What follows is my experience with servicing the spindle on my lathe. I urge you to approach this with caution - if the spindle or bearings are inadvertently damaged, things are going to get expensive. Many thanks to Tony Watson and Neville Chase for sharing their experiences with me - it allowed me to proceed with confidence. In addition to this document, you may also want to read Neville Chase's experience with a roller bearing spindle since there are clearly similarities between the two.

Disassembly

• Loosen grub screw 'A' and remove gear.
• Loosen grub screw 'B' and remove end float collar. I used a rounded punch located in the hole that can be seen above the grub screw to tap the collar undone.
• Loosen grub screw 'C'.
• Since I was going to be readjusting the bearings, I removed the adjusting bolts 'D'.
• Push the shaft from the left hand end. I was able to do this by hand, otherwise a soft faced mallet should do the trick. As the shaft is drawn the rest of the way out, remove each of the thrust bearing assembly, pulley assembly and bull wheel as they become free.

• The spindle is easier to manage if the chuck is removed first.
• There is a small woodruff key that engages the bull wheel 'E'. Take care not to loose it and try to avoid letting it score the bearing.

There are any number of places problems could occur with the spindle. With mine, a burr had formed around the small hole which the pulley grub screw 'C' locks into. This was preventing the pulley from spinning freely when using the backgear. I filed the burr off and ensured the pulley would spin freely. The front bearing also showed some scoring, however there were no raised burrs and I was in no hurry to pay a machine shop to engineer a solution so it went back in as-is. It ended up being fine.

Reassembly

To assemble, simply reverse the disassembly procedure. Other than the fact that the shaft has several steps that catch just as you're trying to push the shaft through a new piece, it is quite simple.

• To assist with locating the woodruff key with the bull wheel I marked the key way location on the teeth of the bull wheel and on the spindle nose.
• The small gear is aligned with the pulley by a pair of pins. With my parts, the gear would only fit correctly in one of the two possible orientations. Marking the orientation before separating the two pieces would be a good idea.

I was very worried here about breaking the bearing caps. Fortunately all went well. Loose, my front bearing had 4-5 thou of movement. The rear bearing had significantly more movement but only in the vertical direction.

First attempt, I tightened the front bearing down to around 1.5 thou of movement and the rear bearing to a few thou. I adjusted the end float as tight as possible while still allowing the spindle to spin freely. The results weren't too good, I was always working to avoid chatter.

Second attempt, I tightened down the bearings some more. I left the end float setting the same. The front bearing now has very little movement and the rear movement is barely perceptible. The spindle still spins freely by hand and the bearings do not get hot when running. Performance of the lathe is now great. Attempting to cut too much (or too quickly) simply results in strong resistance against the tool, whereas before chatter would be guaranteed.

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