Percussion instrument, bottom frame reinforcement method and percussion instrument manufacturing method

A bottom frame reinforcement method, which is a bottom frame reinforcement method in a percussion instrument, the percussion instrument comprising:

• a head, forming a percussion surface;
• a housing, having a body part in a cylindrical shape having an opening on an upper end side covered by the head;
• and a bottom frame, forming a bottom surface of the housing,
• wherein the bottom frame comprises:
• a central part, forming a central portion of the bottom frame;
• a plurality of radial parts, radially extending from the central part toward an outer edge side of the housing;
• and an outer peripheral part, connecting outer edges of the radial parts in a peripheral direction, the bottom frame reinforcement method comprising:
• forming a concave part extending from a side of the central part toward a side of the outer peripheral part protrusion on a lower surface of each of the plurality of radial parts, and
• forming a pair of protrusions of each of the plurality of radial parts respectively extend downward from two opposite sides of the concave part in the peripheral direction and extending from the side of the central part toward the side of the outer peripheral part, and a plate of each of the pair of protrusions forms a bottom surface of each of the plurality of radial parts.