Phantasy Star Online
In Phantasy Star Online, Grinding is a method to improve weapons; most weapons are capable of being Grinded. Grinding a weapon provides it with a bonus: each point of grind gives a weapon an additional +2 ATP. All weapons have limits on how much they can be ground, and some weapons cannot be ground at all.
Phantasy Star Universe
In Phantasy Star Universe, Grinding can be used to improve your weapons, usually in the form of an ATP/TP boost and/or a PP boost.
To Grind a weapon, the player must possess a Grinder of equal to or higher rank of the target weapon; for example, an A Rank weapon will only accept a Grinder of A Rank or S Rank. Once you are ready to grind, you must unequip the weapon and take it to the proper Grinding Shop. Certain weapons are only accepted at specific Shops.
Weapons have a base maximum Grind of +10. As your Grind Level increases, the success rate of Grinding to the next Grind Level decreases. If you fail a Grind, the weapon's Grind Level will reset, and its maximum Grind Level will be permanently reduced by -1. A weapon with 0/0 Max Grind cannot be Grinded.
It is possible to raise the chance of succeeding at Grinding, including having a good Photon Fortune and using a higher quality Grinder.
Phantasy Star Online 2
In Phantasy Star Online 2, grinding can now be used to improve all forms of Equipment, including Weapons, Units, and Skill Rings. The original system has been hyper-simplified compared to previous installments. There is also a second type of Grinding known as New Type.
To Grind equipment, the player must be in possession of Grinders. Once you are ready to grind, the equipment in question must be taken to the Item Lab in the Shop Area.
Weapons and Units have a maximum Grind Level of +10. Depending on the rarity of the target gear, more Grinders may be required for a Grind attempt.
As the Grind Level increases, the chance of succeeding at a Grind decreases based on Grind Level and the target item's Rarity. Failing at a Grind will render the spent Grinders and Meseta wasted. If there is a Risk involved, there is another possibility that the item's Grind Level will be reduced by a certain number of Levels, undoing your progress.
Any equipment of Rarity 13 requires Lambda Grinders in place of regular Grinders, which are significantly more rare and can only be obtained in a few select ways.
Skill Rings can also be grinded like Weapons and Units, but require additional materials in addition to the required Grinders. The higher the Grind Level, the more materials will be required to perform a Grind. Skill Rings can be upgraded to +20, with the primary effect of the Ring improving per Grind Level. Left Skill Rings can additionally gain a +1 to a chosen stat per Grind Level. Skill Rings always have a base 80% chance to succeed at Grinding.
Certain Candies can be grinded by investing Grinders and a large sum of Meseta. Grinded Candies have their size reduced, allowing you to fit more into a single Candy Box. The max Grind of a Candy can either be +1 or +2. Candies always have a base 80% chance to succeed at Grinding.
It is possible to augment Grinds with special items, such as Risk Up (+1), Grind Success (+5%), or Grind Skip (->+7).
New Type is a Grind method introduced in EPISODE 4. Weapons with the "-NT" suffix and most weapons released after their introduction are eligible for New Type grinding. New Type weapons are considered separate weapons from their original counterparts.
To Grind a New Type weapon, the player must be in possession of expendable Weapons and Grinders. Once you are ready to Grind, the weapon must be taken to the Item Lab in the Shop Area.
New Type weapons require both other Weapons and Grinders to increase its Grind Level. The required number of Grinders is equivalent to the number of Weapons sacrificed in Grinding. The Weapons spent translate into EXP for the New Type weapon; when this value reaches 100%, the New Type weapon increases in Level by +1, granting a 1% addition to its ATK stat. The higher the Grind Level, the more EXP is needed to reach the next Grind Level.
In addition to the fact that New Type grinding cannot fail, it is possible to achieve a Great Success upon Grinding. This doubles the EXP added to the Weapon in that current grind. It is possible to raise the odds of this happening with certain items.
New Type weapons have a max Grind of +30. However, they can be upgraded to +35 by using another copy of the target Weapon in Grinding. This is known as an Overgrind.
At every 10 Grind Levels, the player will be required to unlock the Weapon's Potential to continue Grinding. This is done in the same way Potential Unlock is done with normal weapons, but is performed in the Grind Weapon menu.
Element Value can also be increased through New Type grinding, following the same rules as normal Attribute Grinding. However, instead of using Synthesizers, the weapon used for Attribute Grinding is simply added to the New Type grind pool.