Looks good! How did you attach the clip?
Well, I'd read where folks used a burner of some sort to actually scorch a hole through the wood. Since I didn't have a wood burner I used a piece of steel fencing wire, heated it cherry red with a torch and hammered it out to a flat blade shape. Then, heating again to cherry red, applied it to the wood and was amazed how quickly it burned through. Make sure the burned slot is within the bored area of the cap. (Just stick a wire or something down the bore as a depth gauge and then mark the outside to the same depth.) You'll create the slot before "final" shaping so you can turn off any scorching around the slot.
You'll need to modify the clip a bit so it will go into the slot. These components came from a "Comfort" pen. I used a side cutting wire cutter to remove a chunk off the back side of the clip, then put a little squeeze on the remaining bits sticking out so they'd go into the slot. Then slipped a drinking straw down the bore and dropped a few drops of thick CA down the straw. (The straw protects the brass tube from the glue.) Then hold the clip in place til everything hardens. I've read where some use a couple drops of 5 min epoxy for this. That would work too, but I had CA handy so used it.