Self-drilling anchor system are innovative and efficient construction components that combine drilling, grouting, and anchoring functions into a single integrated system. These rock anchor bolts are designed to simplify the installation process, reduce construction time, and enhance the stability of structures in various geological conditions. A self-drilling anchor bolt typically consists of several essential components, each playing a critical role in its performance:
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Threaded Hollow Anchor BarThe threaded hollow anchor bar forms the core structural element of the whole self-drilling anchor system. It provides the necessary load-bearing capacity and is designed to resist tension forces. The thread pattern on the rod allows for easy attachment of drill bits, nuts, plates, and other components. Self-drilling anchor bolts can be categorized based on their threading patterns. Two common types include R-Thread Self-Drilling Anchor Bolts and T-Thread Self-Drilling Anchor Bolts.
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R-Thread Anchor Bolt Technial Data
 |
R25N |
R32N |
R32S |
R38N |
R51L |
R51N |
T76N |
T76S |
Outside diameter |
25 |
32 |
32 |
38 |
51 |
51 |
76 |
76 |
Internal diameter |
14 |
19 |
16 |
19 |
36 |
33 |
52 |
45 |
Ultimate load |
200 |
280 |
360 |
500 |
550 |
800 |
1600 |
1900 |
Yield load |
150 |
230 |
280 |
400 |
450 |
630 |
1200 |
1500 |
Tensile strength, |
800 |
800 |
800 |
800 |
800 |
800 |
800 |
800 |
Yield strength, |
650 |
650 |
650 |
650 |
650 |
650 |
650 |
650 |
Weight(Kg/m) |
2.3 |
3.2 |
3.6 |
5.5 |
6.5 |
8.0 |
16.0 |
19.7 |
Thread type |
ISO 10208 |
ISO 1720 |
MAI T76 Standard |
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Steel grade |
En10083-1 (Alloy structure steel) |
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Compared to carbon steel, alloy structure steel has high anti-corrosion capacity and high mechanical. |
R thread anchor bar or called rock rod, soil nail, which is a kind of threaded hollow bar, bar surface with an rope thread according to ISO 10208 & 1720. It was firstly invented by MAI on 1960S to solve the low construction speed on complicated underground works, nowadays; it is very popular all around the world.
Thread size: R25, R32, R38, R51, T76.
Thread standard: ISO10208, ISO1720 etc.
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T-Thread Anchor Bolt Technial Data
Bar Type |
Outside Diameter |
Inside Diameter |
Cross section |
Ultimate Load |
Yield Point |
Weight |
Thread Left/ |
30/11 |
30 |
11 |
446 |
320 |
260 |
3.3 |
Lift or right |
30/14 |
30 |
14 |
395 |
260 |
220 |
2.9 |
Lift or right |
30/16 |
30 |
16 |
382 |
220 |
180 |
2.7 |
Lift or right |
40/16 |
40 |
16 |
879 |
660 |
525 |
7.0 |
Lift or right |
40/20 |
40 |
20 |
726 |
539 |
430 |
5.6 |
Lift or right |
52/26 |
52 |
26 |
1337 |
929 |
730 |
10.0 |
Lift or right |
73/53 |
73 |
53 |
1160 |
1630 |
970 |
12.3 |
Lift or right |
73/56 |
73 |
56 |
1094 |
1414 |
785 |
11.1 |
Lift or right |
73/45 |
73 |
45 |
2265 |
1630 |
1180 |
17.8 |
Lift or right |
T thread anchor bar surface with a trapezoidal thread, this design of connection is much stronger and reliable when compared with rope thread, we supply full sizes from T30 to T103.
Thread size: T30, T40, T52, T73, T103, T127, T130.
Thread standard: ISO10208, ISO1720 etc.
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Anchor Plate
 |
R25N |
R32N |
R32S |
R38N |
R51L |
R51N |
T76N |
T76S |
Dimention(mm) |
150*150 |
200*200 |
200*200 |
200*200 |
200*200 |
250*250 |
250*250 |
250*250 |
Thickness(mm) |
8 |
10 |
12 |
12 |
20 |
40 |
40 |
40 |
Hole diameter(mm) |
30 |
35 |
35 |
41 |
60 |
60 |
80 |
80 |
Weight(KG/PC) |
1.4 |
3 |
3.7 |
3.6 |
8.8 |
18.5 |
18 |
18 |
Cold deformed with geometry |
Anchor Coupling
 |
R25N |
R32N |
R32S |
R38N |
R51L |
R51N |
T76N |
T76S |
Outside diameter(mm) |
35 |
42 |
42 |
52 |
63 |
63 |
95 |
95 |
Length(mm) |
120 |
145 |
160or190 |
180 |
180 |
200 |
200 |
200 |
Weight |
0.45 |
0.7 |
0.75 |
1.4 |
1.7 |
1.9 |
6.4 |
6.4 |
Machined steel coupling middle stop |
The hollow bar is continuously threaded, it can be cut and coupled anwhere along its length.
The coupling enables direct end-to-end energy transmission between each bar, reducing losses and ensuring maximum percussive engergy at the drill bit.
Drill Bit
 |
R25N |
R32N |
R32S |
R38N |
R51L |
R51N |
T76N |
T76S |
diameter(mm) |
41,51 |
51,76,90 |
90,100,110,115,130 |
130,150,160,180,200 |
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Hardened cross bit |
Hardened cross bit for loose to medium dense condition with small boulders. |
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Tungsten cross bit |
TC cross bit for soft to medium rock for mations |
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Hardened button bit |
Hardened buuton bit for unconsolidated rock with boulders. |
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Tungsten carbon button bit |
Button bit with TC inserts for medium rock for formations. |
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Hardened arch bit |
Hardened drill bit with optimized geometry for uncon solid dated soil |
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Tungsten carbon arch bit |
TC drill bit with optimized geometry for soft to medium rock formations. |
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Hardened drop center bit |
Hardened cross bit for loose to medium dense ground conditions |
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TC drop center bit |
TC drill bit for soft to medium rock formations. |
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Casting clay bit |
Casting clay bit with optimized geometry for very soft to soft caly. |
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Machined steel bit or Casring steel bit |
The sacrificial drill bit is an important part of the self drilling anchoring system.
Choose suitable bits according to different soil type.
Anchor Nut
 |
R25N |
R32N |
R32S |
R38N |
R51L |
R51N |
T76N |
T76S |
Key size(mm) |
41 |
46 |
46 |
50 |
75 |
75 |
100 |
100 |
Length(mm) |
135 |
45 |
45 |
55 |
70 |
70 |
80 |
80 |
Weight(kg/pc) |
0.25 |
0.35 |
0.35 |
0.5 |
1.55 |
1.55 |
3.6 |
3.6 |
Machined steel nut or casting steel nut |
The hexagonal and spherical nuts are made from high precision steel (40Cr,HRC 20-25) to meet the stringent demands on anchor specifications and the daily uses of reinforcement work.
All nuts exceed the ultimate strength of the rod.
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