Micro Bore Units - MBU
Micro Bore Units
Facts & Advantages
  •   Precision Finish Boring Unit with high accuracy & repeatability.
  •   Used for machining close tolerances.
  •   Facilitates precision adjustment with least count of 1 micron (0.001mm) .
  •   Can be mounted in blind holes with provision of adjustment from the top.
  •   Self-clamping / Self-locking units i.e. no tightening & loosening of screws involved.
  •   Pre-loaded (pre-tensioned) assembly guaranteeing almost zero backlash.
  •   Adjustment can be done directly while the tool is on the machine, thus reducing downtime or setting time.
  •   Available in a wide range of variants and inserts enabling high degree of flexibility & a variety of precision boring applications.
  •   Directly interchangeable in the same tools as R/L148C or T-Max U fine boring unit or equivalent.
Nomenclature Code Key for Ordering MBU
Nomenclature Code Key for Ordering Fine Boring Bar with MBU
MBU - Angular Mounting Type
Specification Chart
All dimensions are in mm.
Sr. No Item Code Insert Db L1 F1 Dmin Mounting
Screw
Insert
Screw
Torx Spanner Stock
LH RH LH RH
1 RT MBU ALW 02 RT MBU ARW 02 WC..0201.. 14 11.50 1.00 20.00 RTMS14 M2.0 T6/T8 RTS14

2 RT MBU ALC 04 RT MBU ARC 04 CC..04T0.. 14 11.50 1.00 20.00 RTMS14 M2.0 T6/T8 RTS14

3 RT MBU ALT 06 14 RT MBU ART 06 14 TC..06T1.. 14 11.50 1.00 20.00 RTMS14 M2.0 T6/T8 RTS14

4 RT MBU ALT 0601 14 RT MBU ART 0601 14 TC..0601.. 14 11.50 1.00 20.00 RTMS14 M2.0 T6/T8 RTS14

5 RT MBU ALC 06 RT MBU ARC 06 CC..0602.. 16 14.30 0.45 25.90 RTMS16 M2.5 T8/T10 RTS16

6 RT MBU ALT 06 RT MBU ART 06 TC..06T1.. 16 14.30 0.20 25.40 RTMS16 M2.0 T6/T10 RTS16

7 RT MBU ALT 0601 RT MBU ART 0601 TC..0601.. 16 14.30 0.20 25.40 RTMS16 M2.0 T6/T10 RTS16

8 RT MBU ALC 09 RT MBU ARC 09 CC..09T3.. 20 19.10 1.00 33.10 RTMS20 M3.5 T15/T10 RTS20

9 RT MBU ALT 09 RT MBU ART 09 TC..0902.. 20 19.10 1.00 33.10 RTMS20 M2.2 T7/T10 RTS20

10 RT MBU ALTP 09 RT MBU ARTP 09 TP..0902.. 20 19.10 1.00 33.10 RTMS20 M2.5 T8/T10 RTS20

11 RT MBU ALD 07 20 RT MBU ARD 07 20 DC..0702.. 20 19.10 1.00 33.10 RTMS20 M2.5 T8/T10 RTS20

12 RT MBU ALC 09 22 RT MBU ARC 09 22 CC..09T3.. 22 23.00 1.10 42.60 RTMS22 M3.5 T15 RTS22

13 RT MBU ALT 11 RT MBU ART 11 TC..1102.. 22 23.00 1.10 42.60 RTMS22 M2.5 T8/T15 RTS22

14 RT MBU ALT 1103 RT MBU ART 1103 TC..1103.. 22 23.00 1.10 42.60 RTMS22 M2.5 T8/T15 RTS22

15 RT MBU ALTP 11 RT MBU ARTP 11 TP..1103.. 22 23.00 1.10 42.60 RTMS22 M3.0 T10/T15 RTS22

16 RT MBU ALD 07 22 RT MBU ARD 07 22 DC..0702.. 22 25.00 2.30 42.60 RTMS22 M2.5 T8/T15 RTS22

17 RT MBU ALC 12 RT MBU ARC 12 CC..1204.. 32 33.30 1.00 60.60 RTMS32 M4.5 T20/3MM RTS32

18 RT MBU ALT 16 RT MBU ART 16 TC..16T3.. 32 33.30 1.20 60.60 RTMS32 M3.5 T15/3MM RTS32

19 RT MBU ALTP 16 RT MBU ARTP 16 TP..16T3.. 32 33.30 1.20 60.60 RTMS32 M3.5 T15/3MM RTS32

Notes
  •   Micro Bore Units are delivered with all required spares such as insert screw, mounting screws, spanner, torx keys & allen keys.
  •   Inserts are not included with Micro Bore Units.
  •   Spares sold separately as well and can be ordered as per the ordering code shown in above table.
  •   In the above table, denotes ready in stock & denotes lead time of one week.
  •   Minimum diameter (Dmin) calculated based on 0.4mm insert nose radius.
  •   MBU variants AL/RD 07 are specially designed for close tolerance undercut applications.
  •   Maximum recommended material removal is 0.5mm diametrically.
  •   Customized MBU for special requirements can also be provided but will be made to order with a lead time of 3-6 weeks.
MBU - Straight Mounting Type
Specification Chart
All dimensions are in mm.
Sr. No Item Code Insert Db L1 F1 Dmin Mounting
Screw
Insert
Screw
Torx Spanner Stock
LH RH LH RH

1

RT MBU SLW 02

RT MBU SRW 02

WC..0201..

14

11.0

4.1

22.0

RTMS14

M2.0

T6/T8

RTS14

2

RT MBU SLC 04

RT MBU SRC 04

CC..04T0..

14

11.0

4.1

22.0

RTMS14

M2.0

T6/T8

RTS14

3

RT MBU SLT 06 14

RT MBU SRT 06 14

TC..06T1..

14

11.0

4.1

22.0

RTMS14

M2.0

T6/T8

RTS14

4

RT MBU SLT 0601 14

RT MBU SRT 0601 14

TC..0601..

14

11.0

4.1

22.0

RTMS14

M2.0

T6/T8

RTS14

5

RT MBU SLC 06

RT MBU SRC 06

CC..0602..

16

13.3

5.1

27.6

RTMS16

M2.5

T8/T10

RTS16

6

RT MBU SLT 06

RT MBU SRT 06

TC..06T1..

16

13.3

4.1

26.1

RTMS16

M2.0

T6/T10

RTS16

7

RT MBU SLT 0601

RT MBU SRT 0601

TC..0601..

16

13.3

4.1

26.1

RTMS16

M2.0

T6/T10

RTS16

8

RT MBU SLC 09

RT MBU SRC 09

CC..09T3..

20

18.3

7.2

37.1

RTMS20

M3.5

T15/T10

RTS20

9

RT MBU SLT 09

RT MBU SRT 09

TC..0902..

20

18.3

6.3

37.1

RTMS20

M2.2

T7/T10

RTS20

10

RT MBU SLTP 09

RT MBU SRTP 09

TP..0902..

20

18.3

6.3

37.1

RTMS20

M2.5

T8/T10

RTS20

11

RT MBU SLDU 07 20

RT MBU SRDU 07 20

DC..0702..

20

18.3

6.3

37.1

RTMS20

M2.5

T8/T10

RTS20

12

RT MBU SLC 09 22

RT MBU SRC 09 22

CC..09T3..

22

22.1

7.2

49.1

RTMS22

M3.5

T15

RTS22

13

RT MBU SLT 11

RT MBU SRT 11

TC..1102..

22

22.1

7.2

49.1

RTMS22

M2.5

T8/T15

RTS22

14

RT MBU SLT 1103

RT MBU SRT 1103

TC..1103..

22

22.1

7.2

49.1

RTMS22

M2.5

T8/T15

RTS22

15

RT MBU SLTP 11

RT MBU SRTP 11

TP..1103..

22

22.1

7.2

49.1

RTMS22

M3.0

T10/T15

RTS22

16

RT MBU SLDU 07 22

RT MBU SRDU 07 22

DC..0702..

22

22.1

7.2

49.1

RTMS22

M2.5

T8/T15

RTS22

17

RT MBU SLC 12

RT MBU SRC 12

CC..1204..

32

32

10.3

69.6

RTMS32

M4.5

T20/3MM

RTS32

18

RT MBU SLT 16

RT MBU SRT 16

TC..16T3..

32

32

10.3

69.6

RTMS32

M3.5

T15/3MM

RTS32

19

RT MBU SLTP 16

RT MBU SRTP 16

TP..16T3..

32

32

10.3

69.6

RTMS32

M3.5

T15/3MM

RTS32

Notes
  •   Micro Bore Units are delivered with all required spares such as insert screw, mounting screws, spanner, torx keys & allen keys.
  •   Inserts are not included with Micro Bore Units.
  •   Spares sold separately as well and can be ordered as per the ordering code shown in above table.
  •   In the above table, denotes ready in stock & denotes lead time of one week.
  •   Minimum diameter (Dmin) calculated based on 0.4mm insert nose radius.
  •   MBU variants SL/RDU 07 are specially designed for close tolerance undercut applications.
  •   Maximum recommended material removal is 0.5mm diametrically.
  •   Customized MBU for special requirements can also be provided but will be made to order with a lead time of 3-6 weeks.
Illustrative Applications of Fine Boring using Micro Bore Units
ID Boring Application using Micro Bore Units
Notes
  •   Minimum Diameter ØD = Ø20.0mm
  •   Standard range of Fine Boring Tools for ID boring application are available from Renuka Tools. Click here know more.
OD Turning & Undercut Machining Application using Micro Bore Units
Notes
  •   Minimum Diameter ØD = Ø12.0mm
  •   Fine Boring Tools for OD Turning & Undercut Machining application will be tailor made as per requirements.
  •   Lead time of 2-3 weeks.
Back Boring Application using Micro Bore Units
Notes
  •   Minimum Diameter ØD = Ø22.0mm
  •   Fine Boring Tools for Back Boring application will be tailor made as per requirements.
  •   Lead time of 2-3 weeks.
ID Boring & Undercut Machining Application using Micro Bore Units
Notes
  •   Minimum Diameter ØD = Ø37.1mm
  •   Fine Boring Tools for ID Boring & Undercut Machining application will be tailor made as per requirements.
  •   Lead time of 2-3 weeks.
Customized Micro Bore Units
  •   Customized Micro Bore Unit designed and manufactured at Renuka Tools® for grooving application.
  •   Customized boring bar also designed and manufactured at Renuka Tools ® for this special application.
Mounting Dimensions for Micro Bore Units
Specification Chart
All dimensions are in mm.
Detail Sr.No. DbH7 d1 d2 d3 h3 h4 h5 Th hc T

A

1

14.0

16.0

3.7

2.7

9.3

2.8

1.2

8.0

8.65 ±0.02

M2.5

2

16.0

19.0

4.6

3.2

11.5

2.8

1.6

9.0

9.65 ±0.02

M3.0

3

20.0

25.0

4.6

3.2

15.5

4.0

1.6

9.0

12.50 ±0.05

M3.0

4

22.0

30.0

6.5

4.3

24.0

5.0

1.8

13.0

15.40 ±0.05

M4.0

B

5

32.0

46.0

11.9

5.4

33.0

6.3

-

16.0

23.00 ±0.05

M5.0

Notes
  •   Mounting details mentioned in the above table depend on the bush diameter (Db) of the Micro Bore Unit.
  •   Please refer to tables on page no. 4 & 5 to find the Bush Diameter (Db) of your selected Micro Bore Unit.
  •   Please refer to tables for angular and straight mounting type MBU to find the Bush Diameter (Db) of your selected Micro Bore unit
MBU - Angular Mounting Type
Specification Chart
All dimensions are in mm.
Sr.No. RT MBU Item Code Insert Dmin D2 Bmin h1max S1min

1

AL/RW 02

WC.. 020104

20.0

19.0

0.50

1.5

8.3

2

AL/RC 04

CC.. 04T004

20.0

19.0

0.50

1.5

8.3

3

AL/RT 06 14

TC.. 06T104

20.0

19.0

0.50

1.5

8.3

4

AL/RT 0601 14

TC.. 060104

20.0

19.0

0.50

1.5

8.3

5

AL/RC 06

CC.. 060204

25.9

22.0

1.65

2.0

10.7

6

AL/RT 06

TC.. 06T104

25.4

22.0

1.45

2.0

10.6

7

AL/RT 0601

TC.. 060104

25.4

22.0

1.45

2.0

10.6

8

AL/RC 09

CC.. 09T304

33.1

28.5

2.30

2.8

14.5

9

AL/RT 09

TC.. 090204

33.1

28.5

2.30

2.8

14.5

10

AL/RTP 09

TP.. 090204

33.1

28.5

2.30

2.8

14.5

11

AL/RD 07 20

DC.. 070204

33.1

28.5

2.30

2.8

14.5

12

AL/RC 09 22

CC.. 09T304

42.6

38.0

2.30

4.8

17.2

13

AL/RT 11

TC.. 110204

42.6

38.0

2.30

4.8

17.2

14

AL/RT 1103

TC.. 110304

42.6

38.0

2.30

4.8

17.2

15

AL/RTP 11

TP.. 110304

42.6

38.0

2.30

4.8

17.2

16

AL/RD 07 22

DC.. 070204

42.6

38.0

2.30

4.8

17.2

17

AL/RC 12

CC..120404

60.6

55.0

2.80

8.0

26.2

18

AL/RT 16

TC.. 16T304

60.6

55.0

2.80

8.0

26.2

19

AL/RTP 16

TP.. 16T304

60.6

55.0

2.80

8.0

26.2

MBU - Straight Mounting Type
Specification Chart
All dimensions are in mm.
Sr.No. RT MBU Item Code Insert Dmin D2 Bmin h1max S1min

1

SL/RW 02

WC.. 020104

22.0

21.0

0.50

2.0

10.3

2

SL/RC 04

CC.. 04T004

22.0

21.0

0.50

2.0

10.3

3

SL/RT 06 14

TC.. 06T104

22.0

21.0

0.50

2.0

10.3

4

SL/RT 0601 14

TC.. 060104

22.0

21.0

0.50

2.0

10.3

5

SL/RC 06

CC.. 060204

27.6

26.0

0.55

2.5

9.6

6

SL/RT 06

TC.. 06T104

26.1

25.0

0.5

1.8

9.0

7

SL/RT 0601

TC.. 060104

26.1

25.0

0.5

1.8

9.0

8

SL/RC 09

CC.. 09T304

37.1

34.5

1.30

3.5

13.6

9

SL/RT 09

TC.. 090204

37.1

34.5

1.30

3.5

13.6

10

SL/RTP 09

TP.. 090204

37.1

34.5

1.30

3.5

13.6

11

SL/RDU 07 20

DC.. 070204

37.1

34.5

1.30

3.5

13.6

12

SL/RC 09 22

CC.. 09T304

49.1

46.5

1.30

6.0

16.4

13

SL/RT 11

TC.. 110204

49.1

46.5

1.30

6.0

16.4

14

SL/RT 1103

TC.. 110304

49.1

46.5

1.30

6.0

16.4

15

SL/RTP 11

TP.. 110304

49.1

46.5

1.30

6.0

16.4

16

SL/RDU 07 22

DC.. 070204

49.1

46.5

1.30

6.0

16.4

17

SL/RC 12

CC..120404

69.6

67.0

1.30

10.0

25.0

18

SL/RT 16

TC.. 16T304

69.6

67.0

1.30

10.0

25.0

19

SL/RTP16

TP.. 16T304

69.6

67.0

1.30

10.0

25.0

Operating Instructions
  •   Mount the Micro Bore Unit properly in the finish boring tool supplied by Renuka Tools. This can be easily done by simply tightening the mounting screws in a proper manner (Pic1).In case the tool is of any other brand ensure that the manufacturer adheres to the mounting instructions provided by Renuka Tools. Else, it might result in non-efficient working or even tool failure.
  •   Set the required diameter before clamping the tool on the machine, ideally on a tool pre-setter, or else with the help of a precise dial indicator (Pic2). During this setting, ensure that any one scale marking on the MBU inner scale coincides exactly with the extreme end marking on the outer vernier scale. This will automatically match some other inner scale marking with the other extreme end of the outer vernier scale (Pic3). This will help the user to quickly adjust after initial trial of tool.
  •   See if the desired results obtained by running the tool on the machine. In case of any deviation in the desired results, kindly use the spanner for adjustment. For increasing the diameter, rotate in clockwise direction and for decreasing, rotate in counter-clockwise direction. The least count of the inner MBU scale is 20microns on diameter (i.e. 10 microns radially). Now use the vernier scale for adjustment. If the diameter reading has to be increased, kindly match the adjacent marking (of left side) with the nearest vernier scale marking. This will result in increase of 2 microns on the diameter (i.e. 1 micron radially) (Pic 3.1 Zoomed). For reduction of diameter, follow the same procedure in the opposite direction (Pic 3.2 Zoomed).
  •   Maximum diameter adjustment can be checked from the rear end of the spanner (Pic4). Do not exceed the maximum limit as it may cause permanent damage to the unit.
Precautionary Measures
  •   Due to constraints in the assembly tolerances, it is recommended that units, if damaged, are returned to Renuka Tools for assessment/repair in a controlled environment. Commercials for repair can only be determined after detailed assessment of the damaged unit.
  •   Renuka Tools Micro Bore Unit cannot be adjusted beyond its range and the maximum range can be checked from the thickness of the end portion of the spanner provided along with the unit. Exceeding the range might result in permanent damage to the unit.
  •   Kindly change the mounting screws and insert screws ahead in time to avoid accidents.
  •   In case of any observed decrease in accuracy over the time of usage, kindly request Renuka Tools for servicing the unit.