Hammer Overview

The Hammer (ハンマー Hanmā) weapon class is a fairly common weapon type able to be used by players since the first Monster Hunter game. Staunch and resilient, the hammer is perhaps the first representative weapon-of-choice to dictate pure, unadulterated damage directly to the target. In this field, the weapon's typical attributes allow a hunter to run openly with the weapon drawn, perform short-range, almost "bunting" and swing attacks with their initial attack buttons, and the ability to charge up different types of swings while moving. As the hammer class has immense damage potential, and indeed, some of the outright highest raw damage in the game, the weapon boasts no defensive or evasive capabilities aside from the standard rolling dodge maneuver. A sense of timing is needed to master the weapon's true damaging traits: releasing charged swings while timing and aiming diligently against the foe's movements. No easy task. Further, hammers have a decent variance of elemental attributes, and are useful for racking up elemental damage. It's not possible to cut tails with a hammer, but it is easy to break heads and other body parts. 


Typically of moderate sharpness, the hammer is able to supplant high damage through its shoulder-button charged moves. These include a single swift swing, a one-two "golf swing," and, depending on if the hunter is moving or not, a whirling attack or a heavy bash onto the ground.
Stun damage to a large monster can be visually noted when yellow streaks or "stars" are seen to appear at its head. The Monster will fall down and have stars circling its head when it receives enough stun damage and is "Knocked Out". This is the perfect time to launch a few combos while the monster is vulnerable.


Hammers are sheer brute force. The best defense here is a good offense, and the best strategy for a hammer is to line oneself up safely while timing the R button swings at vital points. When hunting in groups, the hammer is useful to knock out monsters or make them flinch, while other hunters with cutting weapons are given a great opportunity to cut off the tails of monsters, and break parts without worrying about the monster attacking them. When you use the swinger at 4 swings press triangle to perform the most effective hammer damage. Players call that powerful swing the "Golf Swing" This can KO a monster. As of MH3, landing attacks on any part other than the head will drain a monster's stamina, which will slow down their movements and disable some of their more dangerous attacks. 

- Weapon Traits :

It is very often to see newer players dismiss the hammer for being heavy and slow to use despite its ridiculous amount of raw damage. A fact with the hammer is that due to its high damage, you will not be landing many hits during a hunt compared to other weapons, but still dealing a lot of damage. If you're used to dealing 3-4-5 hits and then retreating, you will find the hammer awkward. The following tips are written with accordance to MH3. 

• Use the Superpound (Full Charge attack, No direction applied) over the Spinning Attack (Full charge, Direction applied). The Spinning attack does okay damage, provided every swing hits. The biggest issue with the spinning attack is that you are caught in the animation until the spinning stops, if you do find yourself in this situation and either need or want to get out of the way. Pressing the Groundsmash (Triangle or X) will get you out of this after 2 spins. From there you are free to roll away or continue with a Groundsmash combo. Though keep in mind the charged spinning attack isn't all that bad. On the chance of actually hitting with a status effect, the spinning attack will hit numerous times, this is particularly good in a few situations. e.g. a monster is limping away, a paralyze hammer paired with the spinning attack gives you the chance to paralyze the monster while dealing a moderate amount of damage.

• The Superpound attack will be your main damage dealer, the Golfswing combo ( Triangle, Triangle, Triangle/X, X, X) does deal more damage, however you are not given the luxury of the monster sitting there to take it. Plus chaining Superpounds will do more damage in a certain amount of time than chained Golfswing combos. The beauty of the superpound is that you can run in, release the charge, roll out and you're safe while dealing a large amount of damage. This does take practice to perfect due to the fact the difference between the superpound and the spinning attack is whether you're applying movement direction.

• If you do get the chance to commit to a golfswing combo, you can use an upward swing (just tap the R button or charge) to chain another golfswing in. This saves time compared to performing the combo, rolling away, finding the spot on the monster and the starting the combo again. In using the upward swing you are also getting another hit in as well.

• Timing, as with the Greatsword, is fairly crucial with the hammer. Keeping the charge in preparation for a superpound does decrease your stamina, with certain monsters this does keep you at a disadvantage - say you need to roll out after the superpound, insufficient stamina could mean taking damage. If you are still unfamiliar with the monster you are hunting, it is good idea to pack (Mega) Dash Juices. Dash Juice in particular is easily made with common materials.

• Hammer is a very straightforward weapon, apart from its raw damage it doesn't have many mechanics like the Longsword or Greatsword with skills. This gives you the freedom to gem armor sets with things like Elem/Attack up or Constitution. Don't be afraid to gem for basic things.
• When Knocking Out a monster, it is not wise to go for as many 3-hit combos as possible. Instead, perform the first two hits, roll away, and then use the 3-hit combo. The reason being is that after performing the final golfswing, you have lots of recovery that cannot be rolled out of. On the other hand, the first two hits of your Triangle combo can be rolled out of almost immediately. In doing this, you ensure the most hits on a monster without taking any chances. By the time you finish the golfswing on your second combo, the monster should be getting back up, where, depending on the monster, you can probably throw in a quick tap of the R button and then roll away.
• The charge can be cancelled with a roll, so you can be very liberal in using it. It's a good idea to start a charge when you see that there may be an opening. If there is, rush in and take it, taking advantage of the charge you built while waiting. If not, roll away to cancel the charge. Just take note that enough stamina is needed to roll as usual, so don't hold the charge for excessive amounts of time.
• The Focus skill is good for a hammer, but it is not as helpful as it is for other weapons. This is because the hammer's attacks differ on the length of the charge, and using the Superpound is not always preferable as it leaves you open with a very long recovery.

- Pros and Cons :

Advantages

• Surprisingly light when unsheathed.
• Highest raw damage out of all blademaster weapons
• Particularly useful charged attacks. (Can also remain mobile while charging attacks)
• Can KO monsters
• Drains monsters' stamina (in MH3 and on)
• Short range and uniform attacks gives it great precision when targeting monster weak points

Disadvantages

• Slow to attack
• Requires good timing
• Sharpness is pitiful(but not consumed as fast, due to fewer attacks)
• Charge attacks cost stamina
• Elemental and status damage is mostly poorer than other weapon types
• Unable to cut tails
• Tendency to launch allied hunters into the air with the drawing attack / golf swing
• Unimpressive reach — must be closer to the monster than other weapons, making evasion significantly more difficult

- Tutorial for Beginner Hunter (by GaijinHunter / @aevanko)
https://www.youtube.com/watch?v=EQD-adUNd10