turning is off centre

[stuarty1]

Why is it that when I turn two blanks and get them finished to a good standard that when I build the pen that the two sections don't run true. When I fit the nib one side of the wood has an excess and the other is lacking. It seems that something isn't running true and I can't work it out . Everything seems to be running true and smooth.

 

[ed4copies]

Put your bushings on the mandrel and turn on the lathe--tailstock and 60 degree center should be up against the mandrel, as if you were turning a pen. NO brass tube or pen parts on the lathe, just the bushings.

Does the mandrel turn true or "wobble"? Do each of the bushings turn true or "wobble"?

This will, most likely identify the part that is causing you to turn ovals.

 

[MarkD]

If the lathe is aligned properly my next suspicion is that you are probably using a mandrel and bushings. The bushings that come from the pen kit suppliers are often not very accurate. You will find that alot of people do what called "turning between centers" rather than using a mandrel and bushings. Another opinon is to use bushings designed to be used between centers ( See penturnersproducts.com ). I believe there are several articles in the library regarding turning between centers ( or TBC for short ).