South Bend Mill

[arizonian]

The mill I have is on old South Bend knee mill. I don't know the history other than it is the same mill that I used in the high school machine shop class, still has the Amphitheater HS tag, and we bought it from the winning auction bidder a few years later. That was over 35 years ago.

The tool attachment point is a South Bend propriatory collet arrangement. Collet sizes are 1/4, 3/8, 1/2, 5/8 and 3/4". There is no thru hole in the quill and there is no room anyway. The motor drives the quill thru a double set of pulleys and sits right over the quill.

I have had a tool slip in the collet once so I backed off the DOC and continued.

Does anybody out there have any experience with this mill? Any way to improve the tool holding capability of this mill?

[Shade Tree Welder]

You say quill I think you mean spindle. The quill is what moves the spindle up and down.

What is the tool holder, a 30 taper or is that custom too?

I would suggest getting a new tool holder that takes an ER series of collets.
There are different OD dimensions of ER collets, but that will get you into
a standard set of collets and some a proprietary nightmare.

[arizonian]

I have not checked the taper, but it looks like 30° from my living room.

Are alternate tool holders available? From where?

[LKeithR]

Originally Posted by arizonian

I have not checked the taper, but it looks like 30° from my living room.

Are alternate tool holders available? From where?

Thirty degrees and 30 Taper are two different things. I have no experience with that mill so I'm wondering if the collet holder itself is removable? If that's the case then you can remove it and try and identify the taper.

I have a collet setup for my mill but I generally prefer to use endmill holders. They lock solidly onto the endmill shank so there's no problem with slippage and, because of the way they stick out you get a little more clearance around the endmill.

This website has good information on most of the machine tapers out there...

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

[arizonian]

To answer both questions, it is a #30 Steep Machine Taper per Machinery's Handbook #25, 3.500" per foot, 1.25" at the big end and 1.875" length.

There is no drawbolt to retain the collet body, only the two canted indentations on the side of the taper with a pair of socket head set screws doing the work.

One edit, found this video.

Link

[arizonian]

Two years have passed and now I have another question.

When I built the windmill I did all the boring on the mill with the handwheel. With all the recent work on the lathe complete, I figured it's time to get the hydraulic downfeed working. There is oil in the pump, the pump does run and is rotating the correct direction, not so sure what kind of pressure it puts out.

When turning the dial for downfeed, the black knob to the left turns 1 rotation and stops. Turning for upfeed, the knob rotates the opposite direction. The knob does not go in or out. The quill does not move with the hydraulics, only the handwheel and handle.

[greywynd]

Never dealt with one of those. First thing I think I would do, is see if you can get a tee in there somewhere with a gauge to check for pressure. Also, is it a 3 phase pump motor? Any chance it’s running in reverse?


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[arizonian]

Three phase as is the spindle motor. Checked rotation and it's going like it should according to the arrow on the pump.

[digr]

Is your mill? Looks like there are two bolts that lock the 30 taper in the quill

[arizonian]

That's my mill, Southbend MIL 4218. Thanks, Digr.