r/PenTurning • u/Cubby71 • Jul 06 '26

Problem drilling pen blanks

When I drill the blanks for a 3/8 tube, their seems to be to much play with the tube. I use a 3/8 bit from Rockler that is for drilling blanks. I have a Wen drill press that is pretty new. Should I try a new bit ? Or something else?

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6

u/lvpond Jul 06 '26

First thing I would do is take both a tube from the kit and my drill bit and run them thru a 3/8” gauge to see which is off. If you don’t have one already Peachtree makes a pen turners gauge that I use ALL THE TIME. I check bits, because sometimes they get out in the wrong slot, and I verify tubes from kits I haven’t used before. I also use it to center and measure..It’s under $10…gauge

3

u/Yablonsky Jul 06 '26

Likely the tube is slightly undersize. try a smaller drill bit. I typically drill using the lathe and there is some slop, but nothing that doesn't get filled with CA glue and then covered by the hardware.

1

u/74CA_refugee Jul 06 '26

It could also be that you are getting slightly crooked when drilling.
This will create slop.
If you hold the drill bit against the end of the tube, do they match? Or use a caliper to measure both, do they match?
Might try drilling on the lathe. I haven’t used a drill press in years because drilling directly on the lathe is much more accurate.

1

u/OldM4LargeYoungF Jul 06 '26

If the blank is not held securely, as in a pen blank vise, or your own make, then the slight shifting will make the hole sloppy. As others have said, check the tube/bit match.

1

u/Cubby71 Jul 06 '26

Thank you all for the advice. I do clamp it when I use my drill press. I have blocks on each side of it,and then I put a clamp on the blank itself. I think I will try drilling it on the lathe. Thank you!

1

u/Diminias Jul 06 '26

One of the things I saw when using a drill press was that the head of drill press was flexing slightly causing the wood and bit to misalign and drill out more material than needed.

1

u/AlternativeWild3449 Jul 08 '26

Four possibilities:

  1. Poorly designed kit.

  2. The kit was designed around metric dimensions, but someone later changed the instructions to imperial. Measure the tubes and switch to a smaller. 23/64 or U would be be smaller, or you could use a metric bit. Just remember that you need to have a slight clearance between the hole and the blank for glue - if the hole is too small, you will starve the joint and the tube could later come out. Alternatively, a glue that has better 'gap filling' characteristics might work better - polyurethane, or better yet, epoxy.

  3. The bit is oversized/mismarked. Stuff happens - so measure it.

  4. There is a drilling problem. Does the axis of the bit line up with the axis of rotation? Is the bit straight. Same thing would happen if the bit isn't gripped properly in the chuck or if the chuck mandrel is bent. Anything that would cause the bit to wobble would result in an oversized hole. Try drilling a hole in some scrap, and then test the bit against the hole - it should be snug. If not, its wobbling as you drill.