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Author Topic: CAT30 vs BT30 vs NMTB30 vs ????  (Read 26893 times)

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CAT30 vs BT30 vs NMTB30 vs ????
« on: August 10, 2009, 05:17:16 PM »
Are CAT30/BT30/NMTB30 the same, different, interchangeable?

Regards,
Ray L.
Regards,
Ray L.

vmax549

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Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #1 on: August 10, 2009, 05:29:11 PM »
NOT the same, same taper, different flanging, different key lugs.

Depending on what your spindle is like as to IF they are interchangeable.  IF I had a nmtb30 and wanted to do a tool changer I would 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 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.

HOPE that helps, (;-) TP

Offline Hood

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Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #2 on: August 10, 2009, 05:30:25 PM »
Depends, tapers are all the same but flanges are different. This will probably not matter to you unless you have a toolchanger then you will likely have to get the ones to suit. The CAT will need you to either modify one of the dogs or remove one as the slots are uneven in size on the holder.
 If you have the Bristol Erickson QC that is common on Bridgeport CNC's then you will need QC30 holders and that is all you will be able to use as their flange dia is 48mm as opposed to the 50mm of the others.
Hood
Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #3 on: August 10, 2009, 07:21:59 PM »
Ok, so if I understand correctly...  They can be interchanged, sort of.  The tapers are the same, NMTB has a short cylindrical section, the others don't.  The main difference will be in the height of the pull stud, and how the flange keys to the spindle?  I don't know for sure which taper the spindle I'm looking at has, but I'm guessing it's NMTB, which appears to be the most common, right?

Regards,
Ray L.
Regards,
Ray L.

Offline Hood

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Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #4 on: August 10, 2009, 07:34:46 PM »
Not sure what NMTB is, think it might be what we call international, ie just a single thickness flange of 8mm thick and 50mm dia. They  have the extended straight portion on the top of the taper but you can make up pullstuds for CAT, BT etc that will allow you to use them with the same drawbar as the INT (NMTB) I did that for the Beaver mill, it can take Int40, DIN40 (similar to CAT 40 but metric) BT etc
Top right is for Int40 left is the one I made up for DIN(CAT). The bottom one is for a Hurco 30 taper I made a load of for Brett.


Hood.

Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #5 on: August 10, 2009, 07:46:59 PM »
Hood,

Sounds right.  Here's the reference I found on all the different tapers:

http://www.tools-n-gizmos.com/specs/Tapers.html

Any clue what pullstud tension these want?

Regards,
Ray L.
Regards,
Ray L.

Offline Hood

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Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #6 on: August 10, 2009, 07:52:22 PM »
Afraid not, all I know is the hydraulic pressure  of the Beavers drawbar is 900PSI and the cylinder is about 60mm ID but not certain on that.

Hood
Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #7 on: August 10, 2009, 08:14:04 PM »
Afraid not, all I know is the hydraulic pressure  of the Beavers drawbar is 900PSI and the cylinder is about 60mm ID but not certain on that.

Hood

Hood,

Do you know how much travel is required to release the tool?

Regards,
Ray L.
Regards,
Ray L.

vmax549

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Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #8 on: August 10, 2009, 09:18:39 PM »
Tha would be about 3300 lbs on the rod side of the cylinder.

  The only spindles I have seen on common knee mills are R8, NMTB30/40, ISO30/40, Kwikswitch200/300, Erickson QC30 and a few Morse tapers.

The nature of the spindle drive/quill /High/low gearbox normally prevents the others from being used.

(;-) TP

Offline simpson36

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Re: CAT30 vs BT30 vs NMTB30 vs ????
« Reply #9 on: August 13, 2009, 03:09:52 AM »
Isn't the pressure mentioned used for releasing the drawbar?

Seems to me that the release pressure would need to be adequate for breaking loose the taper and could be many times the actual drawbar tension.