Pen Problem

[Jason Christenson]

This weekend I turned my first pen. The finish looks good (If I do say so myself!) but the pen is slightly out of round. Consequently, on one side the wood is nice and flush with the tip, band, etc, but on the other side it is not. I intend to make a LOT more of these so I am hoping someone may have an idea where I went wrong. Thanks.

[David Fried]

I experienced that when I bent my mandrel. You might check that. Good Luck!

[Raymond Overman]

Tightening the tailstock down too much can cause the mandrell to bow which in turn causes the pen to be out of round. I think there is a good primer in the files section of the Yahoo penturners group discussing aligning the headstock and tailstock of the lathe, mounting the pen blank, and insuring it's square on the lathe. If I have a chance, I'll see if I can find it.

Otherwise, It's a design feature, not a pen problem. :)

[Thomas Wyatt]

Tailstock and bent mandrel are two reasons I have been told.

I now check the mandrel with every pen to restraighten it. The tailstock is snug but I can still rotate the center by hand.

[Keith Nielsen]

While you have the pen in turning on the mandrel, finish making your ruffing cuts. At this point your pen body should be completely round. Now take one or two light cuts with the skew. If you notice that as you get to the end of a wood part toward the bushing you start to get vibration or chatter in the wood, back off the tail stock a little bit. Now take another light cut if you can do it without chatter then you should be set up for the rest of the finishing cuts. This will take the bow slowly out of the mandrel and turn the pen true round. I have also found that if you do not have a nice point on your tail stock taper it will encourage the mandrel to wander. Hope this helps

Good luck
Keith

[Harry Pye]

Tailstock too tight is one way to create a bow in the mandrel. Another is to tighten the brass nut that squeezes the two blanks between the bushings. This should be just tight enough to keep the blanks from slipping.

Just before you make that last smoothing cut, turn off the lathe and check the tightness of this nut. They seem to tighten up during the turning.

[Robert E Lee]

With some woods if you do a lot of sanding to bring them to size might make it out of round. It will eat the solf wood faster on two sides.
Bob