The ability to remove the neck and scroll of a double bass is wonderful, because it makes the instrument much more easily transportable. 

Read this Talkbass thread for some interesting commentary about who's using it and how.

Here's how my bolt-on neck mechanism works.

It can be done to en existing neck/block with minimal damage, it's about the same amount of work as a neck-reset. If you don't like the result, you can just plug the hole and re-glue the neck into the block.



This is my preferred solution with the smallest practical visible metalwork and minimal change to the existing bass. The hole is plugged with a small brass button.

This is how it looks when finished:



If the neck is well fit into the block, it is as solid as a rock. There is a small amount of adjustment possible by packing the front of the mortise with a shim.

It can be done to en existing neck/block with minimal damage, it's about the same amount of work as a neck-reset. If you don't like the result, you can just plug the hole and re-glue the neck into the block.

Click here to see the modification retro-fit to a New Standard Cleveland bass, together with sound-post port in the C-bout.