I have made this spindle handle for my mini lathe (a bit old project, but its worth mention it).
The design is not mine; I've copied it from toolsandmods. You can find it on toolsandmods library and projects, original design Ralph Patterson.
In the original design the barrel assembly has three parts, the barrel itself, a sleeve (milled square at one end, for attaching it to the arm) and a nut for securing the barrel with the sleeve in the arm. Since I hadnít a milling machine (I still donít have one) to make the sleeve from one piece of steel, I used two pipe fittings, a steel threaded connector and a brass pipe cap.
I did a couple minor changes for securing the parts and some for the appearance of the tool; you will see these on the video.
I use this tool almost in every project that I have for the lathe; however in order to have a more versatile tool, I made a bigger arm and changed the tightening bolt with a threaded shaft that has a knob.
All the best