Hejian Zhongcheng Drill Bit Manufacturing Co.Ltd. was established in 1997 ,specializes in designing ,manufacturing ,marketing and serving tricone bits(steel tooth& TCI insert),PDC bits (matrix& steel body) and drilling tools in petroleum industry . It is a privately owned and proudly company and we have grown to become a leading manufacturer of high quality drilling tools as well as finding custom solutions to complex problems. Our goal is to provide our customers with the best quality drilling tools, accessories and service .We are supported by many years of experience and trained professionals.

 

Brand named:SRF,it maintains a strong reputation in the oil & gas industries , water well ,construction, exploration, geothermal, mining, and as a company that can provide dependability and high quality products at excellent value.Size ranging from 2 7/8 inch to 26 inch.

You can trust us to meet your industry's demands. From working with drilling tool designers, custom part design, drafting, implementation to machining fabrication, assembly and distribution, we are ready to meet any of your industry's drilling challenges. We feel it is important to work closely with both our customers and suppliers to develop a relationship based on trust and cooperation. Our customers from United State,Canada,Australia,the Middle East,Brazil ,Mexcio,South Africa and etc. Please don't hesitate to send your inquiries to us 

BIT SIZE		API regular pin	Recommended make up torque
Inch	mm	Inch	KN.M
3 3/4	95.3mm	2 3/8	4.1~4.7
3 7/8	98.4 mm	2 3/8	4.1~4.7
4 1/8	104.8 mm	2 3/8	4.1~4.7
4 1/4	108.0 mm	2 3/8	4.1~4.7
4 1/2	114.3 mm	2 3/8	4.1~4.7
4 5/8	117.5 mm	2 7/8	6.1~7.5
4 3/4	120.7 mm	2 7/8	6.1~7.5
4 7/8	123.8 mm	2 7/8	6.1~7.5
5 1/2	139.7 mm	3 1/2	9.5~12.2
5 5/8	142.9 mm	3 1/2	9.5~12.2
5 2/3	143.9 mm	3 1/2	9.5~12.2
5 3/4	146.1 mm	3 1/2	9.5~12.2
5 7/8	149.2 mm	3 1/2	9.5~12.2
6	152.4 mm	3 1/2	9.5~12.2
6 1/8	155.6 mm	3 1/2	9.5~12.2
6 1/4	158.8 mm	3 1/2	9.5~12.2
6 1/2	165.1 mm	3 1/2	9.5~12.2
6 5/8	168.3 mm	3 1/2	9.5~12.2
6 3/4	171.5 mm	3 1/2	9.5~12.2
7 1/2	190.5 mm	4 1/2	16.3~21.7
7 5/8	193.7 mm	4 1/2	16.3~21.7
7 7/8	200 mm	4 1/2	16.3~21.7
8 3/8	212.7 mm	4 1/2	16.3~21.7
8 1/2	215.9 mm	4 1/2	16.3~21.7
8 5/8	219.1 mm	4 1/2	16.3~21.7
8 3/4	222.3 mm	4 1/2	16.3~21.7
9 1/2	241.3 mm	6 5/8	38~43.4
9 5/8	244.5 mm	6 5/8	38~43.4
9 7/8	250.8 mm	6 5/8	38~43.4
10 1/2	266.7 mm	6 5/8	38~43.4
10 5/8	269.9 mm	6 5/8	38~43.4
11	279.4 mm	6 5/8	38~43.4
11 5/8	295.3 mm	6 5/8	38~43.4
12	304.8 mm	6 5/8	38~43.4
12 1//4	311.2 mm	6 5/8	38~43.4
12 5/16	312.7 mm	6 5/8	38~43.4
12 3/8	314.3 mm	6 5/8	38~43.4
12 7/16	315.9 mm	6 5/8	38~43.4
12 5/8	320.7 mm	6 5/8	38~43.4
13 1/8	333.4 mm	6 5/8	38~43.4
13 1/2	342.9 mm	6 5/8	38~43.4
13 5/8	346.1 mm	6 5/8	38~43.4
13 3/4	349.3 mm	6 5/8	38~43.4
14 1/2	368.3 mm	7 5/8	46.1~54.2
14 3/4	374.7 mm	7 5/8	46.1~54.2
15 1/2	393.7 mm	7 5/8	46.1~54.2
16	406.4 mm	7 5/8	46.1~54.2
17 1/2	444.5 mm	7 5/8	46.1~54.2
18 7/8	479.4 mm	7 5/8	46.1~54.2
20	508.0 mm	7 5/8	46.1~54.2
22	558.8 mm	7 5/8	46.1~54.2
24	609.6 mm	7 5/8	46.1~54.2
26	660.4 mm	7 5/8	46.1~54.2