Eccentric chuck
I recently bought an Axminster Tools eccentric chuck adapter second hand with a view to modifying it to work on my rose engine lathe.
If I mounted this on an chuck and then had a second chuck holding my workpiece I would have had insufficient bed length to be able to ornament the workpiece. As a result I removed the backplate that was intended to be mounted in Axminster C jaws on one of their chucks and I machined up a plate that could be made into a faceplate.
I then machined a 1 1/4 x 8 nut to suit my headstock on the rose engine and mounted the backplate onto it.
To see if this would work successfully I 3D printed a chuck adapter to take a small 80mm Axminster chuck. This will be replaced later with a properly machined steel chuck adapter.
I then tried a small piece of scrap on it and it works fine, below is a short video of it in action.