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Author Topic: Unofficial FAQ Section (repost)  (Read 96389 times)


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« on: January 28, 2005, 11:34:16 AM »
Updated 01 Nov 09.

Since there are many that feel that we need a FAQ section I decided to start one in the form of a post that will hopefully end up as a permanent part of the site.
I will add more as time allows and questions arise.
If you have anything that you think should be added please post and I will add it. I do already have additions in mind though, it sure would cut down on my typing and would be greatly appreciated.

Once I have added your post please delete or PM them to me so we can keep this tidy THANKS


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Bowlers specs(see "Bowler Specs" section to determine)
Axis tilt.
Axis rotation.
Weight (Pre-drill.)
Top weight (Pre-drill.)
Pin to CG distance.
Surface prep.
Pin to PAP distance and Pin to grip center distance.
CG to PAP distance and CG to grip center distance (up/down).
MB (either premarked or measured) to PAP distance and MB to grip center distance.
Clock or ° of drilling (see "Drilling" section).
Balance hole location, size, and depth.
Post drill weights (top/bottom, pos/neg side, finger/thumb) if known.
I prefer to use a comparision to another ball or balls for this, because what one may consider heavy oil may be medium oil to another and vise versa.
List the length and type (tree, top hat, etc) of the pattern if known.
Lane material synthetic, wood, combination.
Line being played
Arrow board/Break point board @ x ft. (Examples: 15/5 @ 45 ft, 10/6 @ 45ft)
Again this is a good time to use a ball comparison.
Ball path shape
Backend Flip, Strong Arc, Arc, etc.
Midlane Straight very little midlane read, Late midlane read small move, Early midlane read strong move, etc.

I list this as a guide line in hope that we can cut down on the "ball good, hook big, hit like nuclear warhead, get 1" reviews that have been popping up at an alarming rate lately, because they are of no use to any of the members of this board except for a laugh.

Internal or core torque refers to the mass distribution within the core and the internal lever arms created by the core. Core torque is an assigned value of the balls ability to combat roll out, the complete loss of axis tilt and axis rotation. High torque balls are more effective than lower torque balls at delaying roll out. Core torque can also be one indicator of the type of reaction that a bowler can expect at the breakpoint with high torque balls having the propensity to be more "violent" and the lower torque balls tending to display a more even, predictable transition from skid to roll.
It is the difference between the lowest and highest RGs. You compute the high and subtract the low from that and you have the differential. There is no minimum for differential. What differential tells you: RG Differential is an indicator of track flare POTENTIAL in a bowling ball. Differentials in the .01s to .02s would mean that a ball has a lower track flare potential, .03s to .04s would be the medium range for track flare potential, and the .05s to .080 would indicate a high track flare potential. These ranges above are not based on cardinal rules. They are BTM in-house rules of thumb because there are no published guidelines.

Also, differential is a guide to the internal versatility of a ball. It can indicate just how much of a length adjustment can be made through drilling. A low differential will allow for only a modest variance in length (from shortest drilling to longest) which may translate into as little as a foot or two. An extremely high differential may translate into a length window in the neighborhood of eight feet.

The planned apparent imbalance in balls due to high tech cores and drilling techniques. Many people claim that this has created balls that hook out of the box with a lessening requirement to have the skill to impart the hook and power by the bowler themselves.

In the old days, before the advent of modern core design in balls, the center of the ball was, more or less, symmetrical. In todays high tech computer designed ball cores and multiple cores designs, you can have cores that are not evenly balanced and distributed within the center of the ball this allows balls to be drilled and designed in a manner that the apparent "weight" of the ball can shift depending on the drilling pattern i.e., it is not "static" it is "dynamic".

The migration of the ball track from the bowlers initial axis, the axis upon release, to the final axis, the axis at the moment of impact with the pins. The more flare created by the core the more hook potential for given coverstock.

Simply put, the mass bias in a bowling ball occurs when the mass (weight block or portion of weight block) is bias (more dominant) in one direction inside of an object (in this case a bowling ball). If you took a bulb shaped, single density core and positioned it dead center from side to side inside the ball, there would be no mass bias. You also would have a ball that is a pin in.

In order to kick the c.g. away from the pin to create a pin out ball, you have to "tilt" the core inside the ball, or place the entire core slightly off center. This became a common practice among manufacturers as the demand for pin out balls increased. When this is done however, you create a "dynamic imbalance" inside the ball because the mass is more dominant or "bias" in the direction of the "tilt" or "offset". That is the most important factor when discussing the mass bias, it is a DYNAMIC POINT ON THE BALL. Positioning the mass bias in different positions when laying out a ball will have a great impact on the "motion" the ball will make as it is going down the lane (even arc, hook/set, skid/flip and so on).

There are people who will argue that static imbalances (finger weight, side weight etc) are more important than dynamic imbalances. My reply to that, is that a dynamic imbalance is a real point in the ball, it is constant and does not change unless you alter it by drilling into it with a drill bit. A static imbalance or the c.g., will change as soon as you put one hole in the ball. It will change again with each additional hole you put in the ball as well. While static weights can be used to "fine tune" the reaction of the ball at the break point, it is the dynamic lay out that dictates the roll of the ball. If a pro shop operator truly understands the principals of the mass bias and how to apply them, they can greatly increase your overall satisfaction with the ball you purchase.
On a ball that does not have a premarked MB its theoretical position can be found by measuring from the pin through the CG 6.75".

A Pin-in ball (when the pin is located within two inches of the CG) is excellent choice for control and less hook a Pin-out ball usually can be made to hook more and flip more dramatically than pin-in balls they often give the driller more options.

This is the final position of the axis after the ball has lost all axis rotation and tilt. The length of time it takes for the ball to reach its PSA and its post drilling PSA are influenced by the amount of friction, the drill layout, and bowlers specs.

The measurement that tells us the cores impact on the skid potential of the ball. "Identifies how fast a ball begins to rotate once it leaves the bowlers hand. Three designations for RG balls are low, medium, and high. A high RG ball goes longer because it takes longer to begin rotating and stores its energy on dryer conditions. A low RG ball revs up early and is a more evenly arcing ball used on wetter conditions. There are three axes on a bowling ball used to measure RG (radius of gyration). The lowest RG axis (usually denoted by the letter Z) is the axis through the pin. The highest RG axis (usually denoted by the letter X) is located 6-3/4 inches from the pin through the center of gravity (CG or heavy spot). The intermediate RG axis (usually denoted by the letter Y) is located 6-3/4 inches from both the low and high RG axes.

Even though all bowling balls of a given weight are about the same size (minimum diameter of 8.500 inches to 8.595 inches), these balls are constructed differently. Some use two materials (one shell and one core), others use three or four or five or more pieces to construct the shell(s) and core(s)
Each of the materials used has a density (which roughly translates into weight per unit of volume). Zirmonite (as used in the Columbia pin) is denser (heavier by volume) than Bismuth Graphite (used in the core of the Brunswick Zones) which is denser (heavier by volume) than the fired ceramic that is used in the Columbia and Track cores. These and the other dense-material cores used by other manufacturers are all heavier by volume than the material used in the main cores. The main core material is denser than the foam-like material used as outer cores or inner shells, the purpose of which is to keep some balls in compliance with the ABC/WIBC weight limitation and to help pinpoint a certain RG value. Then there is the urethane used for the outer shell of the ball which by density fits in between the core materials.

Even though you may have a bowling ball with as few as two parts or as many as five or more, all balls have one characteristic. They will act as if all of their weight is located at a point some distance away from the rotational axis. This distance is the radius of gyration (RG). For example, a bowling ball has a maximum allowable diameter of 8.595 inches (maximum radius = 4.2975 inches). Theoretically, the RG could be any distance from just over 0 inches--by placing ultra-dense materials in the center of the ball and extremely lightweight filler beyond--to just under 4.2975 inches by placing ultra-dense materials near the outer shell and filling the inner areas of the ball with lightweight foam.

In the first example, the ball would be as center heavy as possible. In the second, it would be as shell heavy as possible. The problem with unlimited RG is that the two extremes would produce variations in ball performance that would be enormous. One would roll immediately and the other would "lope" all the way through the pin deck.

The ABC/WIBC, in an attempt to limit the amount of variation in ball performance that could be achieved through construction, placed minimums and maximums on RG. The rule states that the minimum RG can be no lower than 2.430 inches and no greater than 2.800 inches. This means that every ball must act as if its entire weight (mass) is rotating at a distance of not less than 2.430 inches or more than 2.800 inches from the axis. Since the total span of RGs ranges from 0 to 4.2975 inches, technically all bowling balls fall within the overall medium RG range. However, when anyone in bowling talks about RG, they are not referring to the total range of possible RGs, but instead only to the RG range allowed for the sport--2.430 to 2.800.

In the At a Glance chart and in ball reviews and comparisons in BTM, the following scale is used for low flare potential balls:

Low RG = 2.430 to 2.540
Med RG = 2.541 to 2.690
High RG = 2.691 to 2.80

There is a slight upward adjustment for high flare potential balls. Determining the RG: For BTM fellow ball geeks, the formula for finding the radius of gyration (usually denoted by the letter k) is: the square root of the balls moment of inertia divided by its mass (k-squared = I / m)."* What RG tells you: Like with everything else in bowling, RG--in and of itself--tells you very little. It is ONE indicator of length. The characteristics of the three types of balls are as follows:
A low RG ball will be easier to "rev up" and it will rev faster quicker because most of the mass is located relatively close to the center of the ball. Since it revs faster sooner, it also wants to hook sooner. Medium RG balls are intermediate-length balls. They are a little more difficult to spin (takes more power) so most bowlers will see a slight loping characteristic through the heads and early midlane followed by a faster revving action and later hook--than you would get with the low RG ball. High RG balls are the hardest to rev up since the mass is concentrated farthest from the center and therefore bowlers will see longer lope, much later revving up, and the latest hook from these balls.


Full Roller: Goes between thumb and finger holes
High-roller/High-tracker: Within a half inch or sometimes hits the thumb
Semi-roller: .5 to 3 inches
Low-roller/low-tracker: 3 to 5 inches
High-spinner: 5 to 7 inches
Low-spinner: more than 7 inches

NOTE: Above is a generalization and does not work in every case. You should still measure your track diameter.

In terms of rev rate (less to higher revolutions):
Stroker - Tweener - Power Player (can be power stroker or cranker)
In terms of wrist and elbow manipulation (less to higher):
Stroker - Tweener - Cranker

From Brian Pursel: Product Manager, Ebonite
RPMs, or revolutions applied, is the speed of the revolutions. The faster the revs, the greater the turning force is at the breakpoint. To measure RPMs you will need a low flare ball (spare ball is good), a piece of tape (4 to 6 inches long), and a video camera. Place the piece of tape running from the bowlers PAP to above the fingers. Film from behind, with a close up of the hand at the release point. As the ball is being released, stop the tape. Assign the tape a position on a clock (i.e. the piece of tape points to 10:00). In slow motion, click off 10 frames and freeze. Count the amount that the tape rotates as hours, as if it was the hour hand on a clock. Multiply the amount of hours by 15. (For example, the ball started at 10:00. After 10 slow motion frames the tape ended at 5:00, passing 10:00 once). One complete rotation around (10:00 to 10:00) counts as 12 hours. 10:00 to 5:00 (the ending position) equals 7 hours. This is a total of 19 hours of rotation. Multiply the amount of hours (19) by 15. This equals 285 Rpms. The other way to measure revolutions is called hand revs. You will also need the piece of tape and a video camera for this. Repeat the steps for measuring RPMs, however let the ball travel 15 feet down the lane. This is the distance of the fourth arrow. Note the starting position of the tape and count the amount of times the ball has rotated using fractions, not hours. Take the total amount of rotations and multiply by 4. This equals hand revs. For example, the ball started at 9:00 and ended at 3:00, passing past 9:00 three times. This would result in 3 1/2 rotations. 3 1/2 X 4 = 14 hand revs. Why do we not count the total amount of revs the ball rotates all the way down the lane until it hits the pins? Because friction will slow down the ball speed and create additional revolutions. By using the first 15 feet, we are counting the rotations in the presence of lane oil, a very low friction environment. In our Surface Friction Selection Chart, we use hand revs rather than RPMs.

The point that your PAP is facing at release (facing gutter 0° facing foul line 90°). Higher degrees of Axis Rotation promote skid and delay ball reaction.

The vertical inclination of you axis at release. This can be determined by measuring your track diameter (for every 1" < 13.5" = 6 2/3° of tilt). The less axis tilt you have, the sooner the ball will go into a roll. Higher degrees of axis tilt promotes skid. Being able to change your axis tilt using your release style is a very important tool in your scoring arsenal and in your ability to be able to play the lane condition.

The axis of the ball during the first few revolutions that is created totally by the bowlers release style. The point on the ball that is equidistant from all points of the release ball track.

Ways to find it:
Least accurate: Draw a perpendicular (90°) line 6.75" from your track through grip center the end of the line will be close to your PAP.
Very accurate: Use an Armadillo Axis point locator tool. Place the Armadillo on your track using the line that most closely represents your track arc and mark the spot indicated by the Armadillo.
Exact: Roll low flare (spare) ball down the center of the lane where the highest concentration of oil is then using a grease pencil trace your track. Place the ball in a spinner with the track down and orient the ball to where when it it spinning the trace line does not wobble up and down. Then take the pencil and place it on the top of the ball and move it around until it goes from making a circle to a defined dot, or use a quarter scale/pro sect tool and draw a line connecting your track at points that are 180° from each other and repeat the step at a point near 90° from the first line where the 2 lines intersect is your PAP. If you do not have a low flare ball you can use any ball as long as you use the track that is closest to your thumb and farthest from your fingers. This is the release track, because as a ball flares the track migrates away from the thumb and towards the fingers.
If anyone would like reasons for why one is more/less accurate than the other I would be happy to explain.

The number of times the ball rolls over its axis in the first part of the lane before it encounters friction or starts to migrate towards its PSA. Usually converted into Revolutions per Minute.

This is the total number of times the ball rolls over its axis from the point of release to the pin deck. This is not as accurate a representation of revs because it can be influenced by when the ball goes into a roll and the bowlers speed.

With a stop watch check the time it takes from release to head pin. I suggest at least five times to get a more accurate average.
40.91 divided by ave/time = MPH


All L/R pitches are from a RH point of view when referring to soreness.
When referring to L/R for fingers and thumb it is when looking at the back of the hand.

Thumb Pitches:
+ Reverse = Earlier thumb exit, increased grip pressure may be required, possible soreness to the front or back of the thumb.
+ Forward = Later thumb exit, reduced grip pressure may be required, possible soreness to front or back of the thumb.
+ Left = Reduced axis rotation, possible soreness to right side of the thumb at the base and left side at the tip.
+ Right = More axis rotation, possible soreness to the left side of the thumb at the base and right side at the tip.
Finger Pitches:
+ Reverse = Less lift, earlier finger exit, reduces rotation, possible soreness to the pad side.
+ Forward = More lift, later finger exit, increased rotation, possible soreness to nail side, or broken blood vessels under the nail.
+ Left = Axis tilt enhancer if all pitches are biased left from your normal pitches, possible soreness to right side of finger tip.
+ Right = Possible soreness to left side of finger tip.
+ Span = More loft, more axis rotation, more reverse required, possible soreness thumb tip nail side, thumb base away from nail, blood under thumb or finger nails, finger pads.
- Span = Less loft, less axis rotation, more forward may be used, possible soreness at the crease of first knuckle on fingers away from nail, thumb knuckle nail side, blood under thumb nail (clipping), thumb side away from palm.

With your thumb fully inserted into the ball lay your fingers across the finger holes the midway point between the first and second knuckles should be even with the edge of the hole closest to your thumb.

Drilling middle finger fingertip while drilling ring finger conventional.
Mostly used by power players to get more consistent release, cut down some revolutions and sideroll.

This test is used as a starting point for finding your ideal Lateral Thumb Pitch. If you do not have a Coke bottle you can also use your no bowling forearm/wrist by placing your hand around the point on your arm to where your thumb almost touches your fingers.
Index finger = 1/8 lateral away from palm
Between Index and middle = 0
Middle = 1/8 lateral under palm
Between middle and ring = 1/4 lateral under palm
Ring = 3/8 lateral under palm

Pin to PAP distance:
0" - minimum flare potential, core is in its most stable position, earliest roll with smoothest arc.
1 1/8" - 1/3 of flare potential, stable core position, earlier roll with smooth arc.
2 1/4" - 2/3 of flare potential, semi stable core position, early roll with strong arc.
3 3/8" - max flare potential, most unstable core position, medium length with the most hook potential.
4 1/2" - 2/3 of flare potential, semi stable core position, late roll with flip/arc reaction.
5 5/8" - 1/3 of flare potential, stable core position, later roll with a flip reaction.
6 3/4" - minimum flare potential, stable core position, latest roll with strongest flip.
Remember : These reaction characteristics are all relative to the conditions they are being used on and may not perform as expected due to burning up too early or not setting up early enough.
Pin to grip center (GC) distance: The higher the pin above grip center the more length you will get for given pin to PAP distance. The placement in relation to GC also affects where the tracks of track flare intersect (bow tie). Higher pin = Higher intersection. For this reason they suggest high trackers place the pin higher above GC to reduce the risk of flaring over the finger holes.

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° length 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.)

The degree system of drilling a ball is when a drill pattern is described or laid out by using the relationship between the angles of the lines from PAP to Pin and Pin to MB.
Examples: (A=PAP, P=Pin X=MB)

P-A-X is 0°      P-A is 45°    P-A  is 90°   P-A is 135°   X-P-A is 180°
                  \            |            /
                   X           X           X

These are obviously not exact but they are good enough to get the meaning across.

This system does not use the PAP for reference when describing the layout other than in pin to PAP distance, it uses the relation between Pin and CG or Pin and MB. Pin is the hour hand and CG/MB is clock center.
Example: Pin on bridge line and CG/MB swung at out 45° to the right would be a 10:30 drilling, Stacked=12:00, 45° left swing = 1:30, etc.
This system does not give as accurate a description as the Degree System IMHO.

Angling of the thumbhole or finger holes where the bottom of the hole is pointed toward the center of the grip.

Angling of the thumbhole or finger holes where the bottom of the hole is pointed away from the center of the grip. It is used to help the thumb exit sooner although very common, too much can cause the ball to fall off the hand early and may require increased grip pressure.

Left is when the bottom of the hole is biased toward the left side of the ball.
Right is when the bottom of the hole is biased toward the right side of the ball.
Used to assist in the exit timing of the ball (i.e. how fast or easily it comes off your hand) improper lateral pitch can cause blisters or sore spots on your thumb or fingers.

A drilling pattern with the Center of Gravity located on the bowlers P.A.P. and the pin in the leverage position.

It is a drilling pattern with both the pin and the cg located 3-3/8" from the bowlers P.A.P., usually requires an extra balance hole.


The heaviest part of a bowling ball. The CG is signified by a dye mark placed on the ball by the manufacturer designating the center of the weight mass relative to the top of the ball.

NEGATIVE WEIGHT (thumb, bottom, negative side)
Weight on a ball that tends to hold back the hook and/or to get the ball into a roll earlier bottom weight, negative side weight and thumb weight are considered negative weights.

POSITIVE WEIGHT (top, finger, positive side)
Weight on a ball that tends to enhance the hook and/or to get the ball into a roll later down the lane top weight, positive side weight and finger weight are considered positive weights.


These are the methods that I use
4 Step:
1. Holes facing up, sand for 30 seconds
2. Rotate the ball 180° to where holes are facing down, sand for 30 seconds
3. Rotate the ball 90° , sand for 30 seconds
4. Rotate the ball 180°, sand for 30 seconds
6 Step
1. Same as 4 step
2. Same as 4 step
3. Same as 4 step
4. Same as 4 step
5. I use this step when I am trying to get a small length change because 1 grit smoother or courser is too big a step. I  base the ball position off of my track and the desired change
More length – sand parallel to track
Less length – sand perpendicular to track
6. Rotate the ball 180°
I find that using these 2 extra steps works better for me, when I use a bit of polish with courser grit, for slightly less length or with the current grit for more length, it becomes harder to replicate the surface.
I use the same ball positions as in my 4 step sanding method. I start by polishing for 30 seconds per step and adjust from there for desired reaction. If I need to remove a small amount of polish I use a white scotch bright to achieve the slight dulling affect.

I recommend cleaning after every session with any of the ABC approved cleaners and giving the ball a deep cleansing once a month using the soaking technique. I use Simple Green, Orange Clean, Purple Power, etc (diluted 4 parts water to 1 part cleaner) for deep cleansing. I prefer these cleaners over regular dish soap due to their increased degreasing properties.
I also prefer “Ball” cleaners for every session use due to the fact that buying actual ball cleaners helps to support the sport.

What it is
Docs Magic Bowling Ball Elixir has been accepted for use before or after ABC/WIBC sanctioned league events. The Elixirs main purpose is to slow down and virtually eliminate oil absorption into todays new high tech expensive coverstocks. This is accomplished by a chemical process that does not affect the overall performance of the coverstock. It allows all coverstocks to function as they were intended whether Particle, Reactive Resin or Urethane. Whether the coverstock is polished or dull the Elixir adds performance. Other benefits that bowlers are seeing are that the bowling balls are absorbing less dirt and cleaning becomes much easier and faster. Some bowlers are also noting that the ball gets through the heads cleaner and that they are experiencing some added length and stronger backend reactions. Wiping the ball after each frame with a towel takes off virtually all the oil and the ball has that just cleaned feeling. Belt marks and pinmarks come off much easier as well.
So how does it work?
The Elixir does this by chemical bonding with the coverstock and does not allow the oil to permeate into the coverstock. The coverstock is allowed to perform the way you expect it whether dull or polished.
Some products on the market offer increase hook potential and others increase length but they do so at a price. Increased hook usually means the balls become tacky and everything sticks to them, dirt, belt and pin marks and the cover needs excessive cleaning and resurfacing. Energy is used up early as well and if the ball recovers it hits flat. Increased length means the balls surface has no surface friction to grab and the result is the oil from the lane sticks to the surface of the coverstock all the way down and is not shed so late or no recovery is the result. The Elixir creates length with recovery and here is how. Special chemicals in the Elixir allow the the ball to skid in the heads when it first contacts oil. This creates length. The ball also revs up faster because of lower surface friction. This allows the ball to gain momentum in the front part of the lane without losing too much energy. When the ball reaches the midlane and starts to roll it begins to shed the oil from the surface because oil does not stick to the Elixir. This keeps the balls surface drier and this helps the ball grab the dry on the backends. This is what creates recovery. So with the increased energy retention the ball carries pins better. Bowlers also notice that because less oil is being picked up on the ball they need to adjust their lines less frequently and cleaning is just a matter of a wipe away.
Application of the Elixir is a very simple process. Although starting with a new ball is probably the best way it is not necessary. First clean the ball to remove as much oil from the coverstock. This is a very important step. This can be done by a variety of means. Most people use commercial products on the market. Although Docs Magic does not endorse other products or cleaning methods many customers have had good results with the following. Neotacs Renew-It, Hook-It, Simple Green, Tracks Clean n Dull and Dawn Dishwashing detergent to name a few. Once clean and the ball is dry prepare the coverstock as you prefer to bowl. It does not matter whether the coverstock is dull or polished. The Elixir will not change the surface. Get a clean piece of paper towel and apply a small amount of Elixir to the towel. Remember a little goes a long ways. Rub the ball in a circular manner and be sure to cover the ball thoroughly. Some coverstocks absorb the Elixir quickly and others take a while to absorb. Wait at least twenty minutes before trying to bowl as to let the Elixir bond and dry to the coverstock. Even though the ball may seem dry almost instantly in some cases wait the full twenty minutes for best results. In some cases a second coat will be necessary after twenty minutes especially on some of the more porous particle coverstocks. A good test to see if the Elixir is working is to drop a spot of light oil as in 3 in 1 or a vegetable oil on the ball and it should bead up. Blowing on the drop should make it shed off and even trying to rub the oil into the ball it should not absorb. This is a good test to see if reapplication is needed. The Elixir can be applied with a ball spinner but this is not necessary and does not make the Elixir any more effective.

GRIT GRADING   (Courtesy of Charlest)

There are 2 basic ways of grading abrasion levels, CAMI and FEPA. CAMI is what has been used in the United States for many years. CAMI is an association of American Abrasive Manufacturers: Coated Abrasives Manufacturers’ Institute. FEPA is basically a newer standard used by European manufacturers, including Mirka, the inventor and manufacturer of Abralon, Abranet and associated abrasives. FEPA is an equivalent organization: Federation of European Producers of Abrasives.

The FEPA standard actually produces/requires a more consistent sized abrasive within any one specific grit level. The sizes of the abrasives in any one grit, meeting FEPA standards, fall with a narrower range of minimum and maximum for any one grit level.

Most American manufacturers have already begun to make their abrasives under the FEPA standard. So when looking for items, like sandpaper, be sure to check what the number printed on each piece of sandpaper represents before purchasing.

GRIT NUMBERS   (Courtesy of Charlest)

Normally, the grit number is a 2, 3, or 4 digit number representing the abrasion/roughness level of the abrasive on the material (paper, cloth, woven nylon, pads, etc). We are used to seeing numbers like 100, 150, 180, 220 grit for woodworking and numbers like, 320, 400, 600, 800 and 1000 grit for bowling specific needs. These have been CAMI graded or US grit numbers.

To separate CAMI standards from FEPA standards, abrasives graded via the FEPA standard have the number preceded by the letter, “P”. So if you buy new wet/dry sandpaper made in the US, you are likely to see “P600” or “P800” grit on the back, not just “600” or “800” grit.

Scotch-Brite nylon pads come in CAMI grades.
Abralon, being made in Europe, uses the FEPA grades. Their numbers are basically 2x what the equivalent US grit level is. For instance, the common Abralon pads are 500 grit FEPA, 1000 grit FEPA, 2000 grit FEPA and 4000 grit FEPA. These are equivalent to 360 grit US, 550 grit US, 1000 grit US and 2000 grit US.

SCOTCHBRITE GRIT CHART (courtesy of Charlest) Current as of 01Nov09

3M Scotch Brite Nylon Pads:
3M Chart
Less Aggressive --------> More Aggressive
7445 7448 6448 7447 6444 7446 7440
Finer Finish --------> Coarser Finish

(The value inside the parentheses is directly from 3M.)
CODE  - COLOR  -  3M Name                      - US GRIT Number
7445 - White pad, called Light Duty Cleansing - (1000) 1200-1500 grit US
7448 - Light Grey, called Ultra Fine Hand - (600-800) 800 grit US
6448 - Green, called Light Duty Hand Pad - (600) 600 grit US
7447 - Maroon pad, called General Purpose Hand - (320-400) 320 grit US
6444 - Brown pad, called Extra Duty Hand - (280-320) 240 grit US
7446 - Dark Grey pad, called Blending Pad (180-220) 150 grit
7440 - Tan pad, called Heavy Duty Hand Pad - (120-150) 100 grit

* There are also Blue Scotch-Brite pads which are considered to be about
  1000 grit.
* Gold Scotch Brite nylon pad, called Clear Blend 07745, 1200 grit
  (and finer).

1. The above pads have in the past come in 6"x9" sized pads.
2. Many of the above abrasives come in 4.75" x 15 ft roll, perforated into
   6" pieces.
3. The white pad, 7445, uses talc as the abrasive. For practical purposes,
   it is very hard to affect the surface of a bowling ball with it. A ball
   is just too hard.

TRIZACT GRIT CHART (Courtesy of Charlest) Current as of 01 Nov 09.

Trizact use the hardest abrasive outside of diamonds.  They last a long time.
Their original purpose was to finish and polish hard substances like Corian and glass.
Trizact pads used to come as only 5" pads with a velcro backing, not foam.
Today, they also come in 6" pads, with a thin foam backing as well as velcro.
3M calls them Trizact™ Hookit™ II Blending Discs.

The original  Trizact only came in 4 colors and 4 grit levels.
They are called 3M Trizact™ Hookit™ II Film DIscs.
Their grit levels were specified in microns (u)).
Green -   A35 ~ 35 micron ~ 360 grit US (~ 500 grit FEPA)
Blue  -   A10 ~ 10 micron ~ 800 grit  US (~1600 grit FEPA)
Orange - A5 ~ 5 micron -~ 1600 grit US (~ 3000 grit FEPA)
White - Cerium oxide - ~ 3000 grit US (~ 6000 - 8000 grit FEPA)

Today, Trizact can be found not only by color but by grit (FEPA) level, with
a foam backing, as stated above. They are generally available in boxes
of 15 in many grades:
P240, P320, P400, P800, P1000, P1200, P1500, P2000, P3000, etc.

3M Super abrasives are micron graded, that is, measuring the average size
of an individual particle on that product.
Standard abrasive grading is based on the screen mesh used to separate
out the particles for a particle grade. In simplest terms,
in a  1"  line of grade 24 product there are ~24 particles.
In a 1" line of grade 600 product there are ~600 particles.
In comparison, 9u=1200 grit, 15u=600, 20u=500, 30u=400, 40u=320



Just thought I would pass this on. I asked Roto-Grip whether they recommended Abralon over Scotch-brite and this is the answer I got:

They work, but not as effectively as abralon. For our official stance on surface alterations I will include a short essay I have written on the subject…

Thank you for contacting us with your concern. As far as ball reaction is concerned, we have several recommendations to maintain ball performance and life, but the primary area of concern is with the surface topography of the ball. As a quick over-view, surface topography in the bowling industry has been measured with specific ‘Ra’ and ‘Rs’ standards. These values directly relate to how aggressive the coverstock is and how much friction the coverstock can generate. The Ra value measures the standard deviations above or below the surface of the ball. For example, a series of high peaks and low valleys would be measured with an extremely high Ra value. Likewise, the Great Plains with a relatively smooth landscape and rolling hills would have a low Ra value. Rs is not as important, but by definition is the average distance between each individual peaks.

The reason these numbers are important is because of the correlation between ball reaction and high Ra and Rs values. Essentially, the greater the Ra and Rs number, the more friction the coverstock can generate. The more friction the coverstock can generate, the greater hook potential the ball will have. What happens when a ball dies is the coverstock has lost the surface deviations originally found on the ball from the out of box finish. These deviations (high Ra and Rs numbers) are created in our finishing and rounding process by creating deep grooves, cuts, and scars on the surface of ball. Later, when the ball is finished, these rough surface deviations are smoothed and ‘polished’ but they are not completely removed. If you were to then examine the coverstock on a micron level, the steep peaks and valleys would still be on the surface of the ball, but they would be rounded. This creates the type of ball motion where the ball will still skid through the heads and midlanes cleanly, but still have a tremendous amount of friction generation capabilities as the ball enters the buff or exits the pattern.

However, as the ball encounters normal use, these peaks slowly flatten and the valleys collapse. If measured after normal use, the once high Ra and Rs numbers would be much lower than the previous out of box finish. Hence, the ball slowly loses ball reaction with each use. Cleaning the surface will help keep the ball reaction consistent and also break down lane oil, but it is not capable of restoring original out of box Ra and Rs values. Luckily, our research has found a fairly simple method to restore the out of box finish.

In order to restore these numbers, abralon pads are recommended for virtually every ball in our current or past production line. The easiest and fastest way to refinish the ball is to use a 360 grit abralon pad on the ball. If the ball is being finished by machine, 60 seconds is usually sufficient whereas other methods may take longer. The whole idea is to thoroughly, cut, scar and groove the surface of the ball with the 360 grit pad. Before finishing the 360 grit, make sure the entire surface of the ball has been evenly cut. If it is done by hand or by a ball spinner, a cross-hatch finish is recommended. For the next stage, very lightly sand the surface with a 500 grit abralon pad. This will lower the Ra and Rs values slightly, but it is not going to completely destroy the surface deviations created from the previous stage.

After the ball has been lightly sanded with 500 grit abralon, please skip directly to the original out of box finish. For example a 4000 grit finish, no polish would require using a 360 grit abralon pad, then light application of a 500 abralon pad finally, skip the 1000 and 2000 stages and go directly to the 4000 finish. The 360 and 500 grit abralon pads will reproduce the original deep grooves and cuts from the factory rounding and finishing process setting the foundation for the final finish. Then, by skipping directly to the 4000 grit abralon stage, the surface will be smoothed and ‘polished’ without destroying the surface deviations. This effectively leaves the surface with the high peaks and deep valleys, but they are not as sharp or jagged. This should restore the original ball reaction allowing the ball to skid on oil, read the lighter buff areas of the pattern and still have amazing recovery potential on the backend.

For polished balls, reproduce the 360 and 500 grit finish and then apply Storm Step 2 Finishing Compound. This is the exact same finishing compound we use on all of our 1500 grit polished balls. The trick to the polish application is to use less polish and very light pressure. Step 2 Finishing Compound has a resurfacing medium in it that sands the ball while it is being polished over-application of the compound will effectively destroy the same surface deviations that originally gave the ball its strong out of box finish.

The key to restoring any finish is deeply cutting the ball with the fresh 360 grit abralon pad and then very lightly applying a 500 grit pad. The same is true of the final step as well. Over-application of the 1000, 2000, or 4000 grit pads can destroy the surface deviations created by the 360 and 500 steps weakening the over-all ball reaction.

Hopefully, if the sanding process has been repeated successfully, the end results will yield a ball with nearly the exact same Ra and Rs values originally found on the out of box finish restoring life back into the ball.


Generally accepted as follows:
1- Coverstock and surface preparation 65-70%
2- Core 15-20%
3- Pin placement and Dynamic weights 10-15%
4- Mass Bias 0-10%
5- Balance hole 0-5%
6- Static Weights 0-2%

This is an coverstock additive that can be either a softer compound that compresses and give the ball a larger contact patch or a harder compound that protrudes from the cover acting as a spike to reach through the oil and grap the lane surface. Particle is added to both solid and pearlized covers. Benefits: the ability to handle more oil, smooth out over reacting backends, and handle more carrydown.

A type of ball surface that has an additive (mica) in the coverstock that stiffens the cover and causes a later reaction for the given coverstock base.
Benefits: good for when the heads are drier, good when you have to get deep due to increased recovery in the backend.

A type of ball reaction on the lanes where the ball begins to hook and then stops its hooking action and turns into more of an end over end roll. This is not the same as "Roll Out".

This is when a ball has lost all of its rotation and tilt and is in a "pure" roll. This not the same as "Hook Out".

The question was posed in a prior BR post. If I have a “Free” armswing will my ball speed change?
The answer yes.
If you do have a completely free armswing you will actually get more speed from the heavier ball given the same backswing height.
If you muscle the ball the lighter ball will be rolled faster.
I know some of you are saying WHAT, I will explain.
Someone in the previous post stated that both balls would fall at the same speed because they have the same surface area so they would have the same wind resistance. True they have the same area but not the same weight and an objects terminal velocity and gravity induced acceleration rate is a combination of mass (weight) and volume (area). The wind resistance becomes irrelevant because neither ball will come close to it’s terminal velocity. Which is the point that acceleration created by gravity stops due to the relation between the objects mass and aerodynamics/volume.
However ball speed should not be a factor when trying to adopt a free/pendulum armswing because speed changes will be barely negligible with the same backswing height. What a bowler should be considering is the fact that a free/pendulum armswing creates consistency, and speed differences will be easier to make by just raising and lowering the ball when at address. You may lose some revs on the ball with this new “Free” swing, but you may also gain some because of the more relaxed hand giving you a cleaner thumb release increasing the time between thumb exit and finger exit giving more time to induce revs.

"Generally" classified as follows:
Dull finish: below 600grit sand paper and green scotch brite
Matte-smooth finish: Between around 800grit and 1200grit sand paper or grey scotch brite
Sheen: finer than 1200grit
Best way find out the actual box finish is to contact the manufacturer.

Ringing 10 (Excess energy)
1. Excess speed.
2. In the oil too long.
3. Excess side rotation.
4. Too much loft.
5. Weaker than normal release/thumb stuck.
6. Ball/condition match-up (late roll).

1. Reduce speed (lower the ball slightly @ address).
2. Move feet 1 board left keeping same target, move feet and target 1 board right.
3. Stay behind ball a bit more (go through not around the ball), change hand position, spread little finger.
4. Reduce loft (soften grip, increase knee bend).
5. Remove tape, don’t “knuckle” the ball.
6. Move back 4-8” on approach or switch to earlier rolling ball (not necessarily stronger), move your target closer to the foul line.

Weak/Flat 10 (Insufficient energy)
1. Insufficient speed.
2. Not in oil long enough.
3. Insufficient side rotation.
4. Ball/condition match-up (early roll).

1. Increase speed (raise ball slightly @ address).
2. Move feet 1 board right keeping same target, move feet and target 1 board left.
3. Change hand position, spread index finger farther, reduce spread/tuck little finger.
4. Move forward 4-8” on approach or switch to later rolling ball (not necessarily weaker), move your target farther from the foul line.

Note: All adjustments are from a right handed point of view. Forward backward adjustments may not work for some, because some increase and decrease their foot speed when making these adjustment and end up the same distance from the foul line which negates the adjustment for earlier/later roll and will actually cause the opposite of the desired result due to speed increase/decrease.

One way that helps to identify which type of 10 you are leaving is to watch the ball path through the pins
\ = ringing, / = flat/weak, | = no 10. Consequently 9-10 splits come from ringing and 8-10 from weak/flat.

ONLINE LINKS  Current as of 01 Nov 09.

BTMs REVIEWS click here






USBC BALL CLEANER LIST - ACCEPTABLE/NON-ACCEPTABLE  Look in Equipment Specs Features window, click on More.






"Well after all the debate about crankers v. strokers, and how seemingly strokers do not give crankers much deference, I would like to indicate how some of us crankers rev the ball and just how much effort it takes to do so. Maybe then you strokers will understand why we are not as accurate.This is not the only way to rev the ball, its just how I do it. A lot of others have different overall styles, however, they will use similar parts in their game to obtain a high revolution rate.
First and foremost, your legs are your foundation. Legs provide you with stability and balance, thus allowing a bowler to utilize and transfer power from the legs to the release point. Proper knee bend is critical, however, it does not mean that you have to "get low." There is a point where if you get too low you will lose your leverage which will result in loss of revs. Everyone has a different point so no two knee bends will be exactly the same. Examples, Ryan Shaffer with his stiff knee pop up style and Robert Smith with his deep knee bend style.
Crankers have a cupped wrist. They may open it up at the backswing, however, before release their wrist is cupped.
Next, crankers open up the shoulders to get more leverage on the ball. Ala Amletto, Robert, Rudy, Couch.
Next, crankers make a slight forward movement of the hips while closing their shoulders. This slight forward movement of the hips and closing of the shoulders adds to the power in the release.
Next, most crankers create a flat spot in their release. This flat spot is right before the ball reaches the side of the body. During this flat spot, some bowlers will bend their elbow to create the flat spot, and other will keep a straight elbow but slide more to create the flat spot.
Typically,the bowlers that plant, grip and rip bend their elbows more and the ones with the straight elbows slide more. A flat spot is necessary for the bowler to get under or around the ball and it also serves as a initiator in getting the ball off the bowlers hand. Again, this flat spot is right before the ball reaches the side of the bowlers body.
A great example of a bowler that uses a highly pronounced flat spot is Chris Barnes. Great form and gets a good amount of turn on the ball. Barnes has a powerful release which is greatly created by the flat spot he incorporates into his style.
Next is the release point. This entails uncocking the wrist and then cocking it back ending with lifting through with the fingers. The whole release point at maximum leverage is end the end of the flat spot (when the ball reaches the side of the body) to the point where the ball reaches the plant foot. From the time it takes the ball to go from the side of a bowlers body to the plant foot, the bowler must release the ball which comprises uncocking the wrist, cocking it back, and then lifting with the fingers. In order to do this properly, a bowler must have a quick wrist. I am not going to get into the trail leg position because its rather obvious where it should be. Well that about wraps up the major components of turning up a ball. Next time you see a cranker (a real one not a wannabe kid), think of all the things that he/she must do to get all those revs. And realize that the cranker created that area on the lane so you should not be jealous of that area. With all this extra effort put into releasing a ball, the payoff is area and the sacrifice is accuracy. Yes we will not be as accurate, but we will have created area to make up for that loss of accuracy. By area I mean lane area as well as pocket area. And of course, with proper dressing of the lanes, our area can be taken away. Strokers will always have a chance so be glad that you have your chance and let us cranker bowl in peace.
In case some of you need an analogy, think of cranking a ball like racking a whip. The handle being the bowlers leg. The handle must be solid and stable. The whip is like the bowlers hand. It must cup, uncock and then cock back to get that snap. Just like a whip how the whip makes its sinusoidal like figure before cracking, the end of the whip being like the bowlers fingers.
Or, how about comparing it to a basketball shot, except that bowling is underhand. Think of how the basketball players wrist is used to put spin on the ball. That is how a cranker uses their wrist to also turn the ball, except that bowlers are underhanded.
With regards to Bowlerbuf, a quick wrist is necessary. That is how small people like Amletto and Hoskins can rev up the ball. They do not have the physical strength like you, but they can turn up a ball more than 99% of bowlers out there due to their quick wrist. Another example is Michelle Feldman. I bet she can turn up the ball more than 99% of people here men included. Yet I bet her hand is much smaller in span. I believe it’s in the upper 3" something range. She is an example of a bowler with a quick wrist.
Bowlerbuf, you said that you have to back off the thumb for more revs, you need to do this because you do not have a quick wrist. Backing off the thumb allows a bowler to get the ball of their hand quicker which is necessary for more revs. However, someone with a quick wrist does not need to back off the thumb in order to get the ball to fly off their hand.
With proper technique, a bowler can rev up a ball. Yes some power is necessary, however, proper technique is essential to cranking it up.
In conclusion, for a high revolution rate, a cranker opens the shoulders, plants (some with minimal slide), closes the shoulders, moves hips forward, creates a flat spot in their armswing, uncocks the wrist, cocks it back and lifts through with the fingers."


This is a condensed version of Lucky Lefty’s post.

The perfect full span grip is defined so well by Bill Taylor in his book "Fitting and Drilling a bowling ball". In it he describes methods to determine the perfect span(middle of last and next to last joint to lip of finger insert or hole), perfect thumb pitches(forward/reverse are based on span), lateral thumb pitches(based on the coke bottle test)and differences in span lengths for middle and ring finger(based on laying hand on ball and observing difference in lengths).
His method usually ends up giving a satisfactory result for supplying ideal elements of hold, lift and turn for most common bowling situations. Note most people end up following his method with some reverse thumb pitch(if span over 4 1/4 inches), some lateral under palm pitch(if right handed right pitch) (if left handed then left pitch) this element ends up supplying turn while the bowler throws with a straightish elbow position and straight or cupped wrist.

Lateral thumb pitch
Many bowlers are starting to go to lateral out and forward pitches of the thumb when their anatomy (as called for by the Bill Taylor tests) call for reverse pitches(due to span) and lateral under palm pitches as determined by coke bottle test. So it is with the coke bottle test. Where ones thumb points is unique and different for most but let us say over 90% of cases the thumb does not end up pointing to the index finger(lateral out). Also most bowlers are not guilty of hooking it or turning it too much!
If the bowler has insufficient lateral under he subconsciously feels that he can not get the ball back enough if he swings his arm out away from his ultimate target(the pocket) and so therefore he chicken wings or pulls his armswing.
The proper lateral pitch (for his and your anatomy) instead allows the arm to pursue the intended starting line of the ball and feel that the ball can come back. (Naturally another fault that will cause this lack of trust is not having the feet in the right place for the shot).

Now let us talk about the proper span.
One of the things Bill Taylor says that I believe is one of the most important things said in the book is that the ultimate test of the proper full span he recommends is That during the backswing that the pressure of the ball should be near the joint of the last pad of the finger and on the downswing the pressure should then cover the complete pad!

Finger pressure in the backswing should be. Near 1/3 of pad close to jointline.
Legend X = pressure, . = no pressure

Joint line
Finger pressure on the downswing
Joint line

Get it!?
The too short span leads to pressure on the whole finger pad on the backswing and pressure ONLY on the fingertips on the downswing.
This is the final dialing in process on finding span length in the Bill Taylor method! I have found this is easy to do with shims!!! Spans can be lengthened over a 1/16 th this way if one uses finger inserts.

Most peoples middle finger span is shorter than the ring finger!
Even though the middle finger is longer. The break even point is when the middle finger is 5/16” longer than the ring finger according to Bill Taylor.

Modern lane conditions and today’s drilling variations
So why are SOME bowlers today going to Shorter spans than the Bill Taylor method, reverse pitch in the fingers, lateral out pitches for the thumb(even though the hand coke bottles for 1/8 lateral Under palm), and dramatic forward in the thumb.
Far different than the tables.
Great questions. For those who have never bowled on these tricky patterns put out the PBA I will venture in to this, for our masters of the universe please bear with me!
The times I have bowled in PBA ProAms (one ladies, one mens supposedly the shot for the tournament) has left me with this general impression.
The patterns are made to embarrass the area bowler.
Characteristics are good amounts of head oil, OB to the outside of the lanes, very little hold area, a two or 3 board break area that will hit the pocket at 45 feet.
The result being that balls delivered with a ton of side turn, finger lift, and lots of retained energy at the break point LEAP of the Non buffered transition area and pursue all sorts of ending positions to the pins(not necessarily the pocket.)
How do I know? First time I came in after bowling about a 700 with my friends in some fun dollar matches and used the same leverage drilled equipment and shot about 450 in my home house(the one I bowled about 700 the night before. Next time out I brought some duller weight hole on PAP mild stuff and shot about 660 scratch. Same bowler similar execution!!!
What is going on in the pattern is the explosive move off the breakpoint from the buffed house shot with a crown. The power, turn, lift, and side roll created by the Bill Taylor drilling is TOO much for some. Such Esteemed posters as Kimbo has stated that with the new conditions she felt she had to change her side roll from 60 degrees to 40 to 45 for the new conditions.
So what happens.
To reduce side roll many



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Re: Unofficial FAQ Section (repost)
« Reply #106 on: March 21, 2012, 03:21:16 PM »
Doesn't show up even though it is supposed to be a Sticky unless it is ttt'd every once in awhile.


Need bowling information? - Please check this:  BR FAQ
Half a century of bowling and still learning.

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           Lifetime membership since 2013.


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Re: Unofficial FAQ Section (repost)
« Reply #107 on: September 16, 2012, 02:48:41 PM »
thanks for the post. Has anyone noticed bowling information  has more details then a lot of college classes lol .
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Re: Unofficial FAQ Section (repost)
« Reply #108 on: July 01, 2013, 11:56:48 AM »
Thanks alot!


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Re: Unofficial FAQ Section (repost)
« Reply #109 on: January 10, 2014, 06:14:34 PM »
I'm in