19

100

80

60

40

20

0

48

12

16

20

24

28

32

4
8

12
16
20
24
28
32

4-15

19-26
33-45
42-57
59-80
72-98

81-111

90-122

140-530
670-920

1,170-1,590

1,480-2,010

2,080-2,830
2,540-3,460
2,860-3,920

3,180-4,310

OTHERS

APPLICATION EXAMPLES

y

 Rotation Speed of Bit

Standard speed is 15−20m/min. 

Refer to the following figure for rotation. 

Select the range of uniform rotation during drilling.

Q : Air supply (m

3

/min)

D : Inside diameter of casing (mm)

d : Outside diameter of jacket or hammer (mm)

V : Air speed 1,100−1,500 (m/min)

y

 Setting Compressor

a

 Pressure

 • Set between 0.7 to 1.0MPa (100−150psi)

 • Consider the depth of underground water when drilling

  through the layer.

  (In case of 30m (90 ft) depth, add 0.3MPa (45psi)

  to the air pressure.)

 • Do not set over 1.5MPa (225psi)

a

 Air Consumption

 • Set the air supply usingthe following formula.

Q=

V(D

2

–d

2

)

1273500

Bit Rotation Speed

Rot

at

io

n S

p

e

e

d (

min

-1

)

Nominal Size (in.)

Recommended Air Consumption

Nominal Size

(in.)

Air Supply

(m

3

/min)

(cfm)

a

 ULTRA MAXBIT for RD Pile

• Face of the pilot bit is located at same level of ring bit.

(Pilot bit does not protrude from the ring bit like other 

standard ULTRA MAXBIT system)

This structure make the system stronger against the 

heavy weight from RD pile.

• Ring bit is bigger than the diameter of "Threaded sleeve 

splice" shown below illustration for soother drilling.

• Minimum width of the ring bit is same as the width of 

casing pipe to retain enough strength of RD pile.

Minimum

wall thickness

Load

Treaded

sleeve splice

RD pile pipe

Flat bottom