Turning Archive 2007

Subject:
Arrrgh… My live center bearing is toast.

Brian Hahn in SW Wisconsin
>Yesterday I was turning a 3” ball. It’s only the third one I’ve made and the others were two years ago. It was coming along nicely until the top bearing in my Nova live center decided to call it quits. The cup centers (drive and tailstock) left beautiful deep burn rings on the ball. I managed to finish the ball with a different live center, but it wasn’t pretty – having to use the other center, not the ball which turned out “perfect”.

I used a bearing puller to take the center apart. The Nova has 3 bearings and they were an interference fit on the shaft. I had to use a bearing separator to separate them and then pull them off individually. They protested every millimeter of the way. The top bearing definitely was toast.

I ordered a new complete set of bearings, but this is the weekend and they won’t ship until Monday. So they should arrive Tuesday just before I leave for the Badger Woodturners’ meeting. Putting the new bearings on could be interesting. But that’s why they make jumbo sized “persuaders” (sledge hammers). Actually, I’ll use a bolt to draw them on to the shaft – maybe I should pick up a grade 8 bolt on Tuesday just to be safe. I might even have to stick the shaft in the freezer to facilitate the process.

Meanwhile, I’ll try running the live center with just two bearings – one at the top and one at the bottom. I’ve gotten so accustomed to the versatility and features of the Nova, that it is difficult to use a lesser live center. The Nova is 10 years old, so I certainly have no complaints about its performance.

The bottom line: $18 for bearings vs. $108 for a new live center.

The moral of this story: If you are mechanically included, a bearing puller is a very worthwhile investment. My $40 3-jaw puller has paid for itself every time I’ve used it.

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