28 x 4 1 2 July 8, 2019 16 32 64 128 1 4 28 x 1 2 screw 1 4 28 x 1 2 bolt 28 2 x 11 7 x 4 1 cm 1 2 4 x 28 33 O ring 28 4 x 1 25 4 x 1 )- 20 28 1 4 28 x 1 2 set screw 4 x 1 )= 2x 28 4 x 1 2 28 40 1 4 28 x 1 2 machine screw 1 4 28 x 2.5 grade 5 bolt 1 4 28 x 3 1 2 bolt 1 4 28 x 2.5 1 4 28 x 2.5 bolt 1 4 28 x 3 1 2