SIDE SILL OF UPRIGHT PIANO

PROBLEM TO BE SOLVED: To provide a side sill of an upright piano which may be easily produced at a low cost without using a foaming agent. SOLUTION: This side sill has a plastic skin material 2 which is formed of a top wall 5, both side walls 6, 6 and a front wall 7 connected to each other to a hollow shape and is opened on the bottom side and the rear side respectively by a bottom side opening 8 and a rear side opening 9, an insert material 3 which has a rectangular shape in the cross-section, is inserted into the skin material 2, is fixed at its front surface to the inside surface of the top wall 5 of the skin material 2 and has the rear part projecting from the rear side opening 9 of the skin material 2 and a plate material 4 which is fixed to the lower surface of the insert material 3 and fits into the bottom side opening 8 of the skin material 2.