I have a Jet 1442 that is about 4-5 years old with modest use. Yesterday, I was finish-turning a shallow maple bowl about 11 inches in diameter. It was dry, and securely attached with a 4 supernova jaws expanded into a recess. Everything was locked down tightly and the rest was close to the workpiece. While making a final passes on the interior I was getting sympathetic vibration when making a scraping cut. Even with light (axial) pressure, both at the axis and 3 inches out I would get a vibration that would go away as soon I removed all pressure from the cut. There also seems to be a low-pitched hum when the motor is running  that I'm not sure has always been there. So, I'm wondering if my bearings are going.  My questions are this: 1. Do (can)  bearings fail with axial rather than radial slop? 2. How do I know that a bearing is bad/going? 3. Has anyone over done a bearing replacement on a Jet1442... and how big of a deal was it? Thanks, Steve ** Posted from http://www.teranews.com **

Well Robo, I used to work with a guy that used to say in a thoughtful tone of voice, I guess that about sums it up . Great post of good advice. Robert

I have a Jet 1442 that is about 4-5 years old with modest use. Yesterday, I was finish-turning a shallow maple bowl about 11 inches in diameter. It was dry, and securely attached with a 4 supernova jaws expanded into a recess. Everything was locked down tightly and the rest was close to the workpiece. While making a final passes on the interior I was getting sympathetic vibration when making a scraping cut. Even with light (axial) pressure, both at the axis and 3 inches out I would get a vibration that would go away as soon I removed all pressure from the cut. robo hippy pretty much gave you the answer, but let me add a note it is almost for sure NOT your bearings - think of the bowl as a bell - when you stimulate it, it rings - you aren't smacking it with a clapper, but you are stimulating it with the cutting tool.  this gets increasingly pronounced as the walls get thinner.  That is why, when turning thin, you turn a little bit at a time starting from the outer edge - maybe 1/2 to 1 inch at a time max, turn to near final thickness leaving the mass in the center to keep the bowl from resonating. A scraper presents a much larger surface to the resonator than a gouge, so it puts more vibrational energy into it.  Angling the scraper as Robo said reduces the cross sectional area that is excited and also makes it more of a shear cutter and both help. I have had good luck putting a large rubber band around the outside to deaden the vibration, but this works only when you are pretty thin (say well below 1/4, pushing 1/8 inch) - varying speed also helps.  But the main thing is to be sure you are cutting not scraping. ** Posted from http://www.teranews.com **