Newbie needs help with Logan 200 spindle runout

Ok, I need to tool up :) I will need to buy a boring bar and a 0.0005 dial test indicator. The wife will be pleased with the news :)

Here is a video inspecting the backplate, threads, and it running on the lathe just by itself.

 
It looks like you motor is loose too...seems to be shake, rocken and rolling down there in the video....lol
 
If you are going to sell the Logan you might not want to do more than just finishing the backplates, your runout tests look ok to me.
Mark
 
I see my name was mentioned earlier. Thank gosh you guys didn't use it in vain! :laughing:

I do have a Logan 200, and I will get a couple of spindle photos and measurements for you later today if you wish. Just let me know.

Everything that everyone has said so far appears to be correct. You want to address any spindle runout issues before you attempt to correct any registration issues on your chucks or faceplates. Runout of .001" on the spindle seems like an awful lot to me, though I do not know what the factory spec was off the top of my head. Logan lathes were not Monarchs, Hardinges or LeBlonds, but I would still expect smaller numbers than what you are seeing on the spindle. It also appears to me that the runout on the registration boss was less than the runout on the inside of the taper which is a red flag for me. They should be very close to the same and should be concentric, in other words they should both be off the same amount at the same point in rotation of the spindle. From my experience, differences in the two often occur due to nicks or burrs on the internal taper. For some reason people are often not very careful about their treatment of those internal tapers.

Richard also mentioned warming up the bearings before taking any measurements, as this tightens things up and will give you more accurate readings of what is actually happening with your lathe.

Once you are satisfied with your spindle runout, you can then do something with the registration cuts on your chucks and faceplates, which are obviously not correct for that lathe. The reason that you need to address the spindle issue first is because any work that you do to the faceplates or chuck backplates is dependent on the runout that your spindle has currently.

Here is how I would approach your issue:
  1. Get a .0005 or a .0001 test indicator
  2. Recheck your spindle runout after allowing your lathe to run for a while and getting everything up to operating temperature.
  3. Examine the internal taper of the spindle very closely for any nicks, burrs, or other high spots. Any high spots can be removed with a fine stone.
  4. If the spindle runout is significant, beyond what you feel is appropriate, address that problem first. I would be looking for .0001" or less at the spindle.
  5. Properly bore the registers in your faceplates and chuck backplates.
  6. Remount your chucks on the backplates.
Don't expect used chucks to get you down to little or no runout. As scroll chucks (3 jaw) wear, their ability to center the jaw accurately decreases. You will also find that their runout will be different with test bars of different diameters. I have a newer Shars 6" 3 jaw chuck for mine, and I get .0003" runout on a 1" test bar mounted in the chuck. Very good in my opinion, but I think I just got lucky when cutting the registrations on my backing plate.

One last thing to keep in mind: the generally accepted practice when fitting a different chuck to a lathe is to replace the back plate so that new registrations are cut to fit that lathe. The chuck is then mounted to the back plate as machined for that lathe.
 
The spindle runout is definitely a problem. As a comparison, my Logan has less than 0.0001" of runout on the spindle. I think you would want to fix that if you were keeping the lathe, maybe not if you're going to sell it.
 
Hi Terry thanks for jumping in- to me it looked like the taper measurement was "ticking" periodically so I figured burrs and dirt. Less so on the outside measurements. Dirt and residue can throw off my caliper by half a thou or more so that's what I thought he was seeing- not a big deal compared to the backplate/threads issue especially for a machine he may not keep.
Mark
 
markba633csi said:
Hi Terry thanks for jumping in- to me it looked like the taper measurement was "ticking" periodically so I figured burrs and dirt. Less so on the outside measurements. Dirt and residue can throw off my caliper by half a thou or more so that's what thought he was seeing- not a big deal compared to the backplate/threads issue especially for a machine he may not keep.
Mark
Click to expand...

That's what I was thinking.

I have always been mystified at how damaged the internal tapers can get over time. I believe that people think of the spindle taper as being 'durable' and they care little about how they go about putting things inside, especially when putting in pieces of stock that fit through the bore. A little rough handling of such pieces is all it takes to nick up the inside.

At any rate, those nicks and burrs need to be removed if a person plans to use a collet adapter or any MT centers in the headstock.
 
Ok stay tuned... I just ordered a 0.0005 dial test indicator and will be in 3 days. In addition, I will probably order a quick change tool post that I will use on the Logan, and keep for the South Bend when I sell the Logan. It will have a boring bar with it when the spindle gets sorted out. I will reread all the posts above and report back with measurements and video. Many thanks to all of your contributions... I am new, but able to learn.
 
Another thing you could do to see or actually hear if the spindle bearings are bad. In the old days I took a long handled 16" screw driver and put the handle end in your ear and the blade on the bearing housing and listen. Turn off the spindle and listen until it stops turning. A bad bearing sounds as if rocks rein there when it coasts to a stop. If you want to feel like a doctor go to an auto store and buy a stethoscope .
 
Richard King 2 said:
Another thing you could do to see or actually hear if the spindle bearings are bad. In the old days I took a long handled 16" screw driver and put the handle end in your ear and the blade on the bearing housing and listen. Turn off the spindle and listen until it stops turning. A bad bearing sounds as if rocks rein there when it coasts to a stop. If you want to feel like a doctor go to an auto store and buy a stethoscope .
Click to expand...

Roger that... wife is a nurse and we have one of n the house. Will try that. The spindle really does feel solid. I used full force back and forth and feel no slip or movement. However I’ll listen with a stethoscope. Thanks Again!
 
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