Turning

Subject:
I can believe it

John K Jordan
>>>I was sanding the inside at a slow speed and it started to wobble so I grabbed the bowl, it was then that I noticed it was unscrewing from the shaft.

I remember someone on another forum reporting a similar incident. I can imagine the harmonics of a vibration at the right frequency working to unscrew the chuck in the opposite direction of rotation.

(Not exactly the same thing but just yesterday I had vibration from a polishing operation loosen a tight thumb screw and spin it off the thread and throw it across the room!)

Do you have locking set screws for your chuck? That should prevent a recurrence.

I tighten chucks by hand, giving the chuck a spin with a "calibrated" flick of the wrist for the last 1/8th turn or so. I have been doing this for years and never has one come loose, even when turning in reverse. (I don't use the locking set screws)

I make sure the seating surfaces are clean before installing the chuck. The chuck is "locked" on so tight it takes a hefty tug with the chuck wrench to remove it. (I always use a chuck wrench.) My wrist is calibrated to apply more flick for a larger piece!

As for sanding, I've given up power sanding with a rotating disk and mostly quit any sanding while the piece is rotating. I use NRS and hand scrapers to remove gouge marks and small (1", 2", and 3") pneumatic random orbital sanders to remove the scraper marks. Little dust, better surface.

JKJ

© 1998 - 2017 by Ellis Walentine. All rights reserved.
No parts of this web site may be reproduced in any form or by
any means without the written permission of the publisher.

WOODCENTRAL, P.O. BOX 493, SPRINGTOWN, PA 18081