Thumb Screws 1.Knurled head Thumb Screw 2.Steel,brass,Al thrumb screw 3.Size: ... samples for thumb screw Thumb Screws 1. Head type of thumb screw:KINDS OF HEAD,KNURLED2. Drive of thumb screw:Torx/6 ... #4-#107. Surface of thumb screw:Plain, black finished, Zinc plated (Galv), Nickel, phosphate black, 3Cr zinc,Passivation8. Packing :General packing ...