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tony ennis
11-15-2007, 12:10 AM
After must anguish and gnashing of teeth, I have all the doodads off my Atlas spindle. Well, except for the faceplate but that's something I'll address later.

Q1: The bull gear and pulley are scored where they rub at their hubs. Because the bull gear's lock pin must engage the pulley, I can't separate them much at all. 1/16th would be about the limit. What material would be good for putting between two independently rotating parts?

Q2: Is the wide ring located by the spindle's nose threads supposed to ride against the outside of the right babbitt bearing? That doesn't sound like what that bearing is for.

Q3: What is that ring for?

Q4: If the answer to Q2 is "no, it doesn't ride against the babbitt" then what would keep the spindle from being pushed out the left side of the headstock? There is one setscrew that would prevent it, but I don't think that counts for much.

Q5: Is it common to have spindle showing in the headstock, or am I missing another collar/shim/spacer? I am guestimating 5/16" of nothing will be between the bull hear and right babbitt.

Thanks!

SGW
11-15-2007, 08:04 AM
Do you have anything resembling a thrust bearing in the setup? That 5/16" gap sounds about right to accept a thrust bearing of some kind, although I'm not sure it would go where you say the space is.

On the South Bend 10K, there is a ball race thrust bearing on the left-hand end of the spindle. Of course there is no assurance, at all, that the Atlas would be set up the same way.

As far as your Q1, I'd vote for a hardened and ground shim washer, if it proves necessary to put something in there. I think www.reidtool.com may have them, 1/32" thick.

tony ennis
11-15-2007, 08:58 AM
Someone previously had put a 3/4" thick ball thrust bearing at the left end of the spindle, inside the casting. It was too thick, however, and caused the other innards to be shoved to the right. This made the back gear and bull gear not line up properly with the mating gears on the back gear shaft. So he modified the back gear shaft - badly. In fact part of the large back gear is chewed up from kissing that 3/4" bearing he stuck on the spindle. :mad:

I put a replacement back gear shaft on. This shows me where the gears should go on the spindle. I need about 9/16" of thrust bearing on the left side. This will allow all the gears to mate properly. Everything else on the spindle needs to touch. That means the spare ~3/8" must be at the far right end.

I am comforted in that I can not possibly leave this worse that it was when I found it. ;)

Hardened and ground shim washer - check. I didn't know it I should go steel, brass, or synthetic.

Upon reflection, I think I have answered Q4. A part is missing. I am betting a "flange bearing" is what is needed. The small end would butt up against the mysterious abbreviated steel sleeve, and the large end would be against the babbitt, or in my case, a ball thrust. Chances are when The Dude did his spindle mods, he used the only bearing he had and then discarded the flange bearing since it no longer fit. He then had trouble with the spindle sliding, so he cranked the setscrew in the bull gear down. You can tell it took him a few tries. The journals are ok, fortunately.

Carld
11-15-2007, 10:21 AM
Tony, have you done a web search for a pictoral diagram of your lathe headstock?

The Practical Machinist site has a forum page for lathe help. There should be a web site for Atlas lathes. I am sure there is a barrel full of info on the Atlas and all the others.

gzig5
11-15-2007, 10:44 AM
Tony, have you done a web search for a pictoral diagram of your lathe headstock?

The Practical Machinist site has a forum page for lathe help. There should be a web site for Atlas lathes. I am sure there is a barrel full of info on the Atlas and all the others.

http://www.atlas-press.com/servicebulletins.htm#12"%20Lathe%20Bulletins

Lots of good instructions and diagrams here..

tony ennis
11-15-2007, 10:47 AM
I have found Timken headstock diagrams but no Babbitt headstock diagrams. Of course, until a few days ago, I didn't know I needed it so I'll look specifically for it now.

And I realize that it doesn't matter too much how this goes together as long as all the important bits can be oiled and all metal-versus-metal contact points have bearings.

andy_b
11-15-2007, 12:30 PM
After must anguish and gnashing of teeth, I have all the doodads off my Atlas spindle. Well, except for the faceplate but that's something I'll address later.

Q1: The bull gear and pulley are scored where they rub at their hubs. Because the bull gear's lock pin must engage the pulley, I can't separate them much at all. 1/16th would be about the limit. What material would be good for putting between two independently rotating parts?


Thanks!

you can get all kinds of thicknesses of teflon sheet on fleabay. that may work, and won't be affected by any existing galling.

andy b.

Carld
11-15-2007, 12:46 PM
I'm with you Tony, the spindle shouldn't be thrusting against the babbit bearing. There should be a thrust bearing somewhere to keep the load off the babbit.

tony ennis
12-05-2007, 08:19 PM
To summarize several of my posts, I'm repairing my Craftsman's spindle. A previous owner had modified the left-end spindle area which took the thrust off the spindle and routed it through the bull gear's set screw, the bull gear, the cone pulley, the back gear, and finally to an enormous thrust ball bearing. When you consider that the cone pulley and back gear rotate freely on the spindle, and at a different RPM than the bull gear... Houston, we have a problem.

One thing I discovered about my spindle is that it's not like the others I've seen on the web. The steel shoulder on mine is fully 1/2" shorter than it should be. The shoulder is supposed to extend past the back gear so it can transfer thrust to the thrust bearing. But it doesn't. That, and the lack of a flange bearing, was why the headstock had that weird thrust path.

Here's the spindle. The part we're concerned with is the shoulder in the middle of the image. I have to get the force from that shoulder to the thrust bearing.

http://bp0.blogger.com/_Mv0bGRyF_LA/R1Sw5lzUjEI/AAAAAAAAAFU/0gqN6oErnIA/s400/spindle_shoulder.jpg

I ordered a remarkably thin needle thrust bearing and a sintered bronze flange bearing. My friend used his Sherline to part the flange bearing to length. In this picture you can see how the bronze bearing channels the thrust from the spindle shoulder to the thrust bearing.

http://bp1.blogger.com/_Mv0bGRyF_LA/R1N_gFzUjBI/AAAAAAAAAE8/AjurCutJ_a4/s400/rebuilt_spindle_2.jpg

The back gear isn't really secured now that I removed that huge bearing. Originally I was going to secure the gear to the cone pulley but I've nixed that. Instead I turned a UHMW retaining ring that consumes the empty space between the back gear and the thrust bearing. Here's the ring. Note how it rides on the flange bearing. The ring fits relatively loosely and, being UHMW is very slick. If all goes according to plan, the back gear will not be able to affect the bearing.

http://bp0.blogger.com/_Mv0bGRyF_LA/R1OAc1zUjCI/AAAAAAAAAFE/Ky37UalK0Is/s400/rebuilt_spindle_1.jpg

Here it is all together. The back gear has no where to go.

http://bp3.blogger.com/_Mv0bGRyF_LA/R1OA0lzUjDI/AAAAAAAAAFM/6nlpvy_yVjI/s400/rebuilt_spindle_3.jpg

So far so good. The next task is to address the wear on the bull gear and cone pulley's hubs caused by the weird thrust path. Those parts are eating themselves. I intend to remove almost a 1/16" from the hubs of each and drop a oilite washer bearing in there.

-=-=-

My journals aren't great, but these pictures make them look to be worse than they are. They're being accentuated by the camera's flash and the WD40 I just applied to prevent rustage.