Center post side stringer spiral curved staircase with metal railing

Center post side stringer spiral curved staircase with metal railing
Description
Center post side stringer spiral curved staircase with metal railing

Specification: 
Center post 300*12mm in carbon steel
Stringer 300*12mm in carbon steel
Stair tread 80mm thickness solid wood tread
Tread support 6mm thickness tread support in carbon steel
Railing # height 36''/42''/1000mm
Baluster 50mm in sus304
Solid Rod 8 layers, 8mm solid rod in sus304
Top handrail 50mm in sus304

Solid wood stair tread options:


Color for the stairs tread can be customized.
Below are some regular color for reference and choose: