Deep hole gundrills

Resolving tool troubles through perfect tool engineering

Customised gundrills

Outer diameter range ø1.6 - 60 mm

Single flute, Double flute, Solid and step gundrills

PCD gundrills, Gunreamers

Amazing facts!

── Introducing ideas and technologies ──

Chungjin Engineering Co., Ltd. from South Korea is a professionally manufacturer of Gundrills and Gunreamers for 20 years since its establishment in 1993. Based on the technical skills accumulated in cutting tool manufacturing over the years, Chungjin have successfully developed their own technology to produce excellent products by incorporating them into the gundrill developed for processing holes in gun barrels with the aim of developing localisation.

Chungjin supplies tools to the domestic and overseas markets with the best quality and technology, and after starting exports, currently exporting to major markets such as Japan, China, and other Asian countries. Through endless product development and efforts, Chungjin obtained a certificate for their R&D department in 2012 to further devote themselves to product research and development, and as a result, succeeded in manufacturing the first PCD gundrill in South Korea and received the Vision Enterprise Certificate Award of the year.

Chungjin can customise gundrills from a minimum outer diameter of ø1.9 to a maximum outer diameter of ø60, and manufacture double flute, step gundrills, gun reamers, gundrill guide bushes, rest bushes, rubber bushes, brass bushes, etc. along with gundrills. In addition, Chungjin solves problems through tool engineering when tool troubles occur.

All employees of Chungjin Machinery are promised to do their best to create the best service for customers, implement the best quality in the industry, and manage customer-centred company in accordance with the company’s management policy.

Specification

Single flute gundrills with brazed tungsten carbide tip

Sizes

DRILL Outside Diameter (ØD 0.005) [mm]	Carbide tip length (ℓ) [mm]	Total length (L)
1.9~3.0 Less	15	As per order request
3.1~5.0 Less	20
5.0~7.1 Less	25
7.0~10.0 Less	30
10.1~13.5 Less	35
13.6~16.5 Less	40
16.6~21 Less	45
21.1~25 Less	50
25.1~30 Less	55
30.1~60	60

DRIVER SIZE based on DRILL Outside Diameter (ØD) [mm]	DRIVER Outside Diameter (ØD) [mm]	DRIVER Inside Diameter (Ød) [mm]
6.0 Less	12.70	4.0
6.1~12 Less	19.05	5.0
12.1~20 Less	25.40	6.5
20.1~25 Less	31.75	8.0
25.1 and over	38.10	10.0

Tip shape

Tip shape	Outer Cutting Angle (α °)	Inner Cutting Angle (ß °)	Work material
Standard type	42	20	Low carbon steel, Aluminum alloy
Standard type	30	20	Carbon steel, Alloy steel

Tip name

DRILL diameter (ØD) [mm]	Oil Clearance (G) [mm]
3.5	0.7
7	1.1
9.5	1.3
13	1.6
16	1.8
19.0	2.4
22.0	2.6
25	2.7

Cutting condition

Work material	Ø2~6.5 mm		Ø6.5~13 mm		Ø13~19 mm		Ø19~25 mm		Ø25- mm
Work material	Cutting speed [m/min]	Feed rate [mm/rev]	Cutting speed [m/min]	Feed rate [mm/rev]	Cutting speed [m/min]	Feed rate [mm/rev]	Cutting speed [m/min]	Feed rate [mm/rev]	Cutting speed (m/min)	Feed rate (mm/rev)
Carbon steel (Less than HB200)	60~70	0.010 ~0.005	70~80	0.020 ~0.030	80~90	0.025 ~0.035	80~90	0.030 ~0.040	80~90	0.035 ~0.045
Carbon steel (Over HB200)	50~60	0.007 ~0.012	60~70	0.015 ~0.025	70~80	0.020 ~0.030	70~80	0.025 ~0.035	70~80	0.030 ~0.040
Alloy steel (Less than HB200)	60~70	0.010 ~0.005	70~80	0.020 ~0.030	80~90	0.025 ~0.035	80~90	0.030 ~0.040	80~90	0.035 ~0.045
Alloy steel (Over HB200)	50~60	0.017 ~0.012	60~70	0.015 ~0.025	70~80	0.020 ~0.030	70~80	0.025 ~0.035	70~80	0.030 ~0.040
Normal cast iron	65~75	0.020 ~0.040	70~80	0.030 ~0.060	80~90	0.050 ~0.080	80~90	0.060 ~0.120	80~90	0.080 ~0.150
Ductile Cast iron	45~55	0.010 ~0.020	50~60	0.020 ~0.030	55~65	0.030 ~0.050	60~70	0.040 ~0.060	60~70	0.045 ~0.080
Aluminium alloy	100~150	0.020 ~0.040	100~160	0.030 ~0.060	140~180	0.050 ~0.080	140~180	0.060 ~0.120	140~180	0.080 ~0.150
Copper alloy	100~120	0.020 ~0.040	100~120	0.030 ~0.060	120~150	0.050 ~0.080	120~150	0.060 ~0.120	120~150	0.080 ~0.150

Cutting quality

Work material	Roughness of finished surface	Diameter expansion amount
Steel (less than HB200)
Steel (over HB200)
Normal cast iron
Aluminium alloy

Gallery

Double flute gundrills with brazed tungsten carbide tip

Sizes

DRILL diameter (ØD) [mm]	Tip length (ℓ) [mm]	Total length (L) [mm]
6.0~7.5 Less	15	As per order request
7.6~9.5 Less	20
9.6~12 Less	25
12.1~18 Less	33
18.1~22 Less	40
22.1~25 Less	45
25.1~	50

DRIVER SIZE based on DRILL Outside Diameter (ØD) [mm]	DRIVER Outside Diameter (Ød) [mm]	DRIVER Inside Diameter (ØD1) [mm]
6.0~12.0 Less	19.5	5.0
12.0~20.0 Less	25.40	6.5
20.0~25.0 Less	31.75	8.5
25.0~30.0 Less	38.10	8.5

※ The above table may be applied differently depending on the characteristics of the processed work material.

Cutting conditions

Work material	Ø6~8 mm		Ø8~13 mm		Ø13~19 mm		Ø19~25 mm		Ø25~ mm
Work material	Cutting speed [m/min]	Feed rate [mm/rev]	Cutting speed [m/min]	Feed rate [mm/rev]	Cutting speed [m/min]	Feed rate [mm/rev]	Cutting speed [m/min]	Feed rate [mm/rev]	Cutting speed [m/min]	Feed rate [mm/rev]
Normal cast iron	55~75	0.050 ~0.100	60~80	0.060 ~0.120	70~90	0.080 ~0.160	70~90	0.120 ~0.180	80~100	0.150 ~0.250
Ductile cast iron	45~60	0.040 ~0.060	55~70	0.060 ~0.080	60~80	0.060 ~0.100	60~80	0.080 ~0.180	65~85	0.100 ~0.180
Aluminium alloy	100~150	0.050 ~0.100	120~160	0.080 ~0.160	150~180	0.080 ~0.160	150~180	0.120 ~0.200	150~180	0.150 ~0.250

Cutting quality

Work material	Roughness of finished surface	Diameter expansion amount
Normal cast iron
Ductile cast iron
Aluminium alloy

Gallery

Single flute gundrills with brazed tungsten carbide tip and chipbreaker

Sizes

DRILL Outside Diameter [mm]	Bit length (ℓ) [mm]	Total length (L) [mm]
6.0~7.0 Less	25	As per order request
7.1~10.0 Less	30
10.1~13.5 Less	35
13.6~16.5 Less	40
16.6~21 Less	45
21.1~25 Less	50
25.1~30 Less	55

DRIVER SIZE based on DRILL Outside Diameter (ØD) [mm]	DRIVER Outside Diameter (ØD) [mm]	DRIVER Inside Diameter (Ød) [mm]
6.0~12 Less	19.05	5.0
12.1~20 Less	25.40	6.5
20.1~25 Less	31.75	8.0
25.1 Over	38.10	10.0