Carom Cues - Double Joint Shaft

[kilby]

I think that with two sets of threads the problem is to get the force evenly shared between the two. I think that's very hard to produce in practice. The set that's more securely anchored is going to end up with most of the load and the other set will just be along for the ride.

Bob is, of course, exactly correct. IMO, some cuemakers build a unique joint for their cues to encourage future shaft support be directed to them. Not an unreasonable marketing practice, but, beyond being "unique," such joints do not materially add to the performance of the cue.

 

[Texas Carom Club]

Any mechanical engineers/machinists here?

yeah i saw the id of the collar threaded but the od of the wood pilot un threaded
made me chuckle

 

[tomatoshooter]

It says triple threaded, and it looks like there should be threads on the exposed wood of the shaft, but I don't see any. I doubt that the wood/metal contact would do much good anyway.

For the two sets of threads on the pin, I imagine it would not be hard to get the spacing correct, but I think it's pointless. I've heard that for a standard screw connection, three threads basically do all the work. The force is not distributed along the full length of the screw because the metal stretches enough where the the threads are working that the far threads are slack. Or so the theory goes. Any mechanical engineers/machinists here?

Everything I've read supports your statement. I think a general guideline is thread engagement equal to the diameter but of course only a couple are really doing the heavy lifting. I doubt many things are manufactured to tolerances stringent enough to realize the (hypothetical) benefits of this arrangement.

 

[tomatoshooter]

Bob is, of course, exactly correct. IMO, some cuemakers build a unique joint for their cues to encourage future shaft support be directed to them. Not an unreasonable marketing practice, but, beyond being "unique," such joints do not materially add to the performance of the cue.

I think it's like the tourbillion in a watch. The idea was to rotate the pendulum slowly so that the effect of motion from the wearer's walking around would cancel out. Turns out it doesn't make a difference but it's a symbol of the watchmaker's ability.

yeah i saw the id of the collar threaded but the od of the wood pilot un threaded
made me chuckle

I wasn't sure if the threads in the wood were washed out from the light.

 

[Texas Carom Club]

I'm not sure either, it is bright and I thought the same

 

[Black-Balled]

Seriously?

We're expected to believe some random Azb guys over an eBay listing claim?

That's hexalobular.