one job they are supposed to: To hold two pieces of an assembly together (oh, shoot, you told me that isn't what they are supposed to do--my bad).

dld

I will agree that creating odd pitch threads serves no real good purpose and really only makes your product proprietary. As to the thread forms you mentioned Franklin, did he not use the nonstandard 3/8x11 Flat bottom? There is a reason why this thread form has become popular, that intimate fit does lend itself to certain type of feel. You can argue this from a engineering standpoint but I have have experimented for myself and did notice a differance and so did many others. The billiard industry is not the only one with proprietary thread forms. I have encountered a few in the scientific apparatus industry. For example Microscope objectives have a unique standard. As to your point about threads being tested for vibration, I believe it is for a different reason than in cues. They want to be sure the threads do not come apart due to vibration. My point was that in a cue having the pin transmit or conduct the harmonics of the hit is not a usual job asked of a screw thread so why shouldn't the pin also be unique in its design. In my opinion the 3/8 x10 flat bottom does a great job. It holds the two parts of the cue together, it is self aligning no need for a pilot. Lastly it does a great job of producing a great feeling hit. I do realize that my last statement is very subjective but only because it would be a hard thing to test or measure.

 

[Canadian cue]

So, your big argument is one of the most notoriously low quality cue companies out there?

What does SW offer? Barry Szam? Black?

When I see cues that actually command top dollar, they rarely have mezz wavy pins or modified flat-bottomed threads...they have one of the standard three. The coarse of popularity (dang, that was a good pun you used there...coarse instead of course) is a marketing gimmick sold by desperate people to an idiotic populous.

G'day.

dld

What does south west offer? Kinda looks like a modified flat-bottmed thread.... I could be mistaken though.

 

[ratcues]

If someone wants to actually test joints in a scientific way to figure out what does and doesn't effect important elements in the way a cue performs, I'll help...I have access to probably a million dollars of equipment that can collect potential data. Screw threads aren't the answer to fixing anything--they already do the one job they are supposed to: To hold two pieces of an assembly together (oh, shoot, you told me that isn't what they are supposed to do--my bad).

dld

I would love to see this data but I think it would be very difficult to test because of the use of a imperfect biological material, ie wood. Could the testing be done by embedding the pin/insert into a different, more perfect material? Any ideas?

 

[cueman]

So, your big argument is one of the most notoriously low quality cue companies out there?

What does SW offer? Barry Szam? Black?
G'day.

dld

To answer your questions:

My argument has nothing to do with Bob. My point was his robot testing said over and over the small pin was better, yet he is selling the large pin now. I have not asked him why. But I am sure it is because it has become popular.

South West: 3/8-11 flat minor diameter pin with flat face joint. This was a odd ball when it came out. And over 25 years later people still swear to this day that it plays better than a standard 3/8-10. Only time will tell what people say about the 5/16-10 pin in 25 years.

Barry and Black: 5/16-14 pin with piloted joint. Mostly catering to the old school stainless joint people.

 

[ratcues]

I don't really understand how people don't get this: When you use the entire length of a screws minor diameter to create a locating surface, you are introducing a lot of friction and a lot of wear surface. When a locating feature starts to wear, it stops being a locating feature.

dld

I've seen more than my fair shaft of 3/8-10 V threads tear out and have to be replaced. Wood cut in a sharp V, such as the inner threads of a 3/8-10 shaft are susceptible to tearing due to over-tightening and deterioration.

Very few Radial threads tear out, unless they were not properly turned in the first place. The pin is not abrasive. I think the act of screwing the cue together over and over burnishes the inner threads resulting in a nice smooth threading process. Waxing also helps condition the wood.

I'm not arguing against your theories, just that wood is a different animal than metal to metal in the "real world."

 

[ratcues]

I'm guessing that the 3/8-10 failure is down in the sub-1% category.

This may be true but when looking at the number of failures I have seen, a standard 3/8-10 comprise 95% of the failures that I have repaired. Now, do I think there is a design flaw? No. I do think there is a material flaw. Wood cut in a V like the inner threads are not very durable. If you made a phenolic insert, the configuration may last forever. That is one reason I went to the flat minor 3/8-10. I do not want an insert.

I don't think one configuration is better or worse when talking about the overall playability of a cue. I just think it makes a difference, however small. Maybe not in thread count or pitch but in mass and material, as I have stated in past threads.

When you take that small difference and add it to small difference of the forearm wood, ferrule material, handle wood, A joint config, weight bolt system(if any), and even the bumper, tip, etc... You create a unique hit/play quality.

 

[RBC]

My only issue with the Radial pin is the thread pitch.

It's just too coarse of a thread to tighten well. If things aren't perfect, they will loosen because they don't get enough compression of the joint faces. I believe the high thread lead is the primary contributor to this.

This is an interesting thread. Double D I understand quite a bit of your reasoning. It's very sound and logical. If you're ever at one of the larger tournament events that we setup our booth at, I'd love to sit down and talk about this stuff.

 

[Mikey Town]

So, your big argument is one of the most notoriously low quality cue companies out there?

What does SW offer? Barry Szam? Black?

When I see cues that actually command top dollar, they rarely have mezz wavy pins or modified flat-bottomed threads...they have one of the standard three. The coarse of popularity (dang, that was a good pun you used there...coarse instead of course) is a marketing gimmick sold by desperate people to an idiotic populous.

G'day.

dld

I think that this quote could be applied to almost any business, in any arena (well... minus the "coarse" pun).

However, I think that the "desperate people," in most cases, are not desperate... just people wanting to gain market share. Every company tries to distinguish themselves as "different," or "special" in order to earn the business of their prospective clients. I don't think there is anything wrong with that.

As for the "idiotic populous," I think it's more of an "ignorant populous." Don't get me wrong... there are a ton of idiots out there... so many that the public may, in fact, be idiotic. However, using this thread's topic as an example, if cueman told me about his new pin, and the properties that he felt it could improve, I would probably demo a cue or two so I could form an opinion about it. If I really liked his cue, I might even buy one. Would I be buying it for the pin? Probably not, but the pin would have been a reason for me to try it out in the first place... and the marketing would have worked. Does that make me an idiot? No... just ignorant. I don't have the engineering knowledge that you do, because it isn't what I do for a living. Plus, I don't build the cues... I use them. If you were asking me simple questions about mortgage trading on the secondary market, I would not assume that you were an idiot. It's not what you do for a living... it's what I do... so you will be more ignorant to the details than I. That doesn't make you an idiot, though.

That said... I would like to thank you for the information you have provided in this thread. I have learned quite a bit about this subject from your posts and feel that I am far less ignorant than I was before reading them.

 

[scdiveteam]

Mikey,

Thanks for a well thought out post...sometimes mine aren't and I get a bit abrasive.

I am usually pretty tolerant of people's ignorance. I don't think ignorance is bad, in fact (as you mentioned) it is inevitable.

So, I'd like to humbly say that I am sorry to anyone who has been insulted by me in this thread. I will try to do better in the future to present my knowledge and understanding in a more professional way. If I had talked to my customers I would be severely reprimanded.

Take care.

Dave

Dave,

I especially like your fairy dust unicorn metaphor comments in general. I call it urban legend and all industries are replete with things that keep being repeated as gospel. Not that all the things are wrong but are just one approach. To each their own I say,

Engineering is why western civilization prospers to the level of sofisticstion that we enjoy today. So in the end math and practical engineering should rule the day. But as Chris said, proprietary things have a marketable value. One of my pet peeves are pins without a 60 degree center for obvious reasons yet there are a ton of them out there and people like the old school look.

That's why will all make our cues the way we feel is best as well it should be.

Concerning the radial pin, personally I don't like the way they look but that is only an opinion. Objectively they are very good concerning fit IMO if you use a unilock with their tap and specs for hole sizing. I think any problems occur with these pins are when someone buys a pin from another source and uses the unilock tools or vice a versa. Many years ago John Wright showed me a radial pin that Bill Stroud had sent him. He asked John how he thought people would like this new look. At the time JW Cues were the hottest thing in the Chicago Pool hallsand Bill's cues had a simple ACME thread I believe with a rounded nose. John told me he thought Bill was making a bad move and he thought it would effect sales. At that time John was selling these cues in a big way. Well we all know that Bill was right and created something that was a milestone event in the cue world. That's what visionaries do. The radial pin is so popular today because great engineering and proprietary market appeal meet in a big time fashion. How cool it was for Mr. Stroud and hats off to him for sure.

Myself I use a 3/8 14 modified into a Garolite LE insert in my shaft.

I use a drill tap that I had ground undersize to establish hole and the initial threading after pecking. Using a specific chucking reamer to a slightly undersize minor final dimension, then go in with my bottoming tap. It took me buying a few reamers in.0005 increments to find the goldilocks fit where by my threads are firm all the way down to facing but when facing occurs it is home tight whereby you can't force it to rotate and distort the fibers of the insert threads to induce stress in them.

Using the standard size hole for the tap is too loose for my liking so I found my own method to create the interference fit that I like.

JMO,

Rick