Making a Ring Mandrel and Bushings for turning rings on a lathe

I've used a lot of different ring mandrels on metal lathes and am always looking for safer ways for students to turn rings. I've spent money on 'premium expanding ring mandrels' only to have them be too weak (according to the manufacturer after explaining how their premium version of the tool is not strong enough) for the work we do or 'accidental student mistakes' that results in a broken/useless $70 tool. I will never recommend that company or buy a premade one again. Those mandrels are probably better suited for wood lathes and not teenagers/new learners....
I teach students to make their own tooling when needed and eventually I plan on having at least 6 different ring mandrels all made in the shop with custom bushings to fit different sizes and applications for turning rings on a metal lathe. I am not a professional machinist but rather a “a jack of all trades is a master of none, but oftentimes better than a master of one" type of builder. I love to experiment and learn from my mistakes and successes.
If you have a helpful idea leave a coherent constructive comment below. We use the tools and equipment we have available in our shop and do the best with what we are given.
Music:
------------------------------
Up Above by Pyrosion / pyrosion
Creative Commons - Attribution-ShareAlike 3.0 Unported - CC BY-SA 3.0
Free Download / Stream: bit.ly/2PDvEBV
Music promoted by Audio Library • Up Above - Pyrosion (N...
------------------------------
🎵 Track Info:
Title: Up Above by Pyrosion
Genre and Mood: R&B & Soul - Calm
---
🎧 Available on:
Spotify: open.spotify.c....
iTunes: / album .
Deezer: deezer.com/us/...
KZbin: • Pyrosion - Up Above
SoundCloud: / up-above
---
😊 Contact the Artist:
Lessons, mixing, mastering
[e-mail]
[e-mail]
/ pyrosion
kzbin.info....
open.spotify.c....
/ pyrosion
---