... ,ECC,ESF,ESSF,ESD,ESSD,EY,EYY DingRun High Quality Drill Bits1)Business Type: Manufacture and sale2)Min. Order: 2000 pieces3)Type:X ... 0.5mm to 18mm, of the precision ±0.03mm, and of inner surface roughness Ra0.4-0.6. The types of steel tubes include 10 ... #, 20#, 35#, 45#, 160Mn, 20GrMo, 35GrMo, 40Gr. The products have the characteristics of small-sized ...