NMTB Tool Holders - NMTB30, NMTB40, NMTB50

NMTB Tool Holders – NMTB30, NMTB40, NMTB50 2017-06-21T16:38:19+00:00

nmtb-tool-holdersNMTB tool holders (National Machine Tool Builders Association) are single-flanged tool holders and are often referred as Quick-Change.

NMTB tool holders come in different sizes: NMTB 30, NMTB 40, NMTB 50. The number designates the size of the taper: the higher the number is, the bigger is the taper. They come in imperial sizes.

The NMTB shank was developed for use in the NMTB spindle, which uses a draw bar to pull the shank up into the spindle. NMTB designs are relatively old; however they do fit modern machines too.

What differs NMTB tool holders from other tooling is the drawbar: on the small end of the taper there is a cylindrical extension. Also, NMTB tool holders come single-flanged with a simple flange with 2 flat keyways.

The flange diameter, flange thickness and distance from the gage line of the taper to the outward face of the flange are not critical dimensions for NMTB  tool holders and therefore can vary in products made by different manufacturers.

Quick change tooling used on CNC machines uses a pull stud on each of the tools and a claw device that lock on the stud and pulls it into the spindle. Most (but not all) NMTB shanks are compatible with the corresponding size Erickson Quick Change Spindles.

It depends on the manufacturer of the NMTB tool holder, and all tool holders made by Erickson will work fine (they are marked Quick Change).

Other brands in most cases will also work fine, but you may choose to find additional information on sizes of some parts of tool holders as they might be slightly different and sometimes may not fit in your quick change spindle.

If you are using machinery made in the middle of 20th century, most likely you are looking for NMTB tooling (or R8). Though being relatively old, they provide high stability and reliability.

NMTB Tool Holders (Quick Change) Shank

ANSI B5.18, National Machine Tool Builders’ Association, 1927. DIN 2080 / IS 2340, ISO R 290-2583
Also called Quick Change, NMTB, MM, National Standard, American Standard Machine Taper, etc.

Below you can find the table of sizes:

ANSI B5.18 (from Kennametal catalog 7060)

Size

D1

D2

D3

D4 max

D5*

L1

L2

L3

L4

L5

L6

G

30

1.250
[31.75]

0.655
[16.24]

0.673
[17.09]

1.380
[35.05]

1.812
[46.02]

2.690
[68.33]

0.810
[20.57]

0.125
[3.18]

0.076
[1.93]

0.344
[8.74]

0.359
[9.12]

1/2-13
thread

40

1.750
[44.45]

0.935
[23.75]

0.984
[25.00]

1.890
[48.0]

2.500
[63.5]

3.690
[93.73]

1.180
[29.97]

0.188
[4.78]

0.076
[1.93]

0.313
[7.95]

?

5/8-11
thread

50

2.750
[69.85]

1.495
[37.97]

1.545
[39.24]

2.760
[68.6]

3.500
[88.9]

5.000
[127.0]

1.000
[25.4]

0.188
[4.78]

0.141
[3.58]

0.453
[11.51]

?

1-8
thread

* These are Kennametal dimensions. D5 varies with different mfgs.

ISO R 297-2583 and DIN 2080

Size

D1

~

D3

D4 max

D5

L1

L2

~

L4

L5

L6 min

G

30

31.75

~

?

?

50

68.39

?

~

1.62

8

?

M12

DO40

44.45

~

22.63

50

63

93.40

?

~

1.6

10

11.0

M16

45

57.15

~

?

?

80

106.8

?

~

3.2

12

?

M20

DT50

69.85

~

34.25

78

97.5

126.8

25

~

3.2

12

16.0

M24

 

Tool holders built in those two types are usually interchangeable, but there are few differences. Keep this in mind when choosing the right one.

Cat Tool Holders, BT Tool Holders & NMBT Tool Holders

Important note: They NOT the same, same taper, different flanging, different key lugs.

Depending on what your spindle is like as to IF they are interchangeable.  IF  you have a nmtb30 and wanted to do a tool changer you could fit Cat30 or BT30 tool holders by changing out the lug bars. That way you would have the tool holder slots to work with on the tool holders.

Sometimes people rework there cat spindle to hold BT tool holders sometimes the opposite depending on how much of what tool holders are available. IF you change the holders you have to also change the tool holder fingers in the atc.

NMBT Tool Holders: Bottom Line

NMBT tool holders are one of the essential types of tool holders that have uniquenesses that set them apart from such tool holders as Cat, BT, and HSK.

Depending on the application and machine that you are using, and what you are wanting to accomplish as far as performance, capabilities, precision and more- Tool Holder Exchange can help you to find the perfect NMBT tool holder.

We offer a large selection of NMBT tooling and have an experienced staff that can point you in the right direction and give you the best prices on the name brand machine tooling you need.

If you are in need of NMTB tool holders or if you have NMTB tool holders you want to get off your hands, please contact us using the form on this page.

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