Cap and body diameter off

[HugeElvis]

That vague title is what I have recently found in two pens. After I finish shaping the pens, the bottom rim of the cap and the top rim of the body don't match exactly. One is slightly out of round I think. This is only on pens that have the same diameter, cap isn't proud. It is so slight I can hide it with sanding to blend but it makes me crazy. The only thing that is different is I bought a bearing collet nut, the piece you screw onto the collet chuck. Any ideas. It's not every pen, but any is too many
Thanks

 

[Curly]

Long shot but how are you putting the collet, assumed to be an ER series, into the nut? If you just place it in the nut and screw together you are doing it wrong and that could be why the misalignment. It should be tipped under the ring/lip in the nut into the groove of the collet and then screwed together. If you are tipping it in,,,,,,,,then never mind.

Pete

 

[HugeElvis]

Thanks Curly. I do snap the collet into the chuck first, but you made me think there may be an issue with the new bearing collet chuck being slightly off from old collet chuck

 

[d_bondi]

Jim,

I use bearing collet nuts and haven't had this problem ().

Can you provide a bit more information on your process so we can help?

For example...

1. Are these kitless pens or perhaps Apollo or Artemis kits from Bulllseye?
2. Are you turning these on mandrel?
   1. If so, do you check the mandrel for concentricity before you start?

Any information you can provide will help.

David

 

[HugeElvis]

1. these are kitless pens mostly from 8.5x3/4 blanks I pour. The blanks are mostly true, but not all
2. Are you turning these on mandrel - I use a mandrel. I have checked it with a gauge, but before I screw the pen part onto the mandrel I run it at slow speeds to look for wobble.
3. Since it's not in every pen, I'm wondering if my cap threads could be the problem. Maybe not, because after I have cap and body threaded, I'll screw the two together to see if they are true and they are
4. 14mmx0.8 mm triple start
5. If I shape the cap to be proud, I don't notice the out of roundness, very slight and if I see it on the "completed" pen, I can screw the pen together, place in collet and wer sand it down to flush to mask the out of roundness

 

[HugeElvis]

More info. First photo is end of cap for clip. It's off center. The following photos are tail stock head stock alignment.

I found out the reason, but not the cause