How do I eliminate vibration on narrow turnings?
As the long spindle I was turning became narrower, it began vibrating with a whipping motion. How do I eliminate the vibration?
—Roger Hastings, Escondido, Calif.
If sections of your spindle are still rough, Roger, first turn the entire spindle down to a cylinder. This ensures that the stock is centered and balanced on the lathe. Slow the turning speed down and keep your tools sharp to dampen any chatter.
If you find that the spindle still gets whippy, consider using one or more commercially-available spindle steady rests for added support on the spindle's narrower sections. For a low-cost solution, make your own simple steady-rest, like the one shown above.
Begin by laying out the shape on plywood, centering the rest's opening on your lathe's chuck. Mark the positions of the four screws such that an X drawn between them crosses at the center point. Then, bandsaw the frame to shape and drive the screws. Screw a small office binder clip to the lower left of the rest's base. Next, attach a block of wood with a bolt and wingnut to clamp the rest to the ways of the lathe bed.
Tie a sturdy string to the bottom left screw. Then, with the spindle chucked in the lathe and centered in the rest, wrap the string around the screws in this sequence to capture the spindle: top right, bottom left, bottom right, top left, and bottom right. Finally, clip the end of the string into the binder clip to hold it tight. Make as many string steadies as you need to support the narrow sections of the spindle.