Ah we use those exact parts for our ring-lights at work. We order everything from McMaster-Carr. www.mcmaster.com

On the main page go to "Fastening and Sealing" and then "Spacers and Standoffs". Follow the selection guide until you end up with the part you want. I think you can order online even if you don't have an account with them.

Wow I think we get a lot better price than the web page lists though!

If you can wait I can bring a few to the S.F. meet. The ones we use are M3 x 10 aluminum I think. We also have M3 x 6 stainless with a bigger OD. Can you measure yours? The body length is only the hex part, not the threaded part.

Speedy