Sixpack,
A few comments below:
sixpack said:
Colin,
I think this is an interesting train of thought, but I wanted to clarify a few things that I didn't think were clear enough in this or the BHE thread:
1) To be clear, BHE does NOT reduce deflection, it merely puts the error from deflection back onto the line of the shot. While it's true that hitting the cue on an oblique angle will reduce the time the tip is in contact with the cue, that actually doesn't make it deflect LESS, it makes it deflect MORE. The more obliquely you hit it, the more it deflects back to the line of the shot if you hit it with center ball, thereby correcting itself. The correct pivot point for BHE is the point at which the deflection error = pivot error. This changes with different cues but is usually about 18 inches back from the tip. So it is not where your typical bridge might be although on shorter shots the margin for error is probably large enough to get away with this.
I agree, BHE is really an aiming system that compensates for the effects of CB deflection (squirt)...and can also compensate for throw and swerve if adapted according to a system.
I don't think the contact time point, as raised by Jaden is relevant nor proven...if it has been I missed it.
I doubt most pivot points are so far back. When my bridge gets to about 14 inches, with side, I notice the CB deviates right when struck with left side. At six inches, it clearly deviate left when struck with left side.
2) pure sidespine does not create swerve on the cueball. For there to be swerve, the shot must be struck below or above center. A ball struck lower left will swerve LEFT and a shot struck upper left will swerve RIGHT, at a much lower rate. I had to test this for about four hours before I believed it.
Swerve is produced on non-directional cloth my a vertical component in the spin. Hence, lower shots are more likely to swerve more. I think it is very hard to hit up into a topspin shot, but at least swerve should be less a factor on follow shots with side english.
I've never heard of follow with English swerving in the opposite direction. I doubt it, but I've been wrong before
3) By throw I am assuming you mean the effect of the cue ball on the object ball. This effect relates inversely to two factors, speed and angle, assuming the spin on the CB is the same. The slower the speed of the CB and the straighter the shot, the more throw is created. Hard shots have less of a throw effect and so you actually have to aim further outside to hit the OB to the point where you were throwing it to.
Actually, there is good evidence to suggest that the degree of throw increases for thinner angles.
See here...some good diagrams for this discussion:
http://www.engr.colostate.edu/~dga/pool/technical_proofs/new/TP_A-14.pdf
I think the effects you are seeing are the result of throw as you stated, but for pure IE and OE shots, swerve should not be a factor.
A lot of OE shots are played slow and with draw, (swerving becomes significant) and this does create a habit of aligning considerably thicker.
For combination of top/bottom side spin, I don't think moving the pivot point will work by itself, because as stated above, bottom and top create opposite swerve errors.
As stated above, there is clearly some difference, but opposite? I haven't seen this exact point brought up before.
What I do when I use BHE is adjust my contact point to allow for throw and swerve and and line up straight on that line then pivot. That way the CB is put on the path necessary to pocket the OB with the english imparted.
Thanks for the thought provocation.
As an aside, I recently was talking about this with a well-known professional. He told me that while BHE was okay, he never used it becaues if he lined up right and stroked well, (i.e. parallel english) didn't generate enough deflection to make him miss even long shots on a 4 1/2 X 9' table, even with tight pockets. His opinion was that BHE introduced more error than it cured.
After using BHE for a long time, I didn't believe him, but we spent an hour convincing me that it was true. Now I use either/or as the situation calls for and I make most everything no matter what english I need to use.
Cheers,
RC
I've said elsewhere that I don't believe their is any significant difference in where the cue and bridge get to for what is called parallel english and backhand english.
I'd like to see a diagram that shows two different bridging postions, same bridge length, with cues on different lines contacting the same OB at the same point (let's say two tips left), that could send the CB in the same direction.
It would seem to contradict the basic laws of physics as we understand them!
I think they are just different alignment methods that bring us to the same location. The only difference is the angle of the placement of the bridge hand.
I think BHE is a very useful and potentially accurate tool, but it needs compensation factors for such things including speed of hit, top or bottom, pivot point and possibly degree of side, humidity, cut angle and possibly more.
Potentially all these could be compensated for with an adjustment in bridge length, hence any shot could played by first lining up as a center ball hit with a bridge length pre-adjusted.
Colin
lol.) and unfortunately again, I'm stuck down here at GTMO till DEC so I can't try out any of this stuff while really paying close attention. I'll have some feedback once I get back and can start playing on some tables again.
