HELP!! Never had this happen before...

[Warren White]

As you can see by the photo (I hope it shows properly), I am really puzzled. I recently purchased 3 blanks from Craft Supplies. This issue is not their problem obviously. I buy from them A LOT, and am always happy.

I prepared three blanks for turning (cut in half; drilled using my lathe, inserted the brass tubes). After the glue set up, I noticed some of the tubes

weren't centered on the hole. It turns out none of the tubes were perfectly centered on the hole, some worse than others.

My first thought was that I had chosen something other than a 7 mm drill. I keep my 7 mm bits in a bag appropriately labeled, so I checked all of the bits with a gauge and they are all right on.

Your thoughts as to what I have done wrong?

 

[sorcerertd]

The only thing that comes to mind is that maybe the bit had some wobble as it went through the blank. I've had that happen and noticed that the hole was flared (for lack of a better word) on the ends, but OK in the middle. It's not always OK in the middle as I have had to use a round file to get the tube to slide in without having to force it, but the point is that it's a larger diameter on the end(s) when that happens to me.

On the bright side, it's not going to crack when you press something into that end.

 

[leehljp]

That can happen on rare occasion. Back around 2007 or 2008 there was a production run of off center bushings (of a specific pen model). I had one and still have it somewhere that was visually off center as is the tube in the photo above.

 

[1080Wayne]

Bits can be bent . It doesn`t take much to distort the hole . Check by rolling on a dead flat surface . They can also become scarred in a chuck , and not seat properly when used the next time .

 

[jttheclockman]

As you can see by the photo (I hope it shows properly), I am really puzzled. I recently purchased 3 blanks from Craft Supplies. This issue is not their problem obviously. I buy from them A LOT, and am always happy.

I prepared three blanks for turning (cut in half; drilled using my lathe, inserted the brass tubes). After the glue set up, I noticed some of the tubesView attachment 378277 weren't centered on the hole. It turns out none of the tubes were perfectly centered on the hole, some worse than others.

My first thought was that I had chosen something other than a 7 mm drill. I keep my 7 mm bits in a bag appropriately labeled, so I checked all of the bits with a gauge and they are all right on.

Your thoughts as to what I have done wrong?

As mentioned check that bit is straight. Next could it be that you did not chuck the blank up securely? Are the blanks square? What chuck did you use. ??

 

[mnerland]

Did it affect the pen fit and finish after turning? Just wondering....I have seen this on my ends of blanks also, but the pen turned out OK.

 

[Warren White]

Thanks all of you for reading and giving me suggestions. I believe that I think that jttheclockman had it right. I am using a Vicmark VM120 chuck. When I rechucked the blank, I noticed that the blank (which was not exactly square) wasn't touching on both sides of the two arms of the chuck. I moved the blank one turn and rechucked it with all four sides being supported. The resulting hole was perfect. Contributing to my error was an observation I made some time ago, when I found that I was tightening the chuck too much and it was causing the drill bit to get bound up a bit. So, I haven't really checked the blnk/chuck connection, and opting not to tighten it too much.

To mnerland: I didn't do anything further than put the tubes in. It was clear at that point that the error seen on the blank would carry through when I put either the tip or cap on the blank.

Again, thanks to all!

 

[rherrell]

You haven't done anything wrong and why does it matter? Whether you use a mandrel or TBC bushings the tube will automatically be centered after turning.

 

[Mortalis]

You haven't done anything wrong and why does it matter? Whether you use a mandrel or TBC bushings the tube will automatically be centered after turning.

I have also had this happen to me on occasion and I would just fill the gap with thin CA glue to be sure the blank doesnt collapse upon turning. The gap will be covered by the hardware after installation.
Rick has it right. The ID of the tube is your centering for the turn regardless of how 'off center' it may be. The only issue you might encounter is if the resulting gap is larger than the finished wall thickness.

 

[JohnU]

The only issue I see is there is very little material left on a 7mm pen so you might expose the void along the tube when turned down to bushings. Something else to mention is heat when drilling. Make sure you clear the hole of drilling debris often when drilling acrylics. The debris rolling around the drill bit can actually stretch the hole larger if the blank gets warm from drilling, resulting in a larger hole than needed.

 

[jttheclockman]

It absolutely matters if you are using a segmented blank or a blank with some sort of pattern in it. So best to correct before this happens. As mentioned the size of the wandering hole can matter with the kit being used. You can actually turn into that void down by the ends. That can result into needing oops bands or some other fix.

 

[Warren White]

Again, thanks to all for your suggestions. I went over to my good friend dieseldoc and he suggested that my problem was quite possibly chuck related (my thought is that the chuck related issue was greatly magnified by my sloppy use of the chuck). I have cleaned the chuck, modified my use of the chuck, and it seems my problem went away.

Nice thing about this hobby, is that you can learn with each experience, and the friends you make are GREATLY appreciated. I suppose as has been suggested I could use the blanks that I messed up, but I fear the blanks could possibly crack when I turn them down to the bushings and I really don't want to have that happen after all the work it would take to be ready to assemble them.

Again, thanks to all! A GREAT group!