symmetric drilling system
Rock drilling tools manufacturer ROSCHEN , Symmetric 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.
DTH hammer's impact energy is transferred through the pilot and ring bits, crushing rock, part of impact energy advances casing. 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. Drilling continues to the desired depth in the bedrock using a conventional drilling.
Drilling through loose, unconsolidated material such as soil, clay, silt, sand, gravel, and boulders is the so-called overburden, which is often problematic due to the tendency of the earth to cave in behind the drill bit. The Symmetric Casing Drilling System is just to drill in rock formation where contains some such ovals and fractures, and it represents the latest technology in simultaneous overburden casing drilling systems.
Application Range: Suitable for drilling water wells, geothermal wells, 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.
| Casing Tube OD |
Ring Bit OD |
Min. Casing Shoe ID |
Pilot Bit Diameter |
Hammer Shank Style |
| mm |
inch |
mm |
inch |
mm |
inch |
mm |
inch |
| 108~127 |
4 1/4 ~ 5 |
118~134 |
4 5/8 ~ 5 1/4 |
78~101 |
3 1/16 ~ 4 |
77~92 |
3 1/32 ~ |
DHD3.5, Cop34, Mission 30 |
| 3 5/8 |
| 140~146 |
5 1/2 ~ |
150 ~156 |
5 27/64 ~ |
94~117 |
3 45/64 ~ |
105~124 |
4 1/8 ~ |
DHD340A, SD4, QL40, Mission40 |
| 5 3/4 |
6 1/8 |
4 5/8 |
4 57/64 |
| 168~178 |
6 5/8 ~ 7 |
178~195 |
7 ~ 7 5/8 |
121~150 |
4 3/4 ~ 5 7/8 |
125~156 |
4 59/64 ~ |
DHD350R, SD5, QL50, Mission50 |
| 6 9/64 |
| 194~219 |
7 5/8 ~ |
203~234 |
8 ~ 9 1/4 |
148~190 |
5 5/8 ~ |
150~203 |
5 7/8 ~ 8 |
DHD360, SD6, QL60, Mission60 |
| 8 5/8 |
7 1/2 |
| 219~325 |
8 5/8 ~ |
235~348 |
9 1/4 ~ |
190~284 |
7 1/2 ~ |
165~306 |
6 1/2 ~ |
DHD380, QL80, SD8, Mission 80 |
| 12 3/4 |
13 11/16 |
11 3/16 |
12 3/64 |
| 244~406 |
9 5/8 ~16 |
273~440 |
10 3/4 ~ |
210~364 |
8 1/4 ~ |
190~340 |
7 1/2 ~ |
SD10, Numa100 |
| 17 5/16 |
14 5/16 |
13 25/64 |
| 406~558 |
16 ~ 22 |
419~590 |
16 1/2 ~ |
328~514 |
12 27/32 ~ |
340~440 |
13 25/64 ~ |
SD12, DHD112, Numa120, Numa125 |
| 23 1/4 |
20 1/4 |
17 3/8 |
| 508~762 |
20 ~ 30 |
526 ~798 |
20 45/64 ~ |
412~716 |
16 1/4 ~ |
470~685 |
18 1/2 ~ |
SUP205 |
| 31 7/16 |
28 3/16 |
26 31/32 |
| 609~762 |
24 ~ 30 |
637~798 |
25 ~ |
513~716 |
20 3/16 ~ |
540~685 |
21 1/4 ~ |
SUP245 |
| 31 7/16 |
28 3/16 |
26 31/32 |
| 863 |
34 |
900 |
35 7/16 |
815 |
32 3/32 |
785 |
30 27/32 |
SUP325 |
ROSCHEN GROUP is professional in manufacturing and supplying quality bq casing advancer as one of the leading manufacturers and suppliers in China. We now bring you high quality bq casing advancer for sale, competitive in its excellent performance and high precision. Please rest assured to buy.
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