South Bend Mill tool holders

[alanganes]

Alan & Fasttrack
As you can see in the photos, I have added a "poor man's DRO" to my mill. The system works great for me. Enjoy the photos
BMSS

Looks good! Nothing wrong with your poor man's DRO. A while back I scored an almost free, old but functional 2 axis Anilam DRO and scales for my machine. Sounds silly, but it was like getting a new mill. Just soooo much easier to use, no more counting turns, and forgetting to approach from the "correct" direction. It is a very basic DRO, no fancy offsets or bolt circle calculations but I would hate to be without it now. Spoiled, I guess.

It is almost more like the drive dogs serve as the retention system
It has typical looking drive dogs, but each has an angled hole in it, that is threaded for a set screw that protrudes into the spindle and presses against the flats on the tapered tool holder. The dogs do the driving, the screws basically push the holder into the taper. Sort of a backwards, upside-down drawbar. Like I said, works fine, just not real fast.

I'll try to get a few more pictures up later on in the weekend.
Thanks for posting those.

-Al A.

[Fasttrack]

Thanks for the pics! Thats a neat little mill.

[tiptop]

BMSS,

I guess I should have been wearing glass' before making my statement. So the retention system also serves as drive dogs? Good to hear that, I was having a hard time thinking S.B. came up with a system that did not incorporate them.

Jay

[BMSS]

Actually Tiptop, the system works very well, and you do have a set of drive dogs that engage the toolholder. The holding bolts actually thread right through the center of the dogs. I should have gotten a better picture of it, I guess.

[tiptop]

The tool holders look just like a modified NMTB 30 taper tool holder. I suppose it would work alright as you all have stated that it does. It is unfortunate that you are not able to have a set of drive dogs in the tool holder slots which look to me to be hidden from the quill by the attachment system. This is one of the nice things about NMTB series holders, you not only have a very large taper contact area but the drive dogs also. Then as I am sure you are aware of it being a faster tool change with a draw bar or draw bolt. It is to bad they did not put a hole through the motor spindle for a long allen wrench to tighten a draw bolt. That is kind of what they did on the Frays. Th S.B. millers are nice looking HSM machines, just a little smaller that my Fray on travels.

Jay

[BMSS]

Alan & Fasttrack
Sorry it has taken me awhile to get back to my post. I had to go out and take some pictures. I can't post here, but you can see my mill at;

http://s552.photobucket.com/albums/jj353/BMSS_photos/Mill%20tool%20holders/

As you can see in the photos, I have added a "poor man's DRO" to my mill. The system works great for me. Enjoy the photos

BMSS

[alanganes]

It is a bit strange, and after having one for a while, it's obvious why this system never caught on. It works well enough though, I've never had a hint of anything working loose. Just a bit of pressure on the screws seats the tool in there very securely, I guess due to the large taper contact area.

Not real fast for tool changes, but I mostly use the collet holder anyhow, and have all of the collets that it originally came with. And I'm not in much of a hurry.

Perhaps it is the presence of those two pockets that makes this a "milling machine" taper rather than an NMTB. It seems to be identical otherwise. I have never see one used on any other machine, but I don't get out much, either.

Here is a picture of mine:



Not a great view for what we are discussing here, but you can almost see that the motor is mounted directly above the quill. The motor is only about 6" high. These mills used a Fairbanks-Morse or GE "pancake" motor, which is very short and fat compared to modern motors. It was available with either a 3/4 HP or 1 HP motor, and either could be ordered in single or 3 phase. Mine is the 3PH, 1HP unit, I run it with a VFD.

All in all it is a decent mill for my purposes.

I can get a few better angles if anyone cares to see.

[tiptop]

It looks like a strange way of securing a 30 taper. One thing that comes to mind is without the same torque on your retention screws, it will work in the taper. The NMTB tapers are far superior to R8 tapers, this can be seen in the contact area of the taper. They are very rigid they can be found in 20, 25, 30, 35, 40, 50 and 60 series. I would also like to see a picture of your mill. I have looked at them in the past but don't remember them not having a drawbar. Old age is great. There is a lot of used NMTB stuff out there, but NMTB 40 and NMTB 50 seem to be the most common as this was most prevelant in industry. I run NMTB 30 in my mill with a drawbar and am very happy with it.

Jay

[Fasttrack]

I'd like to see some pics of the mill, if you've got the time. I'm amassing a collection of mill photographs. Sort of like my own, personal version of Tony's Lathes.co.uk site.

[pcarpenter]

Your photo seems to show some holders I have seen before...and never understood. I do now. Other than the grooves ground in for retention, the holders look like the 30 national holders I have. With that in mind, it really is possible that the reason they look hand ground is that someone took a standard holder and put the retention grooves in it with an angle grinder or something. They sure are deep!

In any case, I will bet that will point you in the right direction. There should be some used 30 National (NMTB) stuff out there and I know you can get some import items as well although the 40 National is more common.

Paul

[oldtiffie]

NMTP tapers

Paul,

these pics/scans should help in regard to the NMTP tapers - including 30:

http://i200.photobucket.com/albums/aa294/oldtiffie/machine_tapers/Machine-taper5.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Machinery_HB27/NMTP_tapers1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Machinery_HB27/NMTP_tapers2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Machinery_HB27/NMTP_tapers3.jpg

[BMSS]

Alan, I would like to have a scanned copy of that manual.
You can e-mail it to me at;
[email protected]

Again, Thanks for all the help.

Bob Denton

[alanganes]

You are most welcome. Glad I can help out.

If you would like a copy of the manual, I found my scanned copy. It is a quite large, 3 PDF's, about 6megs each. I can email them, or find someplace to post them for download. They are good clear scans that I did myself from my manual and parts list.

Enjoy the mill, I like mine!

-Al A.

[BMSS]

Thanks Alan, that answers all my questions. I appreciate the help.

Bob Denton

[alanganes]

No, they came that way from the factory and they are shown as such in the original manuals. They never had a drawbar setup, as the motor sat directly above the quill.
Mine has the original pancake motor, I run it off of a VFD. My spindle is set up the same as your, with the 2 set screws. Your toolholders look to have been modified from standard units.

Late addition:

I just found the link to this post from PM that I had saved. It should answer some of your questions with respect to the toolholders, and shows how one guy modified some modern units for use on this machine:

http://www.practicalmachinist.com/vb/showthread.php?t=153209&highlight=ER40+collet+chuck

-Al A.