1.Ensure materials are authentic 2.Strict production process and testing process 3. long lasting,fasting drilling

1.    meterial:  HSS M2

2.    thermal treatment:  bit part 62-65HRC

                                           bit shank 40-50HRC

3.   surface treatmen:   TI coated

 (The surface of the drill bit without tipping blunt crack significant bump and grinding burn and influence the use performance defect,Product no surface rupture, burr, rust, black spots or other undesirable phenomenon)

4.   shank :  hex shank, (CNC milling machine control, handle uniformity division.)

5.   flute type: straight flute

min-max	description	overl length	shank	max thickness	steps
1/4''-1-3/8''	1/4"-3/8"-1/2"-5/8"-3/4"-7/8"-1"-1-1/8"-1-1/4"-1-3/8"	3.3inch	0.3inch	5mm	10
7/16 ''-1-1/8"	7/16-"1/2"-9/16"-5/8"-11/16"-3/4"-13/16"-7/8"-15/16"-1"-1-1/16"-1-1/8"	3.5inch	0.3inch	5mm	12
3/16"-7/8"	3/16"-1/4"-5/16"-3/8"-7/16"-1/2"-9/16"-5/8"-11/16"-3/4"-13/16"-7/8"	3.2inch	0.3inch	5mm	12

Inch Size HSS step drills