Grrr... Right before I'd finished Turning them...

[Esqy]

I hate it when this happens. First time turning Zebrano, and I know why it's called that. Smells like horse poop when drilling it out
No idea what the black wood was, I got it in a box of random pen-turning stuff I bought from Gumtree.

 

[akirk]

Is it possible that your hole for the brass tube is a bit bigger than the brass tube - there are a few kits where the recommended drill size can be reduced by several sizes (in 1:10ths of a millimetre) and a snugger fit is achieved…

In the photo it looks as though the Zebrano may have a gap between it and the tube - when you then get thin it will often go like that…

 

[Esqy]

I was using pretty thin glue on that one, but I found I get better results with Epoxy Resin, but you are right - a snugger fit would probably help a lot more.
All the drill bits I have are either whole numbers or halfs.
These slightly smaller drillbits you mention... Is that an amazon job, or do you reduce them yourself?

 

[Terry - Somerset]

Black could be ebony - I have found it has a tendency to "shatter" even if the tool is sharp and used with a light touch. Having attempted whole pens (with similar results) I now sometimes use it to create a contrasting band.

 

[Esqy]

Yeah, I thought ebony too... I know it was a pig to get through, even with the carbides.
I'm gonna hang onto the non-broken part - Maybe make a contrasting pen or something.

 

[akirk]

The drill bits vary in origin but most have been from pen kit suppliers - it might just be that a drill bit for a different kit gives that better fit, there are also some online suppliers who can provide them, eg Tracy Tools https://www.tracytools.com/product-category/drills-hss/drills-cobalt-metric-drills-hss/
It would set you back £100s to buy them all but to get the odd one they do up to 11mm in 0.1 increments…
I have found it makes a huge difference

 

[Paul Hannaby]

The dark blanks are probably african blackwood. It's somewhat harder than ebony.