Pen Blank Drilling Problem

[Daniel Heine]

Hello,

I'm having a problem drilling pen blanks for Jr. Gentleman pens. I bought the bits from Berlands, so they should be decent quality. When I drill the blank, and insert the tube, it's a nice tight fit on the top, but there is a gap around the tube at the bottom on one side. It seems the drill is exiting with an elongated hole. What could cause this? How do I fix it?

Also, how do you glue your tubes in a Polyester Resin blank?

Thanks, the people on this board are the best.

Happy Easter,
Dan Heine

[Joe Melton]

Dan, I don't know what is causing the hole to be lopsided. As for a fix, take a round rasp and file the hole till the tube fits correctly. I use thick CA for gluing in the brass tube.
In the future, if your blanks are long enough, drill deep enough for the tubes, but not through the end of the blanks. Then cut the ends off to expose the hole. Resin tends to blow out more often when the drill exits, and this technique may save you some heartache.
The rasp is useful, too, to clean out dried glue so the blanks will fit onto your mandrel.
Good luck.
Joe

[Pat Salter]

not sure if you are using a "jig" to hold these but I found that I even have to clamp down the jig otherwise the hole doesn't work right. takes a few more secs but......

[Harvey Schneider]

Hi
Drilled holes turn odd shapes when the drill bit is vibrating. This could be caused by runout of the drill chuck or too much pressure on the drill. I've seen triangular holes caused by bad bearings at the quill.

The reason that I am posting is to suggest an alternate method of drilling that I find much more satisfactory for pen blanks.
I first turn the blank to a cylinder between centers. I then cut the cylinder into two appropriate pieces. I chuck each piece in the headstock and mount the drill bit in a Jacobs chuck in the tail stock. I use the tailstock ram to drive the bit gently through the blank. If the ram doesn't have enough travel to do it in one pass, I stop the lathe to reposition the tailstock and retract the ram.
I find that with this process the drill is less likely to wander and there is less likelyhood of blowout at the end of the drilled hole. No jigs or fixtures are needed and you don't even need a drill press. Another advantage is that the work is already a cylinder and on center when it is first mounted to the mandrel. That means less likelyhood of a chunk being ripped off as you begin to turn the pen.
If you find that the hole is coming out oversized it means that your headstock and tailstock are not on center with each other. That is a condition that ought to be corrected anyway.

I hope you find this helpful.
Harvey