mandrel
Mandrel (noun) means a rod or bar used to shape or support a material while it is being formed, such as when bending a pipe or shaping a ring.
Etymology
Taken from French mandrin, probably from Vulgar Latin *mamphurinum, itself from Latin mamphur (“a bow drill”), which goes back ultimately to Oscan or Ancient Greek μαννοφόρον (mannophóron, “wearing a collar”), formed from μανά (maná, “collar”) and φέρω (phérō, “to bear”); the first element is cognate with Latin monile (“collar”).