Question re rebushing Atlas 618 countershaft Hanger spindle

[wa5cab]

Yes. And sorry, I thought that one was at least as common as AFAIK. Anyway, JIC = Just In Case. And in the present context, use of it would generally imply that you probably won't need the extra one but there's always Murphy's Law and they're pretty cheap.

 

[Woodsman 22]

Yes. And sorry, I thought that one was at least as common as AFAIK. Anyway, JIC = Just In Case. And in the present context, use of it would generally imply that you probably won't need the extra one but there's always Murphy's Law and they're pretty cheap.

Don't be sorry- I had mental blinders on because I was so focused on tools and procedures and not thinking internet abbreviations. And yes, Just In Case is as common as As Far As I Know. But, I was one step ahead of you guys on this one little detail- yesterday when I ordered these bushings from Clausing I did order extra only because Mr. Murphy lives in my basement "shop", you see

 

[wa5cab]

 

[Woodsman 22]

Okay; the replacement bushings from Clausing arrived today, and they are a bit of a disappointment in that they are too short in the length dimension.
Following are the relevant dimensions:

The original bushings (which I am convinced were replacements for the Atlas bushings) are 1.130" in length
The replacements I got from Clausing are exactly 1.00" in length, so .132" too short.
The new bushings average .6275" in O.D.
- Inside diameters of the new bushings vary from .5011" to .5025" (I bought four of them) "JIC", lol.
The countershaft bores measure o.6249" on one side and 0.6255" on the other side.
I installed one bushing and the I.D. shrank to 0.4985"

I then tested the fit of the new spindle and it did slide in with a bit of effort. Encouraged, I then installed another bushing in the opposite bushing housing. This is when things got interesting. That one was a tight fit- but... when the spindle is slid into one bushing and then over to the other, there is misalignment.
Switched to inserting the spindle from the opposite bushing the misalignment is much less and almost wants to fit into the opposite bushing.

Held up to a light source there is a visible gap, but not a great deal of it. Just enough to prevent entry.
Since the new spindle is very straight, I suspect that the countershaft hanger assembly is bent. It cannot be seen with the naked eye, but I am convinced of it.

Solutions? I can live with the too short bearings- there were many variations of this Atlas 618 lathe with several countershafts, so I suspect inventory is down to these particular bearings. But the misalignment is a problem that I am not sure how to solve. Ream the offending bearing slightly larger ? A touch of (fine) sandpaper to that side of the spindle? Make a lead lap to slightly enlarge the bearing on that side? I am out of ideas and would very much appreciate guidance.
Thanks once again for putting up with all my questions.

 

[westsailpat]

I agree with "ream offending hole" . The countershaft is not as a precision thing as your spindle . "When in doubt ream it out", don't over think it . Also on second thought , ream out both sides to give a little better clearance for the slight misfit fit and maybe like you say polish down the one side of the countershaft .

 

[Woodsman 22]

I agree with "ream offending hole" . The countershaft is not as a precision thing as your spindle . "When in doubt ream it out", don't over think it .

Yes, I was thinking that might be the best solution, although I was hesitant. Now... which type of reamer;
chucking reamer, adjustable reamer, or should I just go low tech and try fine sandpaper wrapped around a slightly smaller sized piece of round steel stock. Guess I am still over thinking it

 

[westsailpat]

IMO it depends on how much over size you want to go . A regular chucking reamer might be hard to start or not . Is there a nice chamfer in the bush ? can you hold it straight ? One thing about the adjustable reamer is you can insert it small and then adjust bigger while it is still in the hole . And I would use a tap handle and oil .

 

[Woodsman 22]

IMO it depends on how much over size you want to go . A regular chucking reamer might be hard to start or not . Is there a nice chamfer in the bush ? can you hold it straight ? One thing about the adjustable reamer is you can insert it small and then adjust bigger while it is still in the hole . And I would use a tap handle and oil .

No chamfer unless I put it there myself. I am working on a lathe setup to hold it rigid- that is the hard part and very necessary for the chucking reamer if I go that route. OTOH, the adjustable reamer sounds like it might be easier to sneak up on a bore just oversized enough to run straight in this bent countershaft hanger.
My mill is too small to handle a job like this and the only other option would be to use my drill press and I don't see how that would be accurate enough (I can turn the table on that press so that it is vertical with the spindle).

 

[wa5cab]

Well that all does sound a little disappointing. However, as you say, the hanger might have warped a few thou over the decades. What I would do, because it will (assuming that the shaft is the same diameter at both ends), solve all of the problems at one time and with the minimum stock removal, is to use an adjustable reamer long enough to cut both bushings at the same time. Grab the hanger in a stout bench vise equipped with soft or hardwood jaws. Shrink the reamer and slide it through both bushings. Slowly enlarge it until you can't easily rotate it with your fingers. Use only a T-handle tap wrench turned with your wrist so that you never put any side load on the reamer, If the reamer set has a chart showing how much the reamer diameter increases per one revolution of the two nuts, try to go in 0.001" increments. It won't take much. Go slow, because you can't back up. Keep both bushings oiled. The correct fit is a slip fit.

 

[Woodsman 22]

Well that all does sound a little disappointing. However, as you say, the hanger might have warped a few thou over the decades. What I would do, because it will (assuming that the shaft is the same diameter at both ends), solve all of the problems at one time and with the minimum stock removal, is to use an adjustable reamer long enough to cut both bushings at the same time. Grab the hanger in a stout bench vise equipped with soft or hardwood jaws. Shrink the reamer and slide it through both bushings. Slowly enlarge it until you can't easily rotate it with your fingers. Use only a T-handle tap wrench turned with your wrist so that you never put any side load on the reamer, If the reamer set has a chart showing how much the reamer diameter increases per one revolution of the two nuts, try to go in 0.001" increments. It won't take much. Go slow, because you can't back up. Keep both bushings oiled. The correct fit is a slip fit.

Thanks for that procedural information. I have been looking for an suitable adjustable reamer, but most of them are huge. Have not been able to find one in the .500" + size range unfortunately. Not yet anyway. I never thought of putting the hanger in a vise to do this (thought it had to be precisely aligned between centers in the lathe). Anyhow, I have two questions for you:
1) the bushings Clausing sent are too short by one tenth of an inch, will this make a difference in how it performs?
2) After reaming, would it be advisable to drill a small hole in the bushings where Atlas provided an oil hole in the bushing housing?
Atlas' reasoning was that being oilite bushings, they supposedly did not need holes drilled in the bushings themselves, because the oil was supposed to soak into the pores of the oilite bushing. I find this hard to accept
and have the urge to put those holes into the bushings. Where does your experience and observation put you on this matter?
I want to thank you and all those who have contributed their experience and help to me with this problem. I realize that it is an elementary matter to most of you, but you took the time to put up with my many questions and I want to express my appreciation.