Exceptional and large pierced scrimshaw whale and walrus ivory crimper America mid -19th century. The top section of the crimper has an elaborate pierced carved design. It is set into and brass pinned to the lower section which has been hollowed out so that it is in two pieces and joins at the bottom section where it supports the wheel. The middle section has an elaborate pierced carved design consistent with the carved design above. One side of the lower section is whale ivory and the opposite side is walrus ivory. The crimper has a carved whale ivory wheel. (SC-1222)
Reference 2: "Scrimshaw and Scrimshanders Whales and Whalemen" by E. Norman Flayderman, New Milford , CT.  1972 page 178.  This example is unusually large and elaborate compared to others of this style. 
Length: 8 7/8 inches