The Pearling Tool is a hand-operated fly cutter which uses an ID rosette, which is inside the knurled ring in front of the indexing ring. It is a variation of the rose cutting frame.
Additional pictures of this device
Disclaimer: eMail comments to me at OTBookOfKnowledge @ Gmail.com. The process of woodturning involves the use of tools, machinery and materials which could cause injury or be a health hazard unless proper precautions are taken, including the wearing of appropriate protective equipment.