Question about spindle runnout on a 6" Atlas

I have a 6x18 Atlas that I purchased from a friend. I've started using it to make a model steam engine and was having trouble making accurate parts with the 3 jaw chuck. I bought a dial indicator and found that the chucked parts were wobbling about .013" (not a typo). I thought maybe the chuck jaws were warn so I took the chuck off and put the indicator on the spindle and saw the same runnout. What are reasonable runnounts for a hobby lathe? Under .003"?

Now I may be completely off in how I am measuring, but if not, what are the ways of fixing this problem? Is it mounted incorrectly (see picture below), is the bearing shot? (When I chuck parts in the 4 jaw, I can get the indicator so that the part is under .005" so I think I'm using the indicator correctly).

I've switched to using the 4 jaw chuck and have been getting better results since it seems that I can actually center parts. I've been reading the Sheldon Lathe manual (from Lindsybks) and "Machining Fundamentals" but they don't have much to say on maintenance and repairs.

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Thanks for advice, Aaron

Reply to
Aaron Kushner
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If you put the indicator right on the spindle nose as it emerges from the headstock casting, you should see 0.001 or less, even on a machine of that vintage. If your indicator is reading 0.013 TIR at that point there is something up with the spindle and that should be corrected.

If the spindle itself were bent however you would not really be able to compensate for that by using a four jaw chuck.

Have you really unscrewed the backplate from the threaded spindle when making your 0.013 measurement mentioned above?

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

Reply to
jim rozen

Not sure what you mean by backplate. I removed the chuck and measured close to the headstock (between the headstock and where the threads of the spindle started).

At first I put the indicator on the smooth part of the chuck (between where the jaws and locking collar) and got a similar reading as when I removed the chuck and measured from the spindle.

Reply to
Aaron Kushner

Your spindle is bent. Your lathe is seriously damaged. Someone crashed it when parting off or something like that.

When you buy a lathe, especially a small one, ALWAYS check the runout on the spindle.

I suggest you sell your lathe as parts on ebay, then look for a better one. Sorry.

Grant

Aar> jim rozen wrote:

Reply to
Grant Erwin

If no answer shows up you might try asking at

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Aquiles Rubina Lima, Peru

Reply to
Aquiles Rubina

The compound looks like it has met with the chuck jaws on more than one occasion. Would that cause a bent spindle?

Thanks for the info. I kind of suspected it wasn't going to be good news.

I bought the atlas for $500 and can probably sell the parts for close to that (I've got two milling attachments, steady rests, etc). I suspect getting a new headstock would be a waste since the ways are pretty worn out also.

Now the friend who sold me the Atlas is trying to sell me a Logan

820 for $1500. He wants it out of his shop so he can have more room for woodworking equipment (so he says...)

What should the runout be for the Logan? I read the "Some Helpful Tips on Evaluating a Lathe"

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and have been reading this group for a few months now so I hope I'm in a better position to judge a lathe.

The other lathe I'm considering is the Grizzly 11x26. It seems like it fixes some of the shortcomings of the 9x20 lathes and has a 1" spindle bore which seems like a plus. I haven't been able to find any good writeups on it, however.

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Thanks for the comments.

Aaron

Reply to
Aaron Kushner

I tend to agree with Grant. I have an old Atlas 618 (101.21400, early SN) and when I measure the spindle runout, I can hardly see movement in the DI -- maybe .0002 or less. Your's is definitely toast.

You could either rebuild it or replace it.

Interesting picture -- looks like some sort of stop bolted between the ways under the chuck. Did you install that? Or did the previous owner do it after crashing in one day?

-Bruce

Grant Erw>Your spindle is bent. Your lathe is seriously damaged. Someone crashed

Reply to
Bruno

Reasonable on any lathe is under .0003". Indicate the taper in the spindle, it should be less than .0001 if the machine is in good shape, somewhat less if it's been through the mill. Runout on my Taig was under anything reliably shown with a one tenth thousandth indicator. .013" sounds like a bent spindle. The 6" Atlas I had showed nothing when I got it, but it was new, had never been used, although over 15 years old then.

Reply to
Lennie the Lurker

Eeek. I'm a couple of orders of magnitude off...

Good eyes Bruno. That "stop" was me starting to make a rest for holding woodworking chisels when I realized that the lathe might not be good for much else.

Reply to
Aaron Kushner

This machine does have timkin bearings. It's possible that they're very loose and that is giving the large runout number.

He can easily check for that.

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

Reply to
jim rozen

Runout on any lathe you buy should be well under .0005", in other words damn hard to see unless you have a fifty millionths dial test indicator.

Your friend ought to cut you a heck of a deal considering how he burnt you last time.

One thing about those little Atlas lathes is they have flat ways. You can strip it all the way down and put it on a big surface grinder and in a minute or so your ways will be like new. I don't know about alignment afterwards, though. I'm not a fan of those little lathes since I found out the change gears are made of pot metal and they aren't terribly stable with time. My ex-father-in-law (a heck of a good guy) had a couple of those because they were all he had room for. On the first one, the gears just crumbled away after about 30 years.

I would not buy *anything* from Grizzly or Jet or anyone like that. No Asian small lathes period. Where are you located? It's an ideal time to find quality used manual machine tools.

Grant

Reply to
Grant Erwin

San Francisco area. I just read the Asian vs. American thread from January.

So it seems I should be looking for a good quality SB or Logan. Is a budget of $1,500 for the lathe and $500 for tooling unrealistic for a good quality older lathe? I'm looking for something that doesn't take up too much space.

Buying off ebay would seem to be hit or miss considering that is where the Atlas and Logan came from. My friend with the Logan says he thinks the 820 has .003" runout. I'm going to check it out on Sunday.

Thanks for all the info.

Reply to
Aaron Kushner

Aaron $1500 for an 820 is a high end price. For that price I would expect a machine in very good condition with both steadies, chucks, and a fair amount of tooling. It should also have a quick change gearbox on it. A Logan is a good lathe for the home shop, it has good support from the factory and many used parts available for it. lg no neat sig line

Reply to
larry g

Reply to
Grant Erwin

*SPINDLE* runout on a new Logan 10" lathe was measured using a precision ground test bar mounted in the internal taper of the spindle. TIR on the end of a 12" test bar was to be no more than 0.001".

*SPINDLE* runout on the internal taper, spindle nose and face of the spindle shoulder were all 0.0005" or less.

I am emphasizing the *SPINDLE* readings to denote that none of these tests are done using a chuck or collet.

Reply to
Scott S. Logan

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