Bridge Length

[AtLarge]

... 22" inches might be a couple of inches off. ...

Have you tried to determine the natural pivot length in the manner suggested in Dr. Dave's video: http://billiards.colostate.edu/threads/English.html#BHE?

I just tested the R360 shaft I own. The diameter at the ferrule is 12.7 mm. The natural pivot length is about 14 inches.

 

[Patrick Johnson]

...the pivot point is measure from the bridge V to the edge of the CB.

I measure pivot points from the bridge V to the tip of the cue...?

pj
chgo

 

[skipbales]

I measure pivot points from the bridge V to the tip of the cue...?

pj
chgo

Where would you measure from with a closed bridge? I am guessing the outside of the index finger although the cue is also resting on the center finger.

 

[Patrick Johnson]

Where would you measure from with a closed bridge? I am guessing the outside of the index finger although the cue is also resting on the center finger.

Not sure where the outside of the index finger is... I'd measure from where the cue rests on the middle finger, but anywhere within, say, 1/4" is probably accurate enough.

pj
chgo

 

[martind2112]

I went back to the table and I get pretty much the same results. I can't get the CB to squirt to the opposite side of the OB, regardless of bridge length, up to a very uncomfortable 23"! I.e. I apply right BHE, I always hit the right side of the OB (cut to the left), and vice-versa.

I've watched Dr Dave's testing procedure video again. On my previous trials I was hitting a slower, medium-firm speed as this is what I would normally use during play. Even then, I could not notice any swerve. Today, I hit them harder, like in the video.

I must be doing something wrong or different. I paid special attention to stoke in the line of the cue, post-pivot, and was careful not to steer or introduce "body english".

I'll give that a rest for now. I wasn't necessarily trying to evaluate the R360 shaft. My point was that BHE didn't cut it for me, but I've had success with FHE. I mentioned the type of shaft as I think it is relevant to this topic (even at the risk my Cuetec could be ridiculed ).

 

[martind2112]

I measure pivot points from the bridge V to the tip of the cue...?

pj
chgo

That would be accurate, if it is assumed that the set position is very close to the cue ball. If a player set his tip too far back, that would skew the measurement.

I think from V to back of CB covers all cases (close to not-so-close CB address). The pivot length takes effect when the tip actually touches the CB.

My 0.02$

 

[Patrick Johnson]

I measure pivot points from the bridge V to the tip of the cue...?

pj
chgo

martind2112:
That would be accurate, if it is assumed that the set position is very close to the cue ball.

It's probably easiest to place your bridge the pivot distance from the CB, but as long as the tip is pointed at the tip/ball contact point when the pivot point is at the bridge (i.e., the cue is on the correct line), then distance to the CB doesn't matter.

pj
chgo

 

[Colin Colenso]

I measure pivot points from the bridge V to the tip of the cue...?

pj
chgo

Ok, got ya.... when the tip hits the CB. Just pointing it out, because sometimes people don't measure, but guess, and perceive a distance from their fingers to the CB.

In relation to other comments in this thread, the pivot point within a bridge is a little trickier to determine on some closed bridges and between 2 fingers on the rail, but there is enough margin on error on most shots to get it right within an inch or so.

Colin

 

[skipbales]

Not sure where the outside of the index finger is... I'd measure from where the cue rests on the middle finger, but anywhere within, say, 1/4" is probably accurate enough.

pj
chgo

I was referring to the point where the cue passes through the curled index finger, the edge closest to the cue ball. Other possibilities might be the center of the curled index finger or the center or edge of the point where the cue rests on the middle finger. The total difference is only about 1/2 inch so probably isn't significant. I wish I were accurate enough that these things were what made the difference, mostly I am just curious.

 

[Colin Colenso]

I went back to the table and I get pretty much the same results. I can't get the CB to squirt to the opposite side of the OB, regardless of bridge length, up to a very uncomfortable 23"! I.e. I apply right BHE, I always hit the right side of the OB (cut to the left), and vice-versa.

I've watched Dr Dave's testing procedure video again. On my previous trials I was hitting a slower, medium-firm speed as this is what I would normally use during play. Even then, I could not notice any swerve. Today, I hit them harder, like in the video.

I must be doing something wrong or different. I paid special attention to stoke in the line of the cue, post-pivot, and was careful not to steer or introduce "body english".

I'll give that a rest for now. I wasn't necessarily trying to evaluate the R360 shaft. My point was that BHE didn't cut it for me, but I've had success with FHE. I mentioned the type of shaft as I think it is relevant to this topic (even at the risk my Cuetec could be ridiculed ).

The way I've learned to best determine a cue's pivot point is as follows:

Place OB 1 foot from the corner pocket. Place the CB 4-5 feet away from it, in a straight line along the diagonal of the table (this provides enough distance to show up squirt errors, allows a pretty flat stroke as hand is on the table, not the rail and reduces the potential for swerve.)

Align to pot dead straight. Hit a few straight center ball shots to get your eye in for correct alignment. Then align the same, fix bridge solidly and pivot left with cue tip to near miscue point, touch below center and shoot as hard as you can with control.

Repeat this, varying bridge length until you're making the shot near center pocket most of the time. Then do the same alignment and pivot the cue to the right, which after a few attempts, using the bridge length that worked on the left pivot, will soon confirm if your at your pivot point, or if your alignment has been out.

This low res video I made years ago, which I hope to re-do some day soon, may help to get a grasp of the topic:

https://www.youtube.com/watch?v=ERFTM8dbat0

Colin

 

[DeadStick]

I mentioned the type of shaft as I think it is relevant to this topic (even at the risk my Cuetec could be ridiculed ).

Hey, if it's good enough for Shane you won't find any knockers on here. I've heard nothing but good things about them.

I'm going to re-measure my Z2 pivot point as per Colin's instructions in a few days. Waiting on my new (to me) Centennial to show up. All I'm sure of is that I use a bridge distance of around 13" and a ton of BHE and the CB goes where I originally aimed. Perhaps I'm fudging my bridge over a tad without realizing it.

 

[Colin Colenso]

Hey, if it's good enough for Shane you won't find any knockers on here. I've heard nothing but good things about them.

I'm going to re-measure my Z2 pivot point as per Colin's instructions in a few days. Waiting on my new (to me) Centennial to show up. All I'm sure of is that I use a bridge distance of around 13" and a ton of BHE and the CB goes where I originally aimed. Perhaps I'm fudging my bridge over a tad without realizing it.

I still unintentionally fudge my bridge sometimes when tired or a tense. There seems to be a part of the brain that wants the bridge to drag the cue's alignment back toward the OB.

It can take some time, and even a few hand cramps to train oneself to lock the bridge solid throughout the pivot.