Third Funline Pen…almost

Chip-out due to excessive pressure on untrimmed blank.

Today’s third attempt to turn a funline pen was a fail. I’ll put my notes in here as a learning experience.

I experienced the same chatter on the tailstock side even with sharp tools today. I tightened up the tailstock with the hope of redusinging it only to hear a crack,which at the time I thought might just be normal. Later, during sanding, i discovered a tiny chip out of what would have been the center band end of the upper tube. I also realised when i took the tubes off the lathe that i didn’t true up two of the ends with a barrel trimmer.

Pen blank ends not milled
Forgot to mill ends, the acrylic is longer than the tube.
Forgot to mill ends
Forgot to mill ends, not as bad on this end but still not flush.

That would explain why tightening the tailstock cracked the tube. Putting pressure directly on the resin instead of the brass tube is never a good idea. I’m hoping that’s why i was getting that chatter too.

I’m having trouble getting the blanks drilled right. This blank and the next have a slight gap around the tube on one end as if the hole is more oval than round. Not sure how to remedy that with the drill press. Might have to try a pen chuck/drill chuck system for the lathe.

Better luck next time.

Update on chatter during pen turning (2017/12/03)

I figured out why I’m getting chatter. The pen I finished today is slightly out of round. I experienced the same chatter while working on the tailstock side of this pen. Turns out that the bushing is sitting on the threaded end of the mandrel rod, not on the rod itself. So it’s not necessarily staying centered on the shaft. This allows for both vibration and an eccentricity while turning. Unfortunately, the Apprentice Pen Mandrel I have is not long enough to have both tubes of the funline pen kit installed and have all three bushings rest on the shaft. I’ll have to pick up an adjustable mandrel or just install one blank at a time.

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