Here is a jump ring forming and sawing tip from @marquisjewelryacademy - “You can use wooden dowels from craft/hardware stores, hand made shapes, or found, like I've taped together 4 coffee stirrers to get my ideal shape.
I formed my links around the wooden mandrel, then sawed them open while still having the wood support.
When crafting a wood jump ring mandrel you can reuse by sawing in just a half inch, when you've sawn off those links, push the coil to the end, and saw again.
This method is great for soft/thinner links, like this 1mm square wire paperclip chain.” Love this so much Emily! Thank you for letting me share! I love chain making tips, please send me yours at tips@metalsmithsociety.com