Small box

I've never done inlay like this, so knowledgeable suggestions from experience are non-existant. I would think though, that copper could be tapered with sandpaper. Just thinking here, but bend the end of the wire over a piece of wood, either at a 90 deg. or 45 deg. angle and taper the end with sandpaper or file.

When Holly is inlaid it is 1/16' wide often in "String and Berry"   or "String and Beads".   Often the ends of a line has a round "bead" or "berry".    thus the ends are capped.    Could do that with the copper.   

Think Oldtool has the answer for the tapered ends for going that route.    

Looks pretty nice, the piece posted.  

Nicely done. Having no experience, I’d have to say sanding sounds reasonable to me too. One off, custom fit!

Thanks for the comments and suggestions. I did try the sand paper technique. It was hard, for me, to hold the round wire in the proper orientation for its inlay position.  More practice!

Maybe a pin vise would help with that? 

Not sure if it would be easier with a hand vise and sanding, or a small jewellers anvil and just hammering the taper in.
Splint did twisted copper wire inlays, but I don't know if he tapered anything to fit.

Looks good though.

Never had to deal with the ends fitting nicely 🤠

I can see why the string/berry technique is common, just avoid the tapered fitting by adding a joint element that hides the detailed misery!

Are you hammering flat the wire, or just laying it in a groove and then sanding the surface flat? 
Either way, you can also get decent tapers from simple diagonal wire cutters which "pinch" the wire apart leaving a tapered point versus shears (flat point).

Copper is also very malleable so if the wire comes up a tad short, it is easy to stretch (unlike wood 😩)

For shaping the tip on a sanding block, the only thing I can think of would be to use a scrap of wood with a groove cut for the wire to hold it securely. Press in the wire so the end  is even with the wood scrap, then drag the wood over the sanding block to taper. If you know the required angles, you could cut those angles into the wood as a guide.

not bad, ive always wanted to try string inlay. keep at it, practice makes perfect.

Again, thanks for great suggestions. I’ll give them all a try.