Craftsman/Atlas 6", what have I gotten my self into?

[wa5cab]

Yes, Six thou up and down is excessive. I thought that you had written earlier that after replacing the bushings, you could tighten the clamping screw down enough to make the spindle difficult to rotate.

 

[kopeck]

I did. That's the weird thing, I can tighten them up to the point where there is considerable drag, almost to the point of the spindle not turning at all and there is still a little play.

You would think that the clamping force being vertical would remove the play there first. The horizontal play is more or less in my option acceptable, I just can't get the vertical play to go away. It seems to be all in that front bushing too, I can crank down on the rear one and it has pretty much no effect on the play.

The holes in the head stock looked perfect, brand new bushings, a a little wear in the spindle but wouldn't you think the play would be more uniform?

K

 

[kopeck]

Just thinking out side the box here. I wonder if a little shim stock between the housing and the bushing on the top might help?

I'm at the point where I really don't want to throw good money after bad. It needs a lead screw too so I have to keep that in mind.

K

 

[francist]

To my mind I'm thinking your shim stock idea may be a useful thing to try if you can get the bushing out of the cap easily enough. Not necessarily for a permanent solution, but it might give you an idea of what's going on. Or contrarily, what's not going on.

You might also want to verify that there is enough clearance between the front pair of bushings so that they will indeed draw up snug against the spindle. I don't have a plain-bearing machine, but I'm imagining a situation where the spindle may be worn enough on that front end so that the two bushing halves could close tight together but still fit loosely around the shaft. Just make sure you don't screw up the new bushings in that process though -- that would really tick you off.

If you haven't done it already, I would also take the chuck off that machine for any further measuring. If the error is in the spindle you should still see it without the chuck being mounted.

-frank

 

[kopeck]

The bushings are one piece, just simple bronze Oilite style bushing. There is no cap, the hole for the busing is machined into the head stock and then there's a slot cut in onside that is snugged up to take up the clearance. More or less you are crushing the bushing. Here's a decent picture:



I think what might be happening is since the force is pulling on only one side there's kind of a hinge like effect going on. Pretty much even though the screw is pulling down it's also pulling in which tightens up the play side to side but could also making he bushing go out of round and and create more space on top.

I could be way off here. I think I need to pull the spindle and inspect further. I kind of think I know why it was for sale now...

K

 

[Z2V]

I know you have unwanted play in your spindle but I was just wondering if you had your work supported on the end with tail stock or rest. On mine I had to support anything sticking out of the chuck more that an inch or two if I was going to get any kind of decent finish. With the work supported it did a pretty good job with the tool dead center. I had the small insert set from Anytime Tools, also used HSS that I ground using Mikey' method. Without support there was little hope in a good finish. I know this won't help your spindle issue but it might help otherwise.
Jeff

 

[francist]

Ahh, sorry, I misunderstood the operation of the bushings. Thought they were a two-piece affair with removable cap. I'll assume then that the slit in the bushing is lots wide enough to accommodate some wear in the shaft and still close up snugly. And if that's the case, I remain puzzled as to why they won't close down enough to eliminate the vertical play yet you are able to eliminate side to side play.

-frank

 

[markba633csi]

You might want to take a look at Deans website he has about the most thorough run-thru of the bushing replacement on these machines,
scroll to the bottom of the page to the Atlas 618 section.
Your spindle might be more worn than you realized. Or perhaps one of the bushings you got was not correct.
Anyhow, check it out. Don't give up too soon- you're just getting started
www.deansphotographica.com
Mark S.

 

[kopeck]

I know you have unwanted play in your spindle but I was just wondering if you had your work supported on the end with tail stock or rest. On mine I had to support anything sticking out of the chuck more that an inch or two if I was going to get any kind of decent finish. With the work supported it did a pretty good job with the tool dead center. I had the small insert set from Anytime Tools, also used HSS that I ground using Mikey' method. Without support there was little hope in a good finish. I know this won't help your spindle issue but it might help otherwise.
Jeff

No, you are 100% right, it's something I need to try. I just got a new dead center, it's on my list of things to try. The piece I was working on was sticking less then 2" out tough.

I just need to get some material and some time!

K

 

[kopeck]

Ahh, sorry, I misunderstood the operation of the bushings. Thought they were a two-piece affair with removable cap. I'll assume then that the slit in the bushing is lots wide enough to accommodate some wear in the shaft and still close up snugly. And if that's the case, I remain puzzled as to why they won't close down enough to eliminate the vertical play yet you are able to eliminate side to side play.

-frank

Yeah, I don't quite get it either. Like I said it could be a sort of uneven pressure due to hinge like effect.

Pretty sure the worn spindle is the root of the problem though.

K