Dead Blow Cue

How hard are you pounding things into your vise? I have never used more than a 12oz deadblow on my vise and I don't swing it as hard as I swing my cue on a break.

Not all deadblow hammers are soft faced. Not all soft faced hammers are deadblow.
Sometimes hard all depends
If I can’t use a solid round of brass
It’s dead blow, sometimes I’ve used a piece of 2x4 with a round bar of brass if dead blow isn’t working
 
Does the McDermott Defy shaft act like a dead-blow hammer?

YouTube videos show wood shafts bounce when dropped on tip on pool table while the McDermott Defy carbon fiber shaft does not.

See 2020 AZBilliards discussion of the Defy carbon fiber shaft. It is described as a different and softer hit than other carbon fiber shafts.
The Defy on the other hand is by far the quietest, softest feeling CF that I found. As described by many others, it's almost like you can't feel the impact at all.

This softer hit and lack of vibration is similar to the effects of a dead blow hammer. The fact that a Defy shaft bounces off a pool table while other shafts don't suggests action like a dead blow hammer.

McDermott claims the different type of carbon fiber in Defy "consumes vibration". From McDermott description on Seybert's:

The Defy Shaft is equipped with the new SmacWrap technology previously designed for the aerospace industry. SmartWrap technology consumes vibration and softens the noise resulting in a confident, clean hit with excellent player feel and quiet sound.​
 
See 2020 AZBilliards discussion of the Defy carbon fiber shaft. It is described as a different and softer hit than other carbon fiber shafts.


This softer hit and lack of vibration is similar to the effects of a dead blow hammer. The fact that a Defy shaft bounces off a pool table while other shafts don't suggests action like a dead blow hammer.

McDermott claims the different type of carbon fiber in Defy "consumes vibration". From McDermott description on Seybert's:

The Defy Shaft is equipped with the new SmacWrap technology previously designed for the aerospace industry. SmartWrap technology consumes vibration and softens the noise resulting in a confident, clean hit with excellent player feel and quiet sound.​



Read about SMACWrap and you'll find it is nothing like a dead blow hammer. It is thin vibration damping material used between layers of cf. It is much more like the soundproofing in your car than a dead blow hammer.
 
I would hate a dead blow cue…..if you vary the length of your follow-through you get different effects.
 
You don't want a dead blow. A pro friend and I recently discussed moving with the shot, focusing particularly on spin shots.
 
Let's get something straight: A cue filled with moving weight/shot will not just stop when it hits the cueball. That isn't what a deadblow hammer does either. The purpose of a deadblow hammer is to reduce the shock of the impact. If the object hit by the hammer is able to move, it will move...and the hammer will move after the impact. The deadblow hammer is used for things mentioned earlier in the thread for the reasons explained. The shot in the deadblow hammer increases the time of impact for the hammer. This means that the impact force is the same for two hammers of the same weight/velocity, but the maximum impulse is lower with the deadblow.

Deadblow hammers are important safety devices, as described in other posts. They tend to not bounce off of immovable objects and hit a person in the head. They tend to reduce shock forces in the hands/wrists of the user (especially important when setting large machinery, using 10-20 lb hammers/mallets). They tend to protect equipment, not leaving dents/dings.

But, if you hit a moveable object with a deadblow, the object and the hammer both move after contact. An 18oz 'deadblow' cue will not magically stop because it hit a 6oz ball.

What that cue will do is have some really odd acceleration forces after the hit. As @Murray Tucker said, there is a reason that anyone who makes a shot-filled cue probably won't make another.

What possible advantage could a cue with moving weight have? The contact time between the cue and the ball is so short that all of the moving mass in the cue takes place after the hit. Effectively you'd get all of the disadvantages of a light cue (need more speed for same cue ball travel, etc) with all the disadvantages of a heavy cue (takes more effort to accelerate to a given speed).

All you really get if things work correctly is a heavy ineffecient cue that feels weird. Woo-effing-hooo.

But I'm done here, y'all keep going down your ignorant rabbit holes about a cue that will magically stop moving after hitting a ball.
 
Those of you who thought of this but failed, do you have your prototypes? Report or share your results? Publication of failure is an essential part of the process, right?
 
hose of you who thought of this but failed, do you have your prototypes? Report or share your results? Publication of failure is an essential part of the process, right?

Liquid Weight Cues, now Black Blade Cues, made cues for several years using the dead-blow hammer concept using ball bearings and, later, magnets. It has patents on it. The owner posted here recently (see link below). Forward your response above to him on AZBilliards.

An AZer liked the cues:

I used the first version of the liquid weight cue, it had a very interesting but not what I would call a bad hit. Actually enjoyed playing with it but decided not to buy one even though it was not expensive at all.
Hang-the-9 posted in post https://forums.azbilliards.com/threads/have-you-tried-cues-“black-blade”-“liquid-weight”-—-cues-that-use-a-movable-weight-system.564087/

The owner, Glen Farr, of Liquid Weight cues, now Black Blade, posted in October about his newer cues on AZBilliards:

He said this about the movable-weight cues now discontinued:
We no longer make the moving weight system. It was a great training tool but hard to actually play a match with.
 
Last edited:
My point is one discussed among certain academic researchers and publishers when evaluating an entire body of work. A lot of researchers, and perhaps even more publishers, prefer to circulate only the success stories The ventures taken down dead end rabbit holes lack appeal and as a result what they teach is often lost to posterity. When one is conducting initial research, being able to ascertain what has been previously tried but failed is often of equal value with the success stories. Both sinking and sailing ships provide jumping off places.
 
Last edited:
My point is one discussed among certain academic researchers and publishers when evaluating an entire body of work. A lot of researchers, and perhaps even more publishers, prefer to circulate only the success stories The ventures taken down dead end rabbit holes lack appeal and as a result what they teach is often lost to posterity. When one is conducting initial research, being able to ascertain what has been previously tried but failed is often of equal value with the success stories. Both sinking and sailing ships provide jumping off places.

Not really. Scientists and engineers have no moral or academic obligation to report or extensively test abject failures, unless those failures can cause grievous damage or injury.

My test on my shot filled cue was hitting some shots. It sucked, it felt horrible, it was noisy. There, that is my research and my conclusion.

There is the old saw about Edison being asked about his 1000 lightbulb failures. He replied that he found a thousand ways that didn't work. What they miss in the normal interpretation of this is that none of those 1000 attempts failed to create light. Most of them just burned up too quickly or didn't produce a usable quantity of light. Lest we forget, his first commercially successful lightbulbs lasted something like 20min.

You can try your own version if you want. You can commission some cuemaker to build one (I won't unless it is for enough money to retire).
 
Liquid Weight Cues, now Black Blade Cues, made cues for several years using the dead-blow hammer concept using ball bearings and, later, magnets. It has patents on it. The owner posted here recently (see link below). Forward your response above to him on AZBilliards.

An AZer liked the cues:


Hang-the-9 posted in post https://forums.azbilliards.com/threads/have-you-tried-cues-“black-blade”-“liquid-weight”-—-cues-that-use-a-movable-weight-system.564087/

The owner, Glen Farr, of Liquid Weight cues, now Black Blade, posted in October about his newer cues on AZBilliards:

He said this about the movable-weight cues now discontinued:

Sounds like Shake Weight missed their big opportunity to put their mechanism in a cue and not revolutionize pool in the same way they didn't revolutionize working out.
 
People looking for an improvement in cue stick design are often looking for a more "efficient" cue stick -- one that gets more speed into the cue ball for less effort in the stroke. If energy goes into something else, such as ball bearings sloshing in oil or some such, there is less energy to put into the cue ball.
 
Most of the advances I see were aimed at reducing deflection. Can deflection be further reduced? Does it need to be?
 
Regarding why McDermott's carbon-fiber Defy shaft (certainly its first generation shaft) did not bounce when dropped on table while other carbon-fiber shafts did? And why that shaft has a different and softer hit than other carbon fiber shafts?

Kling&Allen explained in his 2022 post copied below that according to McDermott's patent, the Defy shaft has absorbing material something like butyl rubber or, as DeeDeeCues wrote, SMACWrap used in the aerospace industry.

Read about SMACWrap and you'll find it is nothing like a dead blow hammer. It is thin vibration damping material used between layers of cf.

See 2020 AZBilliards discussion of the Defy carbon fiber shaft. It is described as a different and softer hit than other carbon fiber shafts.

Kling&Allen post from 2022:

My brother bought a Defy shaft. It’s really different. We took our shafts off and just dropped them tip first on the table. My Revo bounced up some inches. His Defy shaft just landed with a thud, no bounce at all. Is that a sign that it has better energy transfer or worse?

Here's the patent application on the Defy shaft:

It has a "kinetic energy absorbing insert" "made of a structural elastomeric material" like butyl rubber or "SMAC SMACTANE® SP Damping Material." At least in the drawings, this insert is in the middle of the shaft:

1662178098351.png


From the Revo teardowns I've seen, it's all foam filled. So this butyl rubber insert is the reason for the difference in feel. McDermott mentions this patent application, and SMACTANE, on its website, so the drawing is probably accurate.

For what its worth, I personally like using a long maple plug as the joint plug instead of a phenolic insert. I don't like the way the pin feels screwing into phenloic and the maple plug seems less tinky sounding than just phenloic and foam
 
You are thinking about this in the wrong way. To approach 100 percent energy transfer you want to maximize the axial impulse component and minimize the impulse time. This would mean using something with low compression and elastic properties, like a steel rod. But since the ball is round and deflection is a problem, you need to be perfectly accurate to center ball. This can be improved by making the face of the tip huge, like a golf ball driver. So you will have a battering ram type break cue that minimizes offset error. The cue should also have mass that optimizes the human acceleration to object mass curve to maximize energy input from your arm. I don’t know that 21oz is optimal.
 
Back
Top