Using CAT holders in NMTB spindles

Cannonmn · Sep 25, 2020

I’ve got some really nice CAT-40 tool holders Id like to use in my Enshu Accumill, which has an NMTB 40 spindle with two removable keys on spindle lower face. I know some ppl remove one key to accommodate the half-depth notch on one side of their CAT holder, hopefully for less severe torque cutting. Is there any other method or adapter for using CAT-40 holders in NMTB spindles?

Pic of one of my CAT 40 holders:

Flickr: Page Not Found

BTW just noticed some unknown arbors show you on edge of the photo, does anyone know what they are for? Think I have better image if needed.

thermite · Sep 25, 2020

Cannonmn said:
I’ve got some really nice CAT-40 tool holders Id like to use in my Enshu Accumill, which has an NMTB 40 spindle with two removable keys on spindle lower face. I know some ppl remove one key to accommodate the half-depth notch on one side of their CAT holder, hopefully for less severe torque cutting. Is there any other method or adapter for using CAT-40 holders in NMTB spindles?

Pic of one of my CAT 40 holders:

Flickr: Page Not Found

BTW just noticed some unknown arbors show you on edge of the photo, does anyone know what they are for? Think I have better image if needed.

Torque is not enough less on a CAT 40 to matter. Both lugs do not necessarily even come into full contact. Most CAT goods saw HEAVIER service on newer spindles than the earlier NMTB 40-Taper goods did on older, often lower-powered, machines.

Primary drivers of the newer variants was to make them automated toolchanger and toolholder "magazine" frendly, pull-stud / power draw-up compatible, including goes-in at one orientation only, not either of two positions.

One can remove a lug, alter one, alter both, depending on what your needs and environment call for. Drawbar length if not also thread is the other thing that may need seen to.

All-manual here, so I'm set up with NMT 40 and CAT 40 interchangeable, but avoid mixing in BT.

Arbors you asked about could be B&S Taper if not MT?

Cannonmn · Sep 25, 2020

Thx I’ll have to look up what a BT arbor is.

Another question, related: Came across some newish arbors that seem to match NMBT40 in every way but are neckless. Univ eng make. Can post pic if needed. Wat r dose fur?

thermite · Sep 25, 2020

Cannonmn said:
Thx I’ll have to look up what a BT arbor is.

Another question, related: Came across some newish arbors that seem to match NMBT40 in every way but are neckless. Univ eng make. Can post pic if needed. Wat r dose fur?

"BT" is a metrifuckated NMTB descendant. Ericsson had another one.

One CAN use these in other 40-taper spindles. They are just more of a nuisance if you were inch drawbar rather than metric at the outset. Or the reverse where the machine was metric to begin with.

What you do NOT want to do is mix any of these families in a CNC'ed magazine/toolchanger/power pull-stud drawbar environment. Pick any one. Stick with it, rather.

B&S is Brown & Sharpe.

As Morse taper is to linear-loaded drilling, B&W taper was to (also) side-loaded milling. Angle of the taper is JUST enough different that:

- a B&S taper drill (they existed) is prone to sticking in the socket, Morse not so much.

- a Morse taper used for milling is prone to walking out, B&S not so much.

Horses for courses.

Post a photo. "neckless" is a genetic anomaly.. Universal Engieering did some neat things with Quick Change / Quick Switch systems, and "not only".. never mind. Show us.

Cannonmn · Sep 25, 2020

Feelthy peeksures

John Morris has shared 3 photos with you! | Flickr

1 Jaw Chuck (Chuck Evans) · Sep 25, 2020

John,

My K-T is NMTB 50. It is my only machine that takes NMTB 50, so what I did to my CAT 50 holders was to mill the smaller slot to the same size as the wider slot.

Now all my holders are plug and play, no stopping to remove the lug or
wondering why the holder won't go in.

Those 3 photos look like CAT 40. Whats the thread size?

Chuck
Burbank, CA

thermite · Sep 25, 2020

Cannonmn said:
Feelthy peeksures

John Morris has shared 3 photos with you! | Flickr

Aha! Not "neck" to me. Bass-ackwards.

The straight-cylindrical reduced-diameter tail section is at the ARSE end - what you meant was missing.

Grab yerself a copy of the info comparing NMTB, CAT, BT, Ericsson, and the more popular of the rapid-swap "Quick' this-and that, and the self-retaining or front-flange-retained (Deckel has used that system..) rather than drawbar / pull-stud proprietary goods, etc.

It will make it easier to ID and peddle what you have inherited and do NOT need, as well as reduce shopping risk when scouting for what you DO need.

Many of us are grateful for this one, but there are more sources of the info you will eventually need as well:

Machine Tool Shanks (Tapers)

Cannonmn · Sep 25, 2020

Chuck Evans said:
John,

My K-T is NMTB 50. It is my only machine that takes NMTB 50, so what I did to my CAT 50 holders was to mill the smaller slot to the same size as the wider slot.

Now all my holders are plug and play, no stopping to remove the lug or
wondering why the holder won't go in.

Those 3 photos look like CAT 40. Whats the thread size?

Chuck
Burbank, CA

Neck threading is

5/8-11

1 Jaw Chuck (Chuck Evans) · Sep 25, 2020

John,

Sounds like CAT 40 to me.

Do go to thermite's link: Machine Tool Shanks (Tapers)

Good source of information.

Chuck
Burbank, CA

Cannonmn said:
Neck threading is

5/8-11

Cannonmn · Sep 25, 2020

Chuck Evans said:
John,

My K-T is NMTB 50. It is my only machine that takes NMTB 50, so what I did to my CAT 50 holders was to mill the smaller slot to the same size as the wider slot.

Now all my holders are plug and play, no stopping to remove the lug or
wondering why the holder won't go in.

Those 3 photos look like CAT 40. Whats the thread size?

Chuck
Burbank, CA

Thx Chuck, I have a lot of NMTB 50’s also, for the larger mills, one of which is a K&T Vertical probably same as yours. I’ve also acquired a dozen or more CAT-50 holders. I thought it was sacreligious or something to modify them but now I can explain to my conscience “well Chuck does it” and cut into any where I need that particular configuration. Thanks!

thermite · Sep 25, 2020

Cannonmn said:
Thx Chuck, I have a lot of NMTB 50’s also, for the larger mills, one of which is a K&T Vertical probably same as yours. I’ve also acquired a dozen or more CAT-50 holders. I thought it was sacreligious or something to modify them but now I can explain to my conscience “well Chuck does it” and cut into any where I need that particular configuration. Thanks!

Yahbut... modify the lug and it is do once per each SPINDLE.

Modify the holder, it is ALL of them of the type, One, two, or twenty-two..

Not about "sacrilege". Less time. Less work.

Especially as lugs can be replaced easily. wear and damage was expected, one spindle, many holders.

Ever you change your mind or sell the machine, no lasting harm. Not an "orphan".

Material milled away? Not so easily reversed. Frankenorphans, permanent-like.

MetalCarnage · Sep 25, 2020

Would something like this work for you?

DZ Sales CAT40 to ISO40 Adapter | eBay

-Ron

Cannonmn · Sep 25, 2020

Thanks Ron! Damn if that isn’t one of my missing necks! Some lowlife stole ‘em, repainted ‘em, and now has the NERVE to sell ‘em thinkin’ I won’t reckanahz ‘em!

But who’s gonna believe me? I guess I jes’ oughta buy some of ‘em back.

Well of course I have to see how they are threaded, the ad says one end is 5/8-16 and I think I need 5/8-11.

LKeithR · Sep 25, 2020

I've posted this before but here it comes again. Lots of info on machine tapers...

Machine Tool Shanks (Tapers)

thermite · Sep 25, 2020

Cannonmn said:
Thanks Ron! Damn if that isn’t one of my missing necks! Some lowlife stole ‘em, repainted ‘em, and now has the NERVE to sell ‘em thinkin’ I won’t reckanahz ‘em!

But who’s gonna believe me? I guess I jes’ oughta buy some of ‘em back.

Well of course I have to see how they are threaded, the ad says one end is 5/8-16 and I think I need 5/8-11.

Black oxide ones are cheaper. I inherited two different drawbars. Then realized I didn't exactly have a "spare". PO had onpassed more than one type of holder!

OTOH, that colour band exists for good reason. So yah don't mix ones that ain't the same.

PS: Same sources as have these may also stock screw-in TANGS for Morse-taper goods with drawbar threads. I keep a couple of each size stashed.

Given that Lybarger's Corollary applies to all things, I'll not be able to find them, ever I actually NEED them, but even so?

Anything like that yah put-by pretty well insures you will never need it!
Teats on a Boar Hog Corollary, izzat? If nothing else, they do seem to prevent a backfire getting the Boar pregnant.

Cannonmn · Sep 26, 2020

Here’s an idea for making new necks for my neckless CAT40’s so the arbor’s threads are in the right place for the Cnc’s power drawbar. If this were for a manual-drawbar machine, yes I’d just make an inch-longer drawbar and switch to it when using neckless CATs. But don’t want to go there with the CNC, impractical. So thinking of using one-inch lengths of 5/8-11 couplings and a short length of matching althread. https://www.mscdirect.com/product/details/51258309

Then I’ll have 1/2” of the coupling for the drawbar to grab and 1/2” of it for the althread that threads down into the CAT arbor. I’ll just turn off the points of the hex coupling that extend outside the 0.9xx spindle I.d. required for clearance of nmtb 40 necks. Yes this CNC has nmtb40 spindle.

So is my planned 1/2” threaded contact way too little or no problem? There will be 5 1/2 threads in contact (11 th/in. x 0.5 in.) = 5.5 threads

thermite · Sep 26, 2020

Cannonmn said:
Here’s an idea for making new necks for my neckless CAT40’s so the arbor’s threads are in the right place for the Cnc’s power drawbar. If this were for a manual-drawbar machine, yes I’d just make an inch-longer drawbar and switch to it when using neckless CATs. But don’t want to go there with the CNC, impractical. So thinking of using one-inch lengths of 5/8-11 couplings and a short length of matching althread. https://www.mscdirect.com/product/details/51258309

Then I’ll have 1/2” of the coupling for the drawbar to grab and 1/2” of it for the althread that threads down into the CAT arbor. I’ll just turn off the points of the hex coupling that extend outside the 0.9xx spindle I.d. required for clearance of nmtb 40 necks. Yes this CNC has nmtb40 spindle.

So is my planned 1/2” threaded contact way too little or no problem? There will be 5 1/2 threads in contact (11 th/in. x 0.5 in.) = 5.5 threads

You have a machine shop. You CAN make an adapter to a Rudge-Whitworth wire wheel knock-off hub nut if it rocks yer boat.

But this makes no sense to me.

The 'bobtail' 40 taper fit somebody else's spindle just as they are.

Best to peddle them, as-is. Problem one solved. YOUR misfits become some other Pilgrim's active-dury useful goods. As-is.

How many do you have, anyway? Are they Quick-Switch? Or what?

Regardless... shed them.

No need to wait..

Go and acquire whichever and whatever variants of 40-taper goods as already fit YOUR spindle that you actually NEED. If-even you need any.

By trade or purchase, new, used, or some combination thereof.

Less work.

Less time wasted.

Less risk of a kludge going pear-shaped.

Why mess?

Cannonmn · Sep 26, 2020

I’ll fur sure make one and try it out. Maybe I’ll just save these ordinary CAT 40 arbors for the manual K&T vertical mill (nmtb50 spindle) that’s easy to switch drawbars. I keep a 50-40 arbor adapter with it, has machined-in keys but I could just cut one off .

wesg · Sep 27, 2020

You might want to make sure you can get the adapter out if it decides it likes the drawbar better than the toolholder. One piece, or loctite the stud in the coupler, and mill a hex on the end so you can reach up there with a socket.

Cannonmn · Sep 27, 2020

Thx, I’ll only do any of this if I can’t make do with about 40 nmtb-40 holders I keep by the CNC now, think I’m pretty well fixed but you never know. I haven’t run any nmtb—40 let alone CAT-40 holders using the adapter for the K&T’s nmtb50 spindle, but plan to try it if I ever get caught up.

Higher pri things now include fitting a DRO to the big OKK vertical mill, getting the 25-T. Di Acro brake fully adjusted, freeing and taper-grinding two nmtb50 arbors now attached to boring heads, finding why the Hardinge 2nd op lathe won’t run, and a few other things I won’t think of until I walk past them.

Using CAT holders in NMTB spindles

Stainless

Diamond

Stainless

Diamond

Stainless

Cast Iron

Diamond

Stainless

Cast Iron

Stainless

Diamond

Stainless

Stainless

Stainless

Diamond

Stainless

Diamond

Stainless

Titanium

Stainless

Similar threads