3520b issue

[bob svoboda]

My 3 year old 3520b has an issue. When working with an 8" HF everything was fine until I released tailstock support to refine the end and begin hollowing. When the support was taken away, I heard a sound I can only describe as 'howling' from the area of the headstock accompanied by a vibration that definitely affected my ability to make a smooth cut. Can this be anything other than headstock bearings? Any advice or experience would be greatly appreciated. Thanks.

[Reed Gray]

Sounds like it could be bearings, but I am not sure. I did go through a set of bearings on my A when I had it, after about 5 years of heavy turning. Blanks up to 16 inch diameter and no tailstock support. It didn't howl, but sounded more like grinding, and the spindle did not spin freely. I was sanding at the time which was done at much slower speeds.

robo hippy

[robert baccus]

Bob, I'm betting that if you check the headstock locking mechanism and the RPM indicator you will find one of them loose. I quit using both years ago. Good luck. Also check around the chuck?

[bob svoboda]

Reed and Robert-Thanks for the responses. When not cutting, everything runs smoothly and quietly. I will check the locking mech. and the RPM indicator and see where it leads me. Thanks again.

[Ken Fitzgerald]

Is there any chance the drive belt is slipping?

[Jeff Nicol]

It could be that while turning the form with the pressure on the blank, the wood may have shrunk a tiny bit or the jaws of the chuck were not tightened all the way allowing some sort of vibration causing a harmonic whine. If you can turn it freely and no sounds or feeling roughness while hand turning the spindle should not be the bearings. I have had the ring gear in a chuck make noises just by being in a certain spot where the jaws stay in place but the teeth of the gear have loosened just enough to cause the vibration. I always tighten the chuck before taking tailstock away or before starting hollowing.

Just my observations,

Jeff

[bob svoboda]

Thanks Ken and Jeff. I have checked the drive belt and it is not slipping. The noise happens with extremely light cuts. Jeff, I did retighten the chuck so don't think it's that, but when you describe a 'harmonic whine', it sounds like what I am experiencing. I'll experiment with some different chucks to try and isolate the problem.

[Bruce Pratt]

If you have one, try using a steady rest (even if it is of the two-wheel variety, normally used for spindle work). It may absorb some of the vibrations you are experiencing. The harmonic resonance is a function of speed, wood thickness. location of cut, angle of attack, distance off tool rest, sharpness of the tool, geometry of grind, etc, etc. Try changing some of these variables in a controlled manner. If all else fails, sometimes you just have to live with the noise until you change the wood shape enough to damp out the vibration....

[bob svoboda]

Thanks Bruce. I do have one of Jeff Nicol's steady rests and will give that a 'whirl'.