I have a somewhat technical question about mass bias location. With Mo's Dual Angle Drilling Technique (see http://www.morichbowling.com/MosCorner/DualAngleSeminar/DualAngleSeminar.htm) the Drilling Angle determines the location of the mass bias relative to the Pin and PAP. However, all I am getting from the documentation concerning its effect is:
A 10° drilling technique will roll the soonest of all the effective drilling angles.
A 90° drilling technique will roll the latest of all the effective drilling angles.

Other sources (see http://www.bowlingfans.com/jeff/ballreactionbasics.html and http://www.tunedballmotion.com/Layout.htm) suggest that the actual location of the mass bias relative to the Track and VAL determine its effect.

Using Mo's system, you can use different Angles to the VAL (for example 20/45/70 degrees), and use the same Drilling Angle (for example 90 degrees), and wind up with the mass bias in different locations relative to your Track and VAL.

Further, other sources suggest that the center of the range, not one extreme or the other produces the strongest reaction. Recently I drilled up a ball with a 45% Drilling Angle that wound up around equidistant from my Track and VAL, and sure enough, it has a much more angular breakpoint shape than expected.

Is this a flaw in Mo's system or documentation? Is the actual position of the mass bias between the Track and the VAL more important than the somewhat relative Drilling Angle?

First, What the ball does depends on coverstock ,lane condition, mass bias strength and release.

On your 45 deg mass bias ball.. what is the pin to pap and pin to VAL distance?? That is going to play a big part to what the ball does

From my reading and experimenting I believe the mass bias distance from PAP is what determines what it does. The angle is just a way of describing it.. I am personally beginning to like the #" x #" #" pin buffer way of describing a layout.

going with the degree terms 60 degree seems to be the best for me for backend and use it with a longer pin for my skid Flip layouts.. I've tried 70 and its to long.. and tried 50-55 and its to smooth.. a 45 deg mb Cell for me was way too smooth and the ball had zero backend or recovery.

I agree that there are several factors, and mass bias may be less important than the others, but after [re]drilling about a dozen Cells, Pearls, and Rogues, I am beginning to see the difference the mass bias makes.

To answer your question, the final specs for the ball mentioned was 4.5 x 4.5, Pin above the fingers, or in Mo-speak, 45 degree angle to the VAL, 4.5 inches pin to PAP, and approximately 50 degree drilling angle. I say approximately because I made an adjustment for the mass bias to be exactly 4.5 inches from PAP. I also drilled a balance hole 6-3/4 from the Pin on my VAL. The end result for static weights was 3/4 positive side, 3/4 finger, and 1/2 bottom. The last thing I did was sand the surface to 1200. I was hoping for an intermediate or "benchmark" reaction, but it is definitely more angular than other Cell/Pearl/Rogues I have drilled with more like a 90-degree Drilling Angle.

Before somebody jumps in and suggests sanding, polishing, or making some other change to this ball, please don't, that is not the intention of this thread. I just want to get to the bottom of how the mass bias, in general, can be used to influence the ball reaction, and identify the best way to describe the angle/location. It seems that Mo's Dual Angle Technique does not provide a good way to do either.

not going off on a sanding tangent but if you took it to 1200 grit ansi that is going to make the ball way more snappy on the backend then out of the box.. If you left it at out of box I imagine it would be a ton smoother ..That weight hole is increasing the flare also.. which in some cases increases backend..
I would agree with you that 90 degrees is not the best for snap or Flip on the backend unless you have tons tons of hand.. maybe..
like I said.. 60-65 is the max I would go..
I know this isn't the proper way to look at it but the best look I have is with the MB about an inch to the right of the thumb hole.. anything closer to the pap or val line the ball gets smoother and earlier for a given PAP..

I like that mini ball reaction guide.. some good basic info.. a little dated but good..

check this out.. This kind of shows 75 deg as the mid point. who knows what is the absolute truth.. I have been trying to find out for some time but everyone just spits out the same info over and over like they did for the "pin at 1 oclock" cr*p for the last 50 years until someone finally scientifically figured out that it was the pin to pap distance that was changing what the ball did..

http://www.bowling-info.com/index.php?template=FAQ

AFFECTS OF MASS BIAS (MB) PLACEMENT back to top
As the angle goes from 75° (strong/Flip) to 0° length will be reduced and have more of an arc reaction. From 75° to 105° lenght will increase and have more of an arc reaction. Beyond 105° the reaction will keep a very similar reaction but with more length.
Remember : These only enhance the characteristics of the given ball and Pin placement and the Flip (strong) position may not necessarily have the biggest backend reaction on given condition due to many other variables that affect ball reaction (bowlers specs, lane condition, etc.)

also on that tuned ball motion site I would have to disagree with their pin migration explanation but the MB explanation kind of goes in line with what you are talking about and what I would agree with..

Briefly, concerning sanding, I use a range of 320, 600, 1200, 2000, and 4000. So, 1200 is middle of the range for me. When I want earlier and smoother hook, I go towards 320. When I want later, more angular hook (skid/Flip), I go towards 4000.

Back on the mass bias topic, I think you make some good points, and your experience concurs with mine. I think maybe Mo's documentation could be updated to say:
A 10° drilling technique will roll the soonest (arc) of all the effective drilling angles.
A 45° (or 75°, or whatever is the "magic number") will Flip the most of all the effective drilling angles.
A 90° drilling technique will roll the latest (arc) of all the effective drilling angles.
That would have been helpful when I was mapping out the ball to know the middle of the range would not produce an intermediate reaction, but a sharper reaction.

Still, where the mass bias actually winds up with Mo's system is dependent not only on the Drilling Angle, but the Angle to the VAL, and the Pin to PAP. I am thinking there may be a better way to describe the Mass Bias Location, perhaps as an Angle to the VAL, and distance from the PAP, similar to the Pin location?

to confirm.. 1200 is abralon FEPA standard or US Cami standard ??

if 1200 abralon disregard my previous post about the grit..

sorry for the sidetrack

No problem. I am not sure which grit standards these match up to, but below is what I use:
320, 600, 1200 - Taxi cab blocks
2000 - Wet/Dry Sandpaper (I think it is silicon carbide)
4000 - Abralon

that is why I like the say.. 4.5" x 4.5" with a 2" pin buffer.. you tell someone that and they can lay a ball out for anybody and it should have a similar reaction or atleast the potential for a similar reaction..

the pin to VAL (or pin height) really affects the backend reaction as well..

From what I have learned this is the order of ball reaction influence.

Cover /lane condition match up
Release
pin to pap
(still a toss up on Pin to VAL(or actually PIN in relation to the weight taken out of the core by the finger and thumb holes) or MB location)

ok.. not sure of the standard on the taxi cab blocks.. .. I think ansi..
Not sure if you are aware.. Abralon uses a different standard than US standard sandpaper..
this site has the best grit chart around..

Abralon is the FEPA "P" standard ..

1200 ansi US is a little finer than 2000 Abralon.

If that 2000 is ansi it is finer than the 4000 abralon

http://home.earthlink.net/~litefrozen/downloads/bowling_grit_chart.pdf