Pen mandrel is vibrating.

[vferdman]

I have read a lot about the mandrel saver, but when I got into pen making I bought a set Woodcraft put together that included an ordinary pen mandrel, not the "saver". I asked the sales guy about it and he said that the "saver" was not necessary and the one in the set is one of the better ones and will not bend. Well, I am 7 pens into it and now I am getting a bit of vibration on the side farthest from the headstock. Not a lot, but annoying and making it difficult to get a smooth surface. Am I doing something wrong or do these types of mandrel all do this? I can not see a bend in it, but as I said, the vibration is slight, so I don't expect to see it with a naked eye. Is there a way to remedy the situation without buying a new rod? The way I use it is tighten up the thumb wheel on the bushings and then bring the tail stock up and tighten the tail stock on the end of the rod lightly, just enough to engage the live center turning. I did not want to put a lot of pressure on the end of the rod because I thought that may bend it. What happened? I may just take the rod or the whole mandrel back to Woodcraft and see if I can get a replacement, but I need to know how to prevent this from happening again. Suggestions welcome.

Also, how do I turn pens between centers without a mandrel? Perhaps that's the better way to go...

 

[sbell111]

My guess is that the tailstock may be slipping slightly so that the end of the mandrel is not seating properly onto your 60° live center. (You are using a 60° live center, right?)

 

[glycerine]

To turn between centers without a mandrel, you'll only be doing one piece of the body at a time. Just put the bushings in the ends of the tube and mount it between your centers. It might help to have the special 60 degree bushings, but I've always just used the stock bushings. I usually turn down ALMOST to the bushings and then remove them and just mount the pen body between centers to finish the sizing. I do this just in case the bushings are slightly out of round. I also made some special bushings out of delrin for doing my CA finishes...

 

[vferdman]

My guess is that the tailstock may be slipping slightly so that the end of the mandrel is not seating properly onto your 60° live center. (You are using a 60° live center, right?)

I am using the live center that came with my Jet 1014. It has a center point that can come out, but I keep it in. Not sure if it's 60 degrees. I do not have any other live centers, so I am stuck with this setup for now. I don't think the tail stock is slipping because I tried tightening it up and still got the vibration.

 

[ed4copies]

You can isolate your problem.

Take everything off the mandrel (no tubes, no bushings, just the rod) and mount it on the lathe as you normally would. Now bring your tool rest up as close as you can.
Slowly move a "sharpie" marker across the tool rest until it just touches the center of the mandrel.

After you have just touched the mandrel, put away the "sharpie" and stop the lathe. You will have a mark on one side of the mandrel. Tap the mark with a hammer and repeat the process.

When you get to a point that the whole mandrel has a circle around it from contacting the "sharpie", your "vibration" is gone.

 

[sbell111]

My guess is that the tailstock may be slipping slightly so that the end of the mandrel is not seating properly onto your 60° live center. (You are using a 60° live center, right?)

I am using the live center that came with my Jet 1014. It has a center point that can come out, but I keep it in. Not sure if it's 60 degrees. I do not have any other live centers, so I am stuck with this setup for now. I don't think the tail stock is slipping because I tried tightening it up and still got the vibration.

I believe that your live center is your problem. The one that came with the lathe is too 'sharp' to seat properly in your mandrel.

Pick up a 60° one and your problem will likely go away.