Newbie needs help with Logan 200 spindle runout

Ok yes after reading all the posts I think the tooling is from another lathe. I see what everyone means now. I attached 2 pics of the spindle.

I bought a SB 10k with QCGB that I can set up to do the relief cuts [I'm trying to sell the Logan and set up the SB :)]. Maybe I should just buy a proper 3 jaw chuck on eBay made for Logan and call it a day.

IMG_6161.JPG

IMG_6162.JPG
 
Check the bearing replacement that the PO performed. Logans are stout, and the spindles have proper bearings in them, but as with everything else with machine tools it has to be done properly.
I grabbed an extra 3-jaw off of EBay several years ago, cleaned it and slapped it on and had only .0015 runout.
They do have to register properly as noted above.
 
You need to perform the cuts on whatever lathe you're going to use the chuck on. Even though the Logan and the South Bend both have 1-1/2" - 8 threads, the spindle noses are different.

Take the back plate off of the chuck. Thread it on the spindle backwards with a spacer between the face and the spindle shoulder. Cut the thread relief with a boring bar, then face off the shoulder of the back plate so it is square. Then, turn the back plate around and thread it onto the spindle in its normal orientation. Ensure that it is seating against the spindle shoulder. Then take a light facing cut on it so that it is running true to the spindle axis. You may also need to recut the register to match your chuck. Now mount the chuck back on it and test the runout.

Edit: Even if you buy a new chuck for the Logan, the above procedure will still need to be done with the new back plate.
 
Any thought the spindle isn't installed correctly . And isn't seated in the bearings , or its been abused.
 
You need to perform the cuts on whatever lathe you're going to use the chuck on. Even though the Logan and the South Bend both have 1-1/2" - 8 threads, the spindle noses are different.

Take the back plate off of the chuck. Thread it on the spindle backwards with a spacer between the face and the spindle shoulder. Cut the thread relief with a boring bar, then face off the shoulder of the back plate so it is square. Then, turn the back plate around and thread it onto the spindle in its normal orientation. Ensure that it is seating against the spindle shoulder. Then take a light facing cut on it so that it is running true to the spindle axis. You may also need to recut the register to match your chuck. Now mount the chuck back on it and test the runout.

Edit: Even if you buy a new chuck for the Logan, the above procedure will still need to be done with the new back plate.

Roger that, thank you for taking the time to explain it. I will need to tool up (get a boring bar, etc) for this. I look forward to it. Thanks to all who have helped along the way!
 
I hope we're all on the same page, but just to clarify, I believe there are two separate issues here:
  1. The spindle runout.
  2. The improperly fitted chuck(s).
I've limited my comments to the chuck issue, as I've not disassembled my spindle and have no experience to add to the conversation.

Carry on:)
 
Any thought the spindle isn't installed correctly . And isn't seated in the bearings , or its been abused.
That was my first thought... so I bought the dial indicator to start checking. The first video shows about 0.001 runout measured on the spindle itself. Visual inspection shows it to be ok and free of catastrophic crashes.
 
Oh, and if you determine that the spindle issue needs to be addressed, do that before fixing the chuck!
 
I agree with Richard - you need to determine how accurate the spindle is. I'm sure the guys are right and the excessive runout of your chucks have to do with how they fit on the register but that is a separate issue. You first need to know how accurate the spindle is. I would suggest you begin with using a 0.0005" dial test indicator, not a drop indicator, and measure for concentricity in the taper at several points to make sure the readings are consistent. If the spindle is accurate then check play in the spindle bearings as Richard suggested; if there is a lot of play then the spindle bearings may need adjustment or possibly replacement. If there is no significant play then your spindle is okay and you can focus on the fit of your chucks on the register.

Nailing down the source of runout is a process of elimination and you need to diagnose it before taking corrective measures.
 
I hope we're all on the same page, but just to clarify, I believe there are two separate issues here:
  1. The spindle runout.
  2. The improperly fitted chuck(s).
I've limited my comments to the chuck issue, as I've not disassembled my spindle and have no experience to add to the conversation.

Carry on:)

Indeed... I will take care of #2 first, then go after #1. In your opinion how bad is the spindle runout? Is there another measurement you want me to take?
 
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