101Leafy researched the games.
Hard Bone Hammer

Hammer made from superior quality bone. Boorish, it proves its material's power.
| Class | Hammer |
|---|---|
| Rarity | 6 |
| Attack | 1040 |
| Slots | 0 |
| Price | 25,000z |
Upgrades
| Upgraded from | Kut-Ku Pick |
|---|---|
| Upgrades into | Hard Bone Hammer+, Lobster Hammer |
Can also be made new at the smithy.
Upgrade tree from モンスターハンターポータブル 2nd G 公式ガイドブック (Enterbrain, 2008), page 722.
Materials
Stout Bone ×5, Giant Bone ×20, Sm Monster Bone ×60, Iron Ore ×15
Plus Class Tcket ×1, Stout Bone ×1