Recommendations for a chuck with NMTB 50 backplate?

gi_984 · Apr 22, 2018

Good afternoon. I'm looking for a 3 or 4 jaw chuck with the NMTB 50 backplate to fit my VN dividing head (10 inch swing). Is there a source for NMTB 50 backplates so I can fit up one of my spare chucks? I've done some searching but nothing comes up. So leads would be appreciated.

I'd be open to buying an older 3 jaw or 4 jaw chuck already mounted on a NMTB 50 backplate. But I've never seen one. Did they use a shorter than standard drawbar to mount into the DH spindle?

Any particular brands that were better than others? Cushman, Buck, etc? Or were they branded K&T, Cincinnati, etc?

TIA

Illinoyance · Apr 22, 2018

VALENITE NMTB 5 SHELL MILL ADAPTER 2" ARBOR STK 16233 | eBay

Start with something like this. Make an intermediate plate that fits the facemill arbor. Machine the chuck register by using he dividing head to rotate he adapter plate while milling the register. Mount any flat back chuck of your choice.

Edit
Now that I have seen the photos of the dividing head, a shell mill adapter is not needed. The adapter plate can locate on the OD of he spindle and be held by bolts in the existing tapped holes.

thermite · Apr 22, 2018

gi_984 said:
Good afternoon. I'm looking for a 3 or 4 jaw chuck with the NMTB 50 backplate to fit my VN dividing head (10 inch swing). Is there a source for NMTB 50 backplates so I can fit up one of my spare chucks? I've done some searching but nothing comes up. So leads would be appreciated.

I'd be open to buying an older 3 jaw or 4 jaw chuck already mounted on a NMTB 50 backplate. But I've never seen one. Did they use a shorter than standard drawbar to mount into the DH spindle?

Any particular brands that were better than others? Cushman, Buck, etc? Or were they branded K&T, Cincinnati, etc?

TIA

I'm not personally familiar with VN DH, but most DH had BOTH an internal taper and a threaded spindle.

Chucks, if/as/when wanted (eg: Not all the time) are more easily mounted to the spindle rather than off whatever the taper is. Ordinarily, it is one also common to one or more lathe clans.

Other goods might be more easily mounted using the ID taper. That is ordinarily common to one or more milling-machine or drillpress tribes.

Mounting either of those "classes" of goods the other way 'round gets costly, inconvenient, or both.

gi_984 · Apr 22, 2018

Illinoyance, thanks for the suggestion. But I'd rather find the proper backplate if possible.

thermite, I've attached a picture of my DH. Got it covered in storage grease. Came with the tailstock, draw tube, collet insert (takes VN 2 collets), and one dead center. The plate in the foreground of the picture is an unknown.

Thoughts?

Dang picture keeps attaching upside down!

Dan from Oakland · Apr 22, 2018

Not trying to sell stuff here, but I do have several 50 NMTB shell mill arbors for fairly large bore shell mills that are available. You could easily press a flange on one of these and mount a plain back chuck. Only issue you wont have a thru hole. My VN dividing head has a flat back Skinner 3 jaw on it but it does not utilize the taper- it mounts with 4 thru bolts in to the flange around the outside of the 50 taper. The chuck has a straight counterbore that fits over the OD of the dividing head spindle. Pretty easy to make a back plate that mounts the same way. I have the same dividing head shown in the picture above- notice the threaded holes in the spindle face and how the collet nose mounts- same idea for a chuck.

thermite · Apr 22, 2018

gi_984 said:
View attachment 226605

Illinoyance, thanks for the suggestion. But I'd rather find the proper backplate if possible.

thermite, I've attached a picture of my DH. Got it covered in storage grease. Came with the tailstock, draw tube, collet insert (takes VN 2 collets), and one dead center. The plate in the foreground of the picture is an unknown.

Thoughts?

Dang picture keeps attaching upside down!

I'm a Horizontal mill hand. There is no such thing as "upside down".

I'd say you are in LUCK!

Looks as if what VN did was take advantage of their threaded holes in the face of the spindle to fab various mounting plates that were retained with capscrews and needed only a short stub of 50-taper shape for precise centering. No need of the mass, storage and handling awkwardness of the whole full-length 50-taper body.

The effect is like an A2 lathe spindle nose with the cone reversed, inward rather than outward.

Duplicate that stub 50-taper as those plates use for your chuck backplate, pick up on at least one tab or hole for indexing. Use a stub drawbar 'coz you can't get AT the bolt circle through the body of a 3-J scroll from the front, and you should be able to mount and de-mount a scroll chuck.

If you need a clear bore, use a 4-Jaw independent chuck, no scroll plate, and you can bolt it from the front, no drawbar needed.

There may be a better way or three if you can find old VN catalogs and see what they offered, store-bought.

Meanwhile, it seems the evidence in your hand shows "a" way, if not "the best" way.

Danny VanVoorn · Apr 22, 2018

I'd machine a simple plate thick enough for recessed cap screws to use the holes in the spindle and allow for a snug fitting recess to match the OD on the spindle. Machine the other side to match the chuck of your choice and bolt it on last. Might be able to machine one plate to use multiple chucks depending on the planning? A 50 Taper adapter might be easier/faster to mount but you won't be able to use the through hole with one either. About 6 of one and half dozen of the others?
Dan

Mud · Apr 22, 2018

50 taper centering plugs are available. 2" seems most commomn, I've seen 2.5" and have a 1.875". I also have a 50 taper arbor that has a full diameter flange with the bolt pattern of the spindle in it, weighs about 60 lbs, but that seems redundant.

USED LOVEJOY TOOL NMTB 5 x 2." TAPER CENTERING PLUG NMTB5 (5STP8) | eBay

thermite · Apr 22, 2018

Mud said:
50 taper centering plugs are available.

Quite a few 50 taper face mill arbours out there with "some" useful meat on them for the butchering as well, around $60 and up. Heavy, bulky, awkward. But cheap and fast.

That was my go-to for the #9 B&S on the wee Ellis DH I have until I could find one of the not proprietary, but nonetheless "minority use" threaded backplates for it.

The small Ellis DH entire is close to the mass of but one 50-taper item, so.. all depends on how much force one has to ask it to manage. And whether it is geared to sync, of course. Mine ain't.

gi_984 · Apr 22, 2018

Thanks for the replies. Making more sense to me. Thing is covered in preservative grease (cosmoline). Got the big stuff off. Need to give it a good brush down with kerosene. So there is still some plus staining that shows in the pictures. You can see how this adapter plate fits the 50 taper and has the holes to bolt it to the face of the DH. Then the dead center inserted with the draw tube pulling it in from the rear. Last is some kind of drive plate. So I can at least turn between centers right now with the tailstock.

gi_984 · Apr 22, 2018

Those are all good suggestions. Lot simpler than what I was thinking originally.

Dan from Oakland: I'd be interested in seeing some pictures of your chuck and mounting plate. Send me a message. I'm in the market for a NMTB 50 shell mill arbor.
Need some NMTB 30 tool holders, etc for a vertical mill head attachment.

I did pull out my old copy of the VN accessories catalog from mid 1950's. They describe 3 and 4 jaw chucks that use a mounting plate. But no pictures of these. Perhaps the adapter plate I have is what they were describing it the catalog? Certainly sounds like a solid way to mount a chuck per everyone's suggestions.

Anybody else have pictures of a chuck set up like this?

TIA

thermite · Apr 22, 2018

gi_984 said:
Last is some kind of drive plate. So I can at least turn between centers right now with the tailstock.

Yup. And not only.

As said - a "chuck" is not always wanted for the work a DH is asked to play with anyway.

Apply some faceplate-tooling philosophy foo, and one can often save time, money, and daylight by ginning up something with a bit of scrap plate and common fasteners.

gi_984 · Apr 23, 2018

I suspect I can turn up a mounting ring like Danny Vanvoorn suggested easier than finding an original factory one. Then I could use a 4 jaw independent like thermite suggests.

"Apply some faceplate-tooling philosophy foo, and one can often save time, money, and daylight by ginning up something with a bit of scrap plate and common fasteners."
That is a great idea! Will do.

Miguels244 · Apr 23, 2018

FYI, grizzly sells a cast iron ring fo66 bucks as a blank back plate.

johnoder · Apr 24, 2018

In case not known

Fifty taper 5.0625 OD is concentric to taper

Fifty taper face is square to spindle C/L

Fifty taper has four 5/8-11 tapped holes

This adapter locates on OD and attaches via the THREE tapped holes on this 12" K&T Model K dividing head

The "home brew" adjust tru is just part of the story

Replacement photos near end of thread in Post #12 (I was unaware PB made their notices giant sized

)

http://www.practicalmachinist.com/vb/general-archive/shop-built-adjust-true-86789/

gi_984 · Apr 24, 2018

johnoder,

Very nice work. I think I will do something similar with one of my 4 jaw chucks.

Thanks for the link to the original post. Too bad the other pictures and link to the pdf's don't work anymore.

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Recommendations for a chuck with NMTB 50 backplate?

gi_984

Aluminum

Illinoyance

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thermite

Diamond

gi_984

Aluminum

Dan from Oakland

Titanium

thermite

Diamond

Danny VanVoorn

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Mud

Diamond

thermite

Diamond

gi_984

Aluminum

gi_984

Aluminum

thermite

Diamond

gi_984

Aluminum

Miguels244

Diamond

johnoder

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gi_984

Aluminum

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