9A Spindle Adjustment

In Steve Brooks' excellent book, A Guide to Renovating the South Bend Lathe 9" Model A, B & C, he states that after properly adjusting the take-up collar the, "spindle should turn easily."

The "Headstock Bearing Adjustment" PDF on Wells' excellent web site at <http://www.wswells.com/data/howto/Spindle_Bearing_Adj_9_10k.pdf> says to "... be sure spindle turns freely."

I know I'm being Mr. Pedantic, but I'd like a less subjective metric than easily or freely.

With the reversing gears disengaged, and the belt take-up collar and bearing cap screws loose, I can't get the spindle to turn more than one and a half revolutions when I spin the bull gear as forcefully as I can. Is this normal, or should the spindle rotate for several turns before stopping?

And for some reason, the spindle turns more smoothly in the reverse direction.

The spindle sounds like its bearings are dry, even though the oil cups are full. I slid out the shims and can see a film of oil on the spindle, so I think it's properly lubricated.

What do you think?

Thanks!

Jan (Yan)

The fact that it operates better in reverse, indicates to me that something is jamming, or binding the spindle. Having oil cups full of oil does NOT mean that oil is getting to the spindle.

What kind of bearings do you have?

I would pull the spindle, check for foreign matter, then carefully reassemble, following the reassembly procedure.

Was this the lathe that had shims only on one side?

SLK001 said:

The fact that it operates better in reverse, indicates to me that something is jamming, or binding the spindle. Having oil cups full of oil does NOT mean that oil is getting to the spindle.

What kind of bearings do you have?

I would pull the spindle, check for foreign matter, then carefully reassemble, following the reassembly procedure.

Was this the lathe that had shims only on one side?

Click to expand...

Thanks, SLK.

This 1948 9A has plain bearings and shims on both sides.

I did as you suggested. I pulled the spindle and inserted it alone, after removing the wicks. The feel was about the same, and I could hear scraping from the small side.

I inspected the small side bearing surface on the spindle and found what looked like a small (1 mm?) bump. I stoned it lightly until it appeared to be flush with the surface and reinserted the spindle. Better, but still not silent and smooth.

I then stoned the bump more aggressively with a diamond hone and was surprised to see it had disappeared. Embedded chip, maybe?

The spindle now rotated quietly and fairly smoothly, but still seemed to rotate more smoothly in reverse.

The bore had a score mark in it in the location of the bump. I smoothed it as best as I could, and that made an improvement.

I now wonder if I should lap the bores -- which aren't in as good condition as I first thought they were.

The only thing wrong with the lathe is your desire for artificial perfection. Put it back together and use it, you are about to do more harm than good.

allan

Don't lap the bores.

Are the wicks new?

If they are old, they might have picked up a "set" which explains the "better one way than the other". By "set", I mean they bend in the primary direction. In the opposite direction, the set is against the spindle, so a little more friction. Have the wicks ever been removed, ie, for cleaning?

Anyway, you have eliminated the spindle noise and the spindle now turns freely. Leave well-enough alone and be happy that the spindle now appears to be happy. A scored bore isn't that big of a deal - there's still plenty left that isn't scored.

You might want to inspect your wicks for the direction of the set and rotate the one(s) that are in the reverse direction (the ones that are pointed "forward"). This will make the forward direction the freest and smoothest. Then reassemble and be happy!

Spindle now seems to be happy. Spins the same in both directions -- about two revolutions after a hard pull on the bull gear.

Thanks for the help.