Help Needed ! I broke my SB vertical mill (1958)

Something broke inside my old SB mill. I am in hopes someone can direct me to some help (a parts diagram, a schematic, a break down sheet) or advice. Basically a small pin on the left side of the head fell out yesterday while using an end mill. It is located directly below a large round plate (approx. 2-1/2" diameter). See pics. And the ram fell straight down to the table ! It wont raise and it wont adjust up/down. Couple of questions 1) How does it come apart to get to this part ? 2) How serious of an issue is this 3) where on earth do I get a replacement part once it is identified ?

Thanks in advance.

dusty

My guess is your quill counterbalance spring let go. Either it broke or the pin anchoring it broke. As for parts, your odds are not much better than PowerBall. You'll have to make parts or have them made. I imagine a parts diagram is available on some Yahoo group or OWWM, but I've never had one of those mills, so never tried to look. OK here it is. It should be a simple assembly that you can figure out yourself. Just proceed carefully and don't resort to big hammers, pry bars, or pullers unless you know for sure they're needed. I hope you didn't damage the spindle bearings with a hard knock when the quill dropped. Did you not have the quill locked while you were using the end mill? You should have.

Yep- that little pin thing that fell out is the anchor for one end of the quill clock-spring.

It sounds like the spring may have broken, but you will have to take it apart and look. I had mine apart long ago to replace the woodruff key that was sheared off by a PO; but don't remember the details. If the spring is intact, you may just have to rewind it, and perhaps make a new pin or figure out why the old one is not staying in place.

It is part #28 on page 9; Rklopps link.

And the ram fell straight down to the table !

Click to expand...

That would have been exciting!. I think you mean the quill dropped. The ram looks to still be in place in the column.

smt

As to why the quill now won't go up or down, the drop might have caused quill elevation (rack) pinion to jam on the quill's rack. You might have to jiggle around with you hand on the quill and the feed lever. The spring counterbalances the quill, but it should move even without the spring engaged.

You'll have more knowledge more about your mill when you get this sorted out.

John

In addition to above, be careful when you remove the cover,the clock spring has a fair amount of energy in it and can come out with enough force to do you damage. Jim

If you can put a block of wood under the quill to support it, it may be possible to gently wiggle and gradually work it back up into contact with the rack gear while jiggling the handle. Be sure the clutch is set for lever feed, not sensitive (small handwheel) feed.

Don't try to force it up with the knee, if you can't wiggle it and move it more or less loosely by hand.

Yours does not have power feed on the quill, so it is unlikely that the woodruff key sheared. But if you were milling without the quill being locked, over time there is that possibility.

If the key is sheared, rotating the quill feed lever will not move the quill up or down, but it the lever should rotate more or less freely, depending how the key sheared and if it jambed in the rack feed gear. The worst part of that job is rewinding the clockspring. If I had to have it apart for that task anyway, I would go through the parts and make sure the keys and gears were in good shape and clean and lube them.

smt

All of that weight and length from collet chuck, and drill chuck beyond that....

Overhang causes deflection. Weight is hard on quill spring. Overwinding quill spring to haul that load up, shortens spring life.

BP mills have quill spring for balance only. Not a full blown drill press style return spring. It prevents sudden drop to table, but still allows good feel when drilling very small holes.

I know tooling is somewhat of a pain on a SB mill. But get a proper drill chuck arbor, enjoy 3 more inches of work space, from spindle to vise/table. Modify one of these by milling the 2 setscrew notches.. Machine Arbor NMTB 30 to 3JT Hardened Jacobs Taper Mount JT3 | eBay

Sometimes a new hole can be cut in quill return spring for anchor to catch. A Dremal tool with a carbide burr goes right through the spring steel.

Timesavers.com has clocksprings that may fit, with some alteration..

I have some South Bend mill parts, more than anybody on earth (that's not say much)
Email me your needs.
Ted
[email protected]

Thanks everyone for the help and suggestions. I don't think any damage occurred when the quill came loose. What is the next step to disassembly of this beast ??? where does one start so to speak. I have never had it apart but am not afraid to learn. Thanks dusty.

Start with a parts diagram so that you can figure out how to take it apart without breaking something else.

So......It appears from everyones' advice that my quill counterbalance spring pin broke ? Im attaching a photo for further direction. I can see that there is a pin holding the center of the spring in place and that pin seems to slide in and almost out of its hole position. When I turn the dial to raise / lower the quill the spring tightens up and just keeps spinning around. Nothing seems to hold the outer end of the spring in place and I presume this is what the broken part/pin did ? Has anyone taken this spring out ? and does it have a hold in the tail end of it to keep it from spinning under pressure ? (Hope this makes some sort of sense). Thanks does anyone have a parts diagram ? dusty

Just reach in there with a pair of needle nose, grab the inner end of the spring and take the spring out. You'll
probably need to finagle it a bit to get it over the pin. Then to remove the spring, keeping the grip in about the
same place, wind the inside of the spring clockwise while you take it out. Sorta screw it out clockwise. Keep
your other hand ready to capture the spring while it comes out of the bore. When it's out you can slowly let the
spring relax in the hand that's holding it.

Now all should be clear. Self explanatory from there. And there's nothing special about the broken pin. Just
look at the pin and the hole in the spring to see how it was. Make a new pin (nails work).

Pete