Why is this happening?

[RonSchmitt]

I am turning between centers, and not sure what to check next. I cleaned out the morse taper, tightened everything down, and still am getting oval pens. Any ideas???

 

[Monty]

Do the points of your dead and live center line up correctly?

 

[vallealbert]

Does it occur when turning non cross cut pen blank?... I noticed you turn a cross-cut blank and almost all cross-cut pens I turn are slightly oval shape...it seems some areas of the cross cut blanks are harder and others softer, and during sanding the pressure you do over the blank cause the oval shape pen...

 

[ed4copies]

Try different bushings--some are not drilled in the center.

 

[Ruby pen turning]

Maybe get rid of the bushings and insert the centers directly into the tube careful to not over tighten. Then use the bushings or a calipers to get the correct end size.

 

[IPD_Mr]

First make sure that when you mill the ends of your blanks that it is square. If you are off by a couple of degrees you can be out of round when turning. Next check and make sure the tapers for your dead and live centers is clean, both male and female side. Then take a good look at the center points and make sure they are clean and smooth. Last would be the bushings. Make sure they are clean. Also it looks like you are using standard bushings. The outer hole is not cut at 60 degrees if it is. I highly recommend JohnyCNCs bushings with TBC method.

 

[ossaguy]

Does it occur when turning non cross cut pen blank?... I noticed you turn a cross-cut blank and almost all cross-cut pens I turn are slightly oval shape...it seems some areas of the cross cut blanks are harder and others softer, and during sanding the pressure you do over the blank cause the oval shape pen...

That's what I've experienced too,so although it seems to take forever to do,when I get it down close to the bushings,I'll stop and even it out sanding length-wise so it ends up not oval shaped.


Steve

 

[okiebugg]

OVAL

First make sure that when you mill the ends of your blanks that it is square. If you are off by a couple of degrees you can be out of round when turning. Next check and make sure the tapers for your dead and live centers is clean, both male and female side. Then take a good look at the center points and make sure they are clean and smooth. Last would be the bushings. Make sure they are clean. Also it looks like you are using standard bushings. The outer hole is not cut at 60 degrees if it is. I highly recommend JohnyCNCs bushings with TBC method.

What they said

Make sure that you're not putting too much pressure on your blanks with your mandrel nut. Sometimes you start out with a square blank that is difficult to get started because of the square corners hitting your tool and stopping the rotation of the blank...The answer is to tighten the nut so you can make it round. Make sure that if you have to tighten that nut, that you loosen it as soon as your blank will turn with less pressure on your tool.

 

[fernhills]

+ 1 on the above..

 

[Johnny westbrook]

Check to make sure that your head stock shaft is not running out, that was my problem i had to make a new head shaft to get it right.
my shaft was out .009

 

[Daniel]

I had a lathe that was horrible for this. Notice I said had. Replacing the lathe ended up being my fix. Until I was able to do that I would turn the pen about as far down as you have in the photo. Then turn the blank on the mandrel about 90 degrees and turn again. and sometimes turn it another 90 degrees. Not a perfect fix but it came very close. I never was able to get a larger item like a pepper mill to be centered. I finally after several years just replaced the lathe though.