Product Overview:
The Symmetric/Concentric drilling system is designed to drill and case a hole simultaneously through unstable ground conditions. The driver bit incorporated with a satisficial ring or reusable ring makes a full face head design which significantly improves the penetration rate and hole straightness of drilling. The internal flushing grooves together with the built-in casing shoes gives a good seal to the button of the drilling hole, and thus minimizing the disruption of the surrounding of the drill hole. 

Application Range: It is suitable for drilling water wells , geothermal wells , short miscopies ,medium mini-type grouting hole of building , dam and harbor project . 
1. Ring bit and casing shoe assembly is welded to casing prior to drilling. Lock the assembly into pilot bit with hammer. The pilot bit's upper shoulder engages the shoulder of the casing shoe. 
2. Hammer's percussive energy is transferred through the pilot and ring bits, crushing rock . Part of impact energy advances casing. 
3. On completion of drilling and casing , the drill string with pilot bit is retrieved by a slight reverse rotation to unlock the bayonet coupling . The ring bit stays in the hole , and can be recovered only if the casing is retrieved 
4. Drilling continues to the desired depth in the bedrock using a conventional drilling.
Our mini excavator owns beautiful appearance, high configuration, superior performance,
low fuel consumption, wide operating range. It is suitable for loosing soil of vegetable green house, campus greening of municipal departments, digging the hole for tree planting of Fruit-land Nurseries, concrete pavement crushing, sand-gravel material mixing, construction work on the narrow place and so on. Use the quick hitch can add the attachment tools like auger, hydraulic hammer, loading bucket, gripper and so on. It can reduce maintenance and operating costs. Liberate the workforce, improve the mechanization, low investment, high return.      

PRODUCT SPECIFICATIONS

model	casing tube O.D./mm	bit diameter/mm	casing shoe I.D./mm	maximum reaming O.D. /mm	hammer style
146	146	123.5	116	156	4"
168	168	146	140	184	5"
178	178	157	150	194	5"
183	183	160	152	198	5"
194	194	178	164	208	6"
219	219	203	192	234	6-7"
245	245	217	205	260	6-8"
273	273	246	233	291	8"
325	325	297	282	340	8-10"
377	377	351	332	405	10-12"

Detailed Images:
Application:
Company Profile
Shandong Hengwang Group Co., Ltd. is a professional company engaged in research , development, production, sales, application and service of rock drill machines ,drilling tools,and pile driver machines.

FAQ

1. Q: Are you factory or trader?

A: We are factory, has passed ISO, contact me showing you the factory;

2. Q: What kind of drilling rigs you have?
A: We mainly did hydraulic driling rig for soils, pneumatic drilling rig for rocks, DTH drilling rig, big diameter drilling rig, engineering drilling rig, geological exploration drilling rig etc, so you can tell me your requirements, would recommend you the suitable one.

3. Q: What certificate you have?
A: CE, ISO, BV, TUV

4. Q: Do you offer training?
A: Each model we have supplementary instruction mannual, video for installation and operation, calling instruction, and working site instruction.

5. Q: How about the warranty?
A: We machine warranty is 1 year, used famous brand parts help you find locally; Also 3 spare parts center guarantee you get the spare parts in time.