# 40 taper tooling



## PT Doc (Nov 17, 2018)

CAT40 tooling seems to be more readily available than NT40 from suppliers like MariTool and Glacern. Makes sense since Haas machines use CAT40. I have been reading a bit through old posts about modifying the drawbar and keys of a NT40 machine to convert it to use CAT40 tooling.

If you were able to buy a good quality 5hp milling machine with NT40 spindle taper, would you convert the machine to accept CAT40 tooling? I have neither NT40 nor CAT40 tooling at this time.

Thanks in advance.


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## Ulma Doctor (Nov 17, 2018)

i believe the taper is the same on both toolholders.
NMTB40 toolholder has a longer overall length
you can use a CAT40 in an NMTB40 spindle, but the converse is NOT, true


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## PT Doc (Nov 17, 2018)

Ulma Doctor said:


> i believe the taper is the same on both toolholders.
> NMTB40 toolholder has a longer overall length
> you can use a CAT40 in an NMTB40 spindle, but the converse is NOT, true



Yes, the taper is 3.5” per 12”. NT40 and CAT40 have the same taper. The NT40 is longer than the CAT40, so a longer drawbar would be needed.


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## Ulma Doctor (Nov 17, 2018)

PT Doc said:


> Yes, the taper is 3.5” per 12”. NT40 and CAT40 have the same taper. The NT40 is longer than the CAT40, so a longer drawbar would be needed.



yes sir!


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## plunger (Nov 18, 2018)

What difference has iso 40 got to cat and nt?


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## Liljoebrshooter (Nov 18, 2018)

I have a Gorton mill with a nt30 taper.  I believe the cat 30 has a metric thread also, otherwise it will fit the ntmb holder.


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## Ulma Doctor (Nov 18, 2018)

plunger said:


> What difference has iso 40 got to cat and nt?


the tapers are the same on all 3
the NMTB40 is the longest of the 3, and it is NOT interchangeable to iso40 or CAT40
BUT
the ISO40 and the CAT40 holders can be used in a NMTB40 spindle with modifications to the drawbar arrangement

the difference in the CAT40 and ISO40 is the size of the groove where the automatic tool changer grabs the toolholder
the toolholders may not be interchangeable on a CNC machine, but are interchangeable in a manual machine


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## Jason5555 (Nov 22, 2018)

I don't mean to hijak the thread but where does the 40FC (flash change) fall in line among them all? As I have a 4" Facemill with a Baker 40NT spindle on Ebay that came with a 40FC to 4mt adapter in the same lot. Both could fit in a 40NMTB correct?


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## warrjon (Nov 22, 2018)

My mill has a 40 taper and I use NT, ISO and BT40 tools.

The difference between BT and CAT 40 is - the flange for the tool loader is different both should work in an NT40 taper.

There are 2 draw bar threads 5/16 UNC and M16, I have both draw bars and tools but changing the draw bar requires a ladder, so I do not use the 5/16 tools,

My draw bar is long so will pull on a BT40 tool holder and the few ISO40 tools I have, the difference is the ISO40 has a spigot on the end and the BT40 does not.


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