Products
Micro Bore Units - MBU
Micro Bore Units
include/img/Micro Bore Units/Introduction/micro_bore_units_big.jpg
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) radially.
  •   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.
  •   Minimum diameter for finish boring is 20mm.
  •   Adjustment can be done directly while the tool is on the machine, thus reducing downtime or setting time.
  •   Standard products (80 variants) available for ID boring, back boring, OD turning and undercut machining 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
include/img/Micro Bore Units/Nomenclature/MBUbig1.jpg
Nomenclature Code Key for Ordering Fine Boring Bar with MBU
include/img/Micro Bore Units/Nomenclature/MBUbig2.jpg
MBU - Angular Mounting Type
include/img/Micro Bore Units/Angular Mounting Type/angular_mounting_type_big1.jpg
include/img/Micro Bore Units/Angular Mounting Type/angular_mounting_type_big2.jpg
include/img/Micro Bore Units/Angular Mounting Type/angular_mounting_type_big3.jpg
include/img/Micro Bore Units/Angular Mounting Type/angular_mounting_type_big5.jpg
include/img/Micro Bore Units/Angular Mounting Type/angular_mounting_type_big4.jpg
Specification Chart
All Left-Hand variants shown above.
All dimensions are in mm.
Sr. No Item Code Insert Db L1 F1 Dmin Mounting
Screw 		Insert
Screw 		Torx Spanner
LH RH
1 RT MBU ALW 02 14 RT MBU ARW 02 14 WC..0201.. 14 11.50 1.00 20.00 RTMS14 M2.0 T6/T8 RTS14
2 RT MBU ALC 04 14 RT MBU ARC 04 14 CC..04T0.. 14 11.50 1.00 20.00 RTMS14 M2.0 T6/T8 RTS14
3 RT MBU ALT 06T1 14 RT MBU ART 06T1 14 TC..06T1.. 14 11.50 0.20 20.00 RTMS14 M2.0 T6/T8 RTS14
4 RT MBU ALT 0601 14 RT MBU ART 0601 14 TC..0601.. 14 11.50 0.20 20.00 RTMS14 M2.0 T6/T8 RTS14
5 RT MBU ALC 06 16 RT MBU ARC 06 16 CC..0602.. 16 14.30 0.45 25.90 RTMS16 M2.5 T8/T10 RTS16
6 RT MBU ALT 06T1 16 RT MBU ART 06T1 16 TC..06T1.. 16 14.30 0.20 25.40 RTMS16 M2.0 T6/T10 RTS16
7 RT MBU ALT 0601 16 RT MBU ART 0601 16 TC..0601.. 16 14.30 0.20 25.40 RTMS16 M2.0 T6/T10 RTS16
8 RT MBU ALC 09 20 RT MBU ARC 09 20 CC..09T3.. 20 19.10 1.00 33.10 RTMS20 M3.5 T15/T10 RTS20
9 RT MBU ALT 09 20 RT MBU ART 09 20 TC..0902.. 20 19.10 1.00 33.10 RTMS20 M2.2 T7/T10 RTS20
10 RT MBU ALTP 09 20 RT MBU ARTP 09 20 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 1102 22 RT MBU ART 1102 22 TC..1102.. 22 23.00 1.10 42.60 RTMS22 M2.5 T8/T15 RTS22
14 RT MBU ALT 1103 22 RT MBU ART 1103 22 TC..1103.. 22 23.00 1.10 42.60 RTMS22 M2.5 T8/T15 RTS22
15 RT MBU ALTP 11 22 RT MBU ARTP 11 22 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 32 RT MBU ARC 12 32 CC..1204.. 32 33.30 1.00 60.60 RTMS32 M4.5 T20/3MM RTS32
18 RT MBU ALT 16 32 RT MBU ART 16 32 TC..16T3.. 32 33.30 1.20 60.60 RTMS32 M3.5 T15/3MM RTS32
19 RT MBU ALTP 16T3 32 RT MBU ARTP 16T3 32 TP..16T3.. 32 33.30 1.20 60.60 RTMS32 M3.5 T15/3MM RTS32
20 RT MBU ALTP 1604 32 RT MBU ARTP 1604 32 TP..1604.. 32 33.30 1.20 60.60 RTMS32 M4.0 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.
  •   Minimum diameter (Dmin) calculated based on 0.4mm insert nose radius.
  •   MBU variants with DC..0702.. insert 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
include/img/Micro Bore Units/Straight Mounting Type/straight_mounting_type_big1.jpg
include/img/Micro Bore Units/Straight Mounting Type/straight_mounting_type_big2.jpg
include/img/Micro Bore Units/Straight Mounting Type/straight_mounting_type_big3.jpg
include/img/Micro Bore Units/Straight Mounting Type/straight_mounting_type_big4.jpg
include/img/Micro Bore Units/Straight Mounting Type/straight_mounting_type_big5.jpg
Specification Chart
All Left-Hand variants shown above.
All dimensions are in mm.
Sr. No Item Code Insert Db L1 F1 Dmin Mounting
Screw 		Insert
Screw 		Torx Spanner
LH RH

1

RT MBU SLW 02 14

RT MBU SRW 02 14

WC..0201..

14

11.0

4.1

22.0

RTMS14

M2.0

T6/T8

RTS14

2

RT MBU SLC 04 14

RT MBU SRC 04 14

CC..04T0..

14

11.0

4.1

22.0

RTMS14

M2.0

T6/T8

RTS14

3

RT MBU SLT 06T1 14

RT MBU SRT 06T1 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 16

RT MBU SRC 06 16

CC..0602..

16

13.3

5.1

27.6

RTMS16

M2.5

T8/T10

RTS16

6

RT MBU SLT 06T1 16

RT MBU SRT 06T1 16

TC..06T1..

16

13.3

4.1

27.1

RTMS16

M2.0

T6/T10

RTS16

7

RT MBU SLT 0601 16

RT MBU SRT 0601 16

TC..0601..

16

13.3

4.1

27.1

RTMS16

M2.0

T6/T10

RTS16

8

RT MBU SLC 09 20

RT MBU SRC 09 20

CC..09T3..

20

18.3

7.2

37.1

RTMS20

M3.5

T15/T10

RTS20

9

RT MBU SLT 09 20

RT MBU SRT 09 20

TC..0902..

20

18.3

6.3

37.1

RTMS20

M2.2

T7/T10

RTS20

10

RT MBU SLTP 09 20

RT MBU SRTP 09 20

TP..0902..

20

18.3

6.3

37.1

RTMS20

M2.5

T8/T10

RTS20

11

RT MBU SLD 07 20

RT MBU SRD 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 1102 22

RT MBU SRT 1102 22

TC..1102..

22

22.1

7.2

49.1

RTMS22

M2.5

T8/T15

RTS22

14

RT MBU SLT 1103 22

RT MBU SRT 1103 22

TC..1103..

22

22.1

7.2

49.1

RTMS22

M2.5

T8/T15

RTS22

15

RT MBU SLTP 11 22

RT MBU SRTP 11 22

TP..1103..

22

22.1

7.2

49.1

RTMS22

M3.0

T10/T15

RTS22

16

RT MBU SLD 07 22

RT MBU SRD 07 22

DC..0702..

22

22.1

7.2

49.1

RTMS22

M2.5

T8/T15

RTS22

17

RT MBU SLC 12 32

RT MBU SRC 12 32

CC..1204..

32

32

10.3

69.6

RTMS32

M4.5

T20/3MM

RTS32

18

RT MBU SLT 16 32

RT MBU SRT 16 32

TC..16T3..

32

32

10.3

69.6

RTMS32

M3.5

T15/3MM

RTS32

19

RT MBU SLTP 16T3 32

RT MBU SRTP 16T3 32

TP..16T3..

32

32

10.3

69.6

RTMS32

M3.5

T15/3MM

RTS32

20

RT MBU SLTP 1604 32

RT MBU SRTP 1604 32

TP..1604..

32

32

10.3

69.6

RTMS32

M4.0

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.
  •   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
include/img/Micro Bore Units/ID Boring/application_id_boring_big1.jpg
include/img/Micro Bore Units/ID Boring/application_id_boring_big2.jpg
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
include/img/Micro Bore Units/OD Turning & Undercut/application_od_turning_and_undercut_big1.jpg
include/img/Micro Bore Units/OD Turning & Undercut/application_od_turning_and_undercut_big2.jpg
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
include/img/Micro Bore Units/Back Boring/application_back_boring_big1.jpg
include/img/Micro Bore Units/Back Boring/application_back_boring_big2.jpg
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
include/img/Micro Bore Units/ID Boring & Undercut/application_id_boring_and_undercut_big1.jpg
include/img/Micro Bore Units/ID Boring & Undercut/application_id_boring_and_undercut_big2.jpg
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.
include/img/Micro Bore Units/custmized Micro bore Unit/Customized MBU Big.jpg
Mounting Dimensions for Micro Bore Units
include/img/Micro Bore Units/Mounting Dimensions/mounting_dimmensions_for_mbu_big.jpg
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
  •   Position of the mounting holes mentioned above are for LH cutting Hand. For RH cutting hand, they will be mirrored.
  •   Mounting details mentioned in the above table depend on the bush diameter (Db) of the Micro Bore Unit.
  •   Please refer to the tables in the tabs of 'Angular Mounting Type' and 'Straight Mounting Type' to find the Bush Diameter (Db) of yours selected Micro Bore Unit.
MBU - Angular Mounting Type
include/img/Micro Bore Units/Working Dimensions/working_dimmensions_for_mbu_big1.jpg
Specification Chart
All dimensions are in mm.
sr no Db RT MBU ITEM CODE INSERTS D min D2 Bmin h1max Smin S1mean -ve range
(radial)		 +ve range
(radial)
LH RH
1 14 ALW 02 14 ARW 02 14 WC..020104 20 19 0.4 1.5 8.3 8.425 0.1 1.4
2 14 ALT 06T1 14 ART 06T1 14 TC..06T104 20 19 0.4 1.5 8.3 8.425 0.1 1.4
3 14 ALT 0601 14 ART 0601 14 TC..060104 20 19 0.4 1.5 8.3 8.425 0.1 1.4
4 14 ALC 04 14 ARC 04 14 CC..04T004 20 19 0.4 1.5 8.3 8.425 0.1 1.4
5 16 ALC 06 16 ARC 06 16 CC..060204 25.9 23 1.05 2 10.7 11.2 0.4 1.6
6 16 ALT 06T1 16 ART 06T1 16 TC..06T104 25.4 23 0.8 2 10.6 11.1 0.4 1.6
7 16 ALT 0601 16 ART 0601 16 TC..060104 25.4 23 0.8 2 10.6 11.1 0.4 1.6
8 20 ALC 09 20 ARC 09 20 CC..09T304 33.1 30 0.95 2.8 14.5 15.25 0.6 2.2
9 20 ALT 09 20 ART 09 20 TC..090204 33.1 30 0.95 2.8 14.5 15.25 0.6 2.2
10 20 ALTP 09 20 ARTP 09 20 TP..090204 33.1 30 0.95 2.8 14.5 15.25 0.6 2.2
11 20 ALD 09 20 ARD 09 20 DC..070204 33.1 30 0.95 2.8 14.5 15.25 0.6 2.2
12 22 ALC 09 22 ARC 09 22 CC..09T304 42.6 39.6 0.9 4.8 17.2 17.95 0.6 4.2
13 22 ALT 1102 22 ART 1102 22 TC..110204 42.6 39.6 0.9 4.8 17.2 17.95 0.6 4.2
14 22 ALT 1103 22 ART 1103 22 TC..110304 42.6 39.6 0.9 4.8 17.2 17.95 0.6 4.2
15 22 ALTP 11 22 ARTP 11 22 TP..110304 42.6 39.6 0.9 4.8 17.2 17.95 0.6 4.2
16 22 ALD 11 22 ARD 11 22 DC..070204 42.6 39.6 0.9 4.8 17.2 17.95 0.6 4.2
17 32 ALC 12 32 ARC 12 32 CC..120404 60.6 56.6 1.4 8 26.2 26.95 0.6 7.4
18 32 ALT 16 32 ART 16 32 TC..16T304 60.6 56.6 1.4 8 26.2 26.95 0.6 7.4
19 32 ALTP 16T3 32 ARTP 16T3 32 TP..16T304 60.6 56.6 1.4 8 26.2 26.95 0.6 7.4
20 32 ALTP 1604 32 ARTP 1604 32 TP..160404 60.6 56.6 1.4 8 26.2 26.95 0.6 7.4
MBU - Straight Mounting Type
include/img/Micro Bore Units/Working Dimensions/working_dimmensions_for_mbu_big2.jpg
Specification Chart
All dimensions are in mm.
sr no Db RT MBU ITEM CODE INSERTS D min D2 Bmin h1max Smin S1mean -ve range
(radial)		 +ve range
(radial)
LH RH
1 14 SLW 02 14 SRW 02 14 WC..020104 22 20.5 0.5 2 7.8 8.05 0.25 1.75
2 14 SLT 06T1 14 SRT 06T1 14 TC..06T104 22 20.5 0.5 2 7.8 8.05 0.25 1.75
3 14 SLT 0601 14 SRT 0601 14 TC..060104 22 20.5 0.5 2 7.8 8.05 0.25 1.75
4 14 SLC 04 14 SRC 04 14 CC..04T004 22 20.5 0.5 2 7.8 8.05 0.25 1.75
5 16 SLC 06 16 SRC 06 16 CC..060204 27.6 25.5 0.65 2.5 9.6 10 0.4 2.1
6 16 SLT 06T1 16 SRT 06T1 16 TC..06T104 27.1 25 0.65 2.5 9 9.4 0.4 2.1
7 16 SLT 0601 16 SRT 0601 16 TC..060104 27.1 25 0.65 2.5 9 9.4 0.4 2.1
8 20 SLC 09 20 SRC 09 20 CC..09T304 37.1 34.5 0.8 3.5 13.6 14.1 0.5 3
9 20 SLT 09 20 SRT 09 20 TC..090204 37.1 34.5 0.8 3.5 13.6 14.1 0.5 3
10 20 SLTP 09 20 SRTP 09 20 TP..090204 37.1 34.5 0.8 3.5 13.6 14.1 0.5 3
11 20 SLD 09 20 SRD 09 20 DC..070204 37.1 34.5 0.8 3.5 13.6 14.1 0.5 3
12 22 SLC 09 22 SRC 09 22 CC..09T304 49.1 46.5 0.8 6 16.4 16.9 0.5 5.5
13 22 SLT 1102 22 SRT 1102 22 TC..110204 49.1 46.5 0.8 6 16.4 16.9 0.5 5.5
14 22 SLT 1103 22 SRT 1103 22 TC..110304 49.1 46.5 0.8 6 16.4 16.9 0.5 5.5
15 22 SLTP 11 22 SRTP 11 22 TP..110304 49.1 46.5 0.8 6 16.4 16.9 0.5 5.5
16 22 SLD 11 22 SRD 11 22 DC..070204 49.1 46.5 0.8 6 16.4 16.9 0.5 5.5
17 32 SLC 12 32 SRC 12 32 CC..120404 69.6 67 0.8 10 25 25.5 0.5 9.5
18 32 SLT 16 32 SRT 16 32 TC..16T304 69.6 67 0.8 10 25 25.5 0.5 9.5
19 32 SLTP 16T3 32 SRTP 16T3 32 TP..16T304 69.6 67 0.8 10 25 25.5 0.5 9.5
20 32 SLTP 1604 32 SRTP 1604 32 TP..160404 69.6 67 0.8 10 25 25.5 0.5 9.5
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.
include/img/Micro Bore Units/Operating Instructions/pic1_big.jpg
  •   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.
include/img/Micro Bore Units/Operating Instructions/pic2_big.jpg
  •   See if the desired results are 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. One entire division movement of the inner MBU scale will give you 20 microns on diameter(i.e. 10 microns radially). Now use the vernier scale for fine 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).
include/img/Micro Bore Units/Operating Instructions/pic3_big.jpg
  •   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.
include/img/Micro Bore Units/Operating Instructions/pic4_big.jpg
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.