Joint Pin Experiment

[DeeDeeCues]

As most are probably aware, I hate bastard threads. I don't care so much about different pitches, but prefer standard 60deg thread forms. I'm okay with DZ's modified pin, but I really don't think it offers anything that a standard thread does.

I have wrestled with posting this, but here goes.

I have created a new pin system that fills a few of my desires...and one bonus that I, personally, will never use as a player.

1. The pin has an alignment feature that is separate from the threads.
2. The alignment feature is long enough to act as a proper alignment feature (i.e. greater than one diameter.
3. The threads are industry standard. I am using M6x1.0 because I like metric.
4. The threads are small because, all other things being equal, the smaller diameter thread will create more clamping power than larger diameter threads (basic equation, Force= (coefficient of friction x screw major diameter)/(Torque).
5. The pin should easily be able to be made with different materials to change weight. I'm currently playing with one that is CF and stainless.

I've been playing and breaking with this cue for about a month with no signs of problems. Cue is very solid. The alignment length is ~3x diameter. The thread engagement on both ends is 12mm into stainless inserts. The threads themselves can see no bending load. The alignment barrel makes the threads very difficult to cross-thread...I've tried.

Now the 'bonus' (?). Because the actual connecting pin is designed to not be glued into either portion of the cue, a longer pin can be inserted and a mid-cue extension of any length can be used. Want a 1/2" extension? All you need is a 1/2" long, faced cylinder of whatever material you want with a 8mm bore and a longer joining pin.

Anyhow, there it is, photos below.

 

[r chow]

Interesting. What threads are on the outside of the inserts?

 

[DeeDeeCues]

Interesting. What threads are on the outside of the inserts?

Prototype is unthreaded. My calculations show that decent epoxy is sufficient for the shear load and the lengths should minimize any problems. The shaft insert is 1.75", the butt insert is over 3" to ensure separation of stress risers.

 

[Dave38]

what is the weight of the inserts combined?

 

[DeeDeeCues]

what is the weight of the inserts combined?

The connecting screw is 0.45oz.. The inserts are a total of 0.53oz., with the butt insert being slightly heavier.

Total joint weight as prototyped is effectively 1oz..

 

[DeeDeeCues]

Interesting. What threads are on the outside of the inserts?

what is the weight of the inserts combined?

I appreciate the questions. Critiques are welcome, also.

 

[JoeyInCali]

" As most are probably aware, I hate bastard threads. I don't care so much about different pitches, but prefer standard 60deg thread forms. I'm okay with DZ's modified pin, but I really don't think it offers anything that a standard thread does. "

I disagree . 3/8 10 and 3/8 11 flat bottom threads make for longer lasting wood threads than the regular V's.
It also has much better contact/engagement ratio.
Shaft also spins better on the lathe .
3/8 10 V has too many varieties .
3/8 10 flat bottom is almost all universally with .307-.308 minor now .
BCM used to make them with smaller minor but he stopped .

3/8 10 witn .308 minor is probably the most popular joint screw now . The bastard is now an industry standard .
SW 3/8 11 with 5/16 minor is also now very common . One man makes the joint screws for almost all makers now plus the Chinese have knocked off the 3/8 10 FB with .308 minor . From what I've been told, they've gotten better at it . But, I still buy from the originator .

Your screw configuration is interesting but I don't know if it solves a problem .
If I were to come up with a new joint screw, I'd probably go with 3/8 16 flat bottom .
16TPI makes it easier to live thread and the exposed screw can be shortened to maybe 1" instead of 1.200"-1.275" .

Any joint screw that is longer than 1.3" might have problems fitting cue cases when joint protector is used . That's why a few makers have made their joint screws less than 1 1/4 long .

As far as extension goes , it's becoming so popular that my foreign dealer has pretty much requested it as standard . I now have flat bottom and have extension bumper installed for carbon fiber extension . It changes the bottom configuration a little that I can no longer stamp the inside counter bored face .

 

[Bishop]

First off I think it’s pretty badass to experiment and test new things.

Sometimes I wonder if we’re presenting solutions to things that aren’t a problem.

I’m nowhere near the level of most of you so that’s really just something I ask myself more than anything.

 

[DeeDeeCues]

" As most are probably aware, I hate bastard threads. I don't care so much about different pitches, but prefer standard 60deg thread forms. I'm okay with DZ's modified pin, but I really don't think it offers anything that a standard thread does. "

I disagree . 3/8 10 and 3/8 11 flat bottom threads make for longer lasting wood threads than the regular V's.
It also has much better contact/engagement ratio.
Shaft also spins better on the lathe .
3/8 10 V has too many varieties .
3/8 10 flat bottom is almost all universally with .307-.308 minor now .
BCM used to make them with smaller minor but he stopped .

3/8 10 witn .308 minor is probably the most popular joint screw now . The bastard is now an industry standard .
SW 3/8 11 with 5/16 minor is also now very common . One man makes the joint screws for almost all makers now plus the Chinese have knocked off the 3/8 10 FB with .308 minor . From what I've been told, they've gotten better at it . But, I still buy from the originator .

Your screw configuration is interesting but I don't know if it solves a problem .
If I were to come up with a new joint screw, I'd probably go with 3/8 16 flat bottom .
16TPI makes it easier to live thread and the exposed screw can be shortened to maybe 1" instead of 1.200"-1.275" .

Any joint screw that is longer than 1.3" might have problems fitting cue cases when joint protector is used . That's why a few makers have made their joint screws less than 1 1/4 long .

As far as extension goes , it's becoming so popular that my foreign dealer has pretty much requested it as standard . I now have flat bottom and have extension bumper installed for carbon fiber extension . It changes the bottom configuration a little that I can no longer stamp the inside counter bored face .

Thanks for the well-thought response. We all know that any of the usual suspect threads hold a cue together. I love the piloted barrel on the 3/8-10 modified and in case I wasn't clear, I do use that pin a lot.

Just to be clear, the insert in the shaft is glued in and 1.75". The pin only extends from the butt 1.25in.

Once the inserts are in the butt and shaft, it is the nicest connection I have ever used on my lathe. I use ER32 collets and having the long, unthreaded barrel is great in those.

Since the pin is made to be removable, I could easily change the CF barrel to brass and gain an ounce easily at the joint with no need to ever put the cue in the lathe, anyone who can run a 3mm hex key can change it out at will.

As I mentioned, I like the long barrel for the alignment functionality, and it allows me to use a very small thread that is standard and for which taps are available at any decent hardware store.

Because the barrels are epoxied in, there is actually no need for the maker to even have the taps. The only way anything is going to be harmed is if garbage gets in the insert and someone forcibly screws the cue together. I'm not positive the average person would be able to damage the threads with just their hand strength on the butt and shaft. I could be wrong. I've attempted to be pretty ham-fisted with this and haven't been able to cause problems.

The biggest fear I have right now is actually that it tightens together so well that I can make the joint faces creak. I'm more concerned about splitting a joint collar.

Maybe it never amounts to anything, but if anyone is interested in trying it, I will work with them to send a prototype for minimal expense (covering materials and postage), or send them my design and parts sources. I'm not out to patent this and spend my days in aruba living off that sweeeeet joint cash. I'm more interested in attempting to sway people's perception of joint screws, hopefully eventually denting the wide-held belief that a joint that is hard to screw together is somehow a good thing.


Again, I appreciate the measured response. Have fun and thanks for reading.

 

[DeeDeeCues]

First off I think it’s pretty badass to experiment and test new things.

Sometimes I wonder if we’re presenting solutions to things that aren’t a problem.

I’m nowhere near the level of most of you so that’s really just something I ask myself more than anything.

Thanks! That is mainly the goal, I'm not a believer that the joint pin is a make-or-break deal on a cue, but I hate seeing things like Mezz and their wavy joint that requires a $300 tap.

 

[kgoods]

Interesting! Wethered had a similar idea back in the early 2000s. He did quite a few conversions and even replaced some joints in quality ques around that time. His claims were a more solid joint and quieted the hit. I can't get my head around that last claim, have you noticed a noticeable reduction in the noise of the hit? The biggest issue with his joint was it was too long to fit in most standard cases.

Anyway, this thread might be of interest to you..... https://forums.azbilliards.com/threads/weird-joint.512726/
Someone posted a Joss that had been converted and I posted a couple pics of one I had in the shop at the time.

3/8-10 FB for me.

 

[Mensabum]

Interesting! Wethered had a similar idea back in the early 2000s. He did quite a few conversions and even replaced some joints in quality ques around that time. His claims were a more solid joint and quieted the hit. I can't get my head around that last claim, have you noticed a noticeable reduction in the noise of the hit? The biggest issue with his joint was it was too long to fit in most standard cases.

Anyway, this thread might be of interest to you..... https://forums.azbilliards.com/threads/weird-joint.512726/
Someone posted a Joss that had been converted and I posted a couple pics of one I had in the shop at the time.

3/8-10 FB for me.

Never seen an alignment pin. I hope this takes off for you. If players can feel the difference, you might be on to something. I wonder why other makers haven't incorporated an alignment section of the pin b4 now??

 

[DeeDeeCues]

Interesting! Wethered had a similar idea back in the early 2000s. He did quite a few conversions and even replaced some joints in quality ques around that time. His claims were a more solid joint and quieted the hit. I can't get my head around that last claim, have you noticed a noticeable reduction in the noise of the hit? The biggest issue with his joint was it was too long to fit in most standard cases.

Anyway, this thread might be of interest to you..... https://forums.azbilliards.com/threads/weird-joint.512726/
Someone posted a Joss that had been converted and I posted a couple pics of one I had in the shop at the time.

3/8-10 FB for me.

Great feedback. I don't recall ever seeing that pin...could easily be that I saw it in the distant past and it stuck in my subconscious.

I'm with you, I see no reason that it should be quieter in normal use and have noticed no difference. I would not make a similar claim without empirical evidence and testing. Honestly, I would never test it because developing a valid test would be a nightmare. It would require that that multiple cues were built with the same woods, using the same construction methods, same ferrules, same diameters, etc. just to minimize the variables. On top of that, the amount of calibration and testing of the test equipment would be pretty intensive, along with building valid test equipment that can be shown to be extremely repeatable. I just don't see a benefit. I can say that it seems to sound like a cuestick when hitting balls, and I haven't noticed any weird sounds.

The pin you show seems a bit on the ridiculous side in terms of length, maybe the inventor had an idea about something I haven't considered.

My design worked under the restriction that I didn't want an extremely long portion of the pin extending from the butt--Joey mentioned this and his points were what I considered. I didn't want something that would cause problems in normal cases. This led me to wanting to reduce the diameter of the pin from the nominal 3/8 that is so common now to 8mm. This allowed me to have a long-enough shoulder before the threads engage (aiming for twice the diameter of the shoulder before thread engagement), and to have enough thread engagement (in most metal threads, seven threads of engagement maximizes the strength of the thread, as a general rule). I have more than the two diameters of shoulder engagement and more than seven threads engagement just for a bit of over designing.

Thanks for the contribution!

 

[DeeDeeCues]

Never seen an alignment pin. I hope this takes off for you. If players can feel the difference, you might be on to something. I wonder why other makers haven't incorporated an alignment section of the pin b4 now??

Thanks for the participation. I believe that most players cannot attribute any differences they feel to any one variable in the cue construction. I'm not aware of any valid tests to prove this one way or another. In order to test this, I really think the exact same cue would have to be used for all the tests, changing out the pin between tests, or multiple cues would have to be made from the same wood (cut from the same log, at the same time, etc.). I do know there was a decent blind test conducted that showed people identifying different joint types at about the accuracy as guessing.

Alignment sections aren't exactly new--the Uni-loc does it, the 5/16 piloted joints do, the joint @kgoods showed did it about exactly the same way I am working on, it seems to have been DZ's goal with the 3/8-10 modified. Before seeing the joint posted above, the only joint I have seen that had the alignment feature engage before the threads is the Uni-Loc, and that goes back to the need for a special tap and unnecessary expense.